Changes from the previous draft (N1256) are indicated by ''diff marks'' in the right
margin: deleted text is marked with ''*'', new or changed text with '' ''.
-
-
-
[page i]
-
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<a name="Contents" href="#Contents">Contents</a>
<a href="#6.4.8"> 6.4.8 Preprocessing numbers . . . . . . . . . . . . . . . . 74</a>
<a href="#6.4.9"> 6.4.9 Comments . . . . . . . . . . . . . . . . . . . . . 75</a>
-
[page iii]
<a href="#6.5"> 6.5 Expressions . . . . . . . . . . . . . . . . . . . . . . . . 76</a>
<a href="#6.10.2"> 6.10.2 Source file inclusion . . . . . . . . . . . . . . . . . 163</a>
<a href="#6.10.3"> 6.10.3 Macro replacement . . . . . . . . . . . . . . . . . . 165</a>
-
[page iv]
<a href="#6.10.4"> 6.10.4 Line control . . . . . . . . . . . . . . . . . . . . . 172</a>
<a href="#7.19"> 7.19 Common definitions <stddef.h> . . . . . . . . . . . . . . . 287</a>
<a href="#7.20"> 7.20 Integer types <stdint.h> . . . . . . . . . . . . . . . . . . 289</a>
-
[page vi]
<a href="#7.20.1"> 7.20.1 Integer types . . . . . . . . . . . . . . . . . . . . 289</a>
<a href="#7.26.2"> 7.26.2 Time manipulation functions . . . . . . . . . . . . . . 386</a>
<a href="#7.26.3"> 7.26.3 Time conversion functions . . . . . . . . . . . . . . . 388</a>
-
[page vii]
<a href="#7.27"> 7.27 Unicode utilities <uchar.h> . . . . . . . . . . . . . . . . . 395</a>
<a href="#7.30.10"> 7.30.10 General utilities <stdlib.h> . . . . . . . . . . . . . 453</a>
<a href="#7.30.11"> 7.30.11 String handling <string.h> . . . . . . . . . . . . . 453</a>
-
-
[page viii]
<a href="#7.30.12"> 7.30.12 Extended multibyte and wide character utilities
<a href="#H.2"> H.2 Types . . . . . . . . . . . . . . . . . . . . . . . . . . . 542</a>
<a href="#H.3"> H.3 Notification . . . . . . . . . . . . . . . . . . . . . . . . 546</a>
-
[page x]
<a href="#I">Annex I (informative) Common warnings . . . . . . . . . . . . . . . . 548</a>
<a href="#K.3.9.1"> K.3.9.1 Formatted wide character input/output functions . . . 624</a>
<a href="#K.3.9.2"> K.3.9.2 General wide string utilities . . . . . . . . . . . 635</a>
-
-
[page xi]
<a href="#K.3.9.3"> K.3.9.3 Extended multibyte/wide character conversion
<a href="#Bibliography">Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . 650</a>
<a href="#Index">Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653</a>
-
-
-
-[<a name="#pxii" href="pxii">page xii</a>] (<a href="#Contents">Contents</a>)
+[<a name="pxii" href="#pxii">page xii</a>] (<a href="#Contents">Contents</a>)
<a name="Foreword" href="#Foreword"><b> Foreword</b></a>
1 ISO (the International Organization for Standardization) and IEC (the International
ISO/IEC TR 19769:2004)
-- type-generic expressions
-
-[<a name="#pxiii" href="pxiii">page xiii</a>] (<a href="#Contents">Contents</a>)
+[<a name="pxiii" href="#pxiii">page xiii</a>] (<a href="#Contents">Contents</a>)
-- static assertions
-- anonymous structures and unions
-- hexadecimal floating-point constants and %a and %A printf/scanf conversion
specifiers
-
-
-[<a name="#pxiv" href="pxiv">page xiv</a>] (<a href="#Contents">Contents</a>)
+[<a name="pxiv" href="#pxiv">page xiv</a>] (<a href="#Contents">Contents</a>)
-- compound literals
-- designated initializers
-- additional strftime conversion specifiers
-- LIA compatibility annex
-
-[<a name="#pxv" href="pxv">page xv</a>] (<a href="#Contents">Contents</a>)
+[<a name="pxv" href="#pxv">page xv</a>] (<a href="#Contents">Contents</a>)
-- deprecate ungetc at the beginning of a binary file
-- remove deprecation of aliased array parameters
the ISO/IEC Directives, this foreword, the introduction, notes, footnotes, and examples
are also for information only.
-
-
-
-[<a name="#pxvi" href="pxvi">page xvi</a>] (<a href="#Contents">Contents</a>)
+[<a name="pxvi" href="#pxvi">page xvi</a>] (<a href="#Contents">Contents</a>)
<a name="Introduction" href="#Introduction"><b> Introduction</b></a>
1 With the introduction of new devices and extended character sets, new features may be
5 The language clause (clause 6) is derived from ''The C Reference Manual''.
6 The library clause (clause 7) is based on the 1984 /usr/group Standard.
+[<a name="pxvii" href="#pxvii">page xvii</a>] (<a href="#Contents">Contents</a>)
-
-[<a name="#pxvii" href="pxvii">page xvii</a>] (<a href="#Contents">Contents</a>)
-
-
-
-[<a name="#pxviii" href="pxviii">page xviii</a>] (<a href="#Contents">Contents</a>)
+[<a name="pxviii" href="#pxviii">page xviii</a>] (<a href="#Contents">Contents</a>)
<a name="1" href="#1"><b> 1. Scope</b></a>
1 This International Standard specifies the form and establishes the interpretation of
- programs written in the C programming language.1) It specifies
+ programs written in the C programming language.<sup><a href="#note1"><b>1)</b></a></sup> It specifies
-- the representation of C programs;
-- the syntax and constraints of the C language;
-- the semantic rules for interpreting C programs;
conforming implementation.
- 1) This International Standard is designed to promote the portability of C programs among a variety of
+ <sup><a name="note1" href="#note1"><b>1)</b></a></sup> This International Standard is designed to promote the portability of C programs among a variety of
data-processing systems. It is intended for use by implementors and programmers.
-[<a name="
#p1" href="p1">page 1</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p1" href="#p1">page 1</a>] (<a href="#Contents">Contents</a>)
<a name="2" href="#2"><b> 2. Normative references</b></a>
8 IEC 60559:1989, Binary floating-point arithmetic for microprocessor systems (previously
designated IEC 559:1989).
-
-
-
-[<a name="#p2" href="p2">page 2</a>] (<a href="#Contents">Contents</a>)
+[<a name="p2" href="#p2">page 2</a>] (<a href="#Contents">Contents</a>)
<a name="3" href="#3"><b> 3. Terms, definitions, and symbols</b></a>
behavior that depends on local conventions of nationality, culture, and language that each
implementation documents
-
-[<a name="#p3" href="p3">page 3</a>] (<a href="#Contents">Contents</a>)
+[<a name="p3" href="#p3">page 3</a>] (<a href="#Contents">Contents</a>)
2 EXAMPLE An example of locale-specific behavior is whether the islower function returns true for
characters other than the 26 lowercase Latin letters.
1 character
single-byte character
<C> bit representation that fits in a byte
-[<a name="#p4" href="p4">page 4</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p4" href="#p4">page 4</a>] (<a href="#Contents">Contents</a>)
<a name="3.7.2" href="#3.7.2"><b> 3.7.2</b></a>
1 multibyte character
either an object of scalar type, or a maximal sequence of adjacent bit-fields all having
nonzero width
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+[<a name="
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2 NOTE 1 Two threads of execution can update and access separate memory locations without interfering
with each other.
3 NOTE 2 Implementations that support the extensions in <a href="#K">annex K</a> are required to verify that the runtime-
constraints for a library function are not violated by the program; see <a href="#K.3.1.4">K.3.1.4</a>.
-[<a name="
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+[<a name="
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<a name="3.19" href="#3.19"><b> 3.19</b></a>
1 value
1 perform a trap
interrupt execution of the program such that no further operations are performed
2 NOTE In this International Standard, when the word ''trap'' is not immediately followed by
- ''representation'', this is the intended usage.2)
+ ''representation'', this is the intended usage.<sup><a href="#note2"><b>2)</b></a></sup>
<a name="3.20" href="#3.20"><b> 3.20</b></a>
1 [^ x^]
-
2) For example, ''Trapping or stopping (if supported) is disabled...'' (<a href="#F.8.2">F.8.2</a>). Note that fetching a trap
+
<sup><a name="note2" href="#note2"><b>2)</b></a></sup> For example, ''Trapping or stopping (if supported) is disabled...'' (<a href="#F.8.2">F.8.2</a>). Note that fetching a trap
representation might perform a trap but is not required to (see <a href="#6.2.6.1">6.2.6.1</a>).
-[<a name="
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+[<a name="
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<a name="4" href="#4"><b> 4. Conformance</b></a>
containing a #error preprocessing directive unless it is part of a group skipped by
conditional inclusion.
5 A strictly conforming program shall use only those features of the language and library
- specified in this International Standard.3) It shall not produce output dependent on any
+ specified in this International Standard.<sup><a href="#note3"><b>3)</b></a></sup> It shall not produce output dependent on any
unspecified, undefined, or implementation-defined behavior, and shall not exceed any
minimum implementation limit.
6 The two forms of conforming implementation are hosted and freestanding. A conforming
<a href="#7.9"><iso646.h></a>, <a href="#7.10"><limits.h></a>, <a href="#7.15"><stdalign.h></a>, <a href="#7.16"><stdarg.h></a>, <a href="#7.18"><stdbool.h></a>,
<a href="#7.19"><stddef.h></a>, and <a href="#7.20"><stdint.h></a>. A conforming implementation may have extensions
(including additional library functions), provided they do not alter the behavior of any
- strictly conforming program.4)
+ strictly conforming program.<sup><a href="#note4"><b>4)</b></a></sup>
-
3) A strictly conforming program can use conditional features (see <a href="#6.10.8.3">6.10.8.3</a>) provided the use is guarded
+
<sup><a name="note3" href="#note3"><b>3)</b></a></sup> A strictly conforming program can use conditional features (see <a href="#6.10.8.3">6.10.8.3</a>) provided the use is guarded
by an appropriate conditional inclusion preprocessing directive using the related macro. For example:
#ifdef __STDC_IEC_559__ /* FE_UPWARD defined */
/* ... */
/* ... */
#endif
- 4) This implies that a conforming implementation reserves no identifiers other than those explicitly
+ <sup><a name="note4" href="#note4"><b>4)</b></a></sup> This implies that a conforming implementation reserves no identifiers other than those explicitly
reserved in this International Standard.
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+[<a name="
p8" href="#p8">page 8</a>] (<a href="#Contents">Contents</a>)
-7 A conforming program is one that is acceptable to a conforming implementation.5)
+7 A conforming program is one that is acceptable to a conforming implementation.<sup><a href="#note5"><b>5)</b></a></sup>
8 An implementation shall be accompanied by a document that defines all implementation-
defined and locale-specific characteristics and all extensions.
Forward references: conditional inclusion (<a href="#6.10.1">6.10.1</a>), error directive (<a href="#6.10.5">6.10.5</a>),
- 5) Strictly conforming programs are intended to be maximally portable among conforming
+ <sup><a name="note5" href="#note5"><b>5)</b></a></sup> Strictly conforming programs are intended to be maximally portable among conforming
implementations. Conforming programs may depend upon nonportable features of a conforming
implementation.
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+[<a name="
p9" href="#p9">page 9</a>] (<a href="#Contents">Contents</a>)
<a name="5" href="#5"><b> 5. Environment</b></a>
preprocessing directives (<a href="#6.10">6.10</a>).
<a name="5.1.1.2" href="#5.1.1.2"><b> 5.1.1.2 Translation phases</b></a>
1 The precedence among the syntax rules of translation is specified by the following
- phases.6)
+ phases.<sup><a href="#note6"><b>6)</b></a></sup>
1. Physical source file multibyte characters are mapped, in an implementation-
defined manner, to the source character set (introducing new-line characters for
end-of-line indicators) if necessary. Trigraph sequences are replaced by
- 6) Implementations shall behave as if these separate phases occur, even though many are typically folded
+ <sup><a name="note6" href="#note6"><b>6)</b></a></sup> Implementations shall behave as if these separate phases occur, even though many are typically folded
together in practice. Source files, translation units, and translated translation units need not
necessarily be stored as files, nor need there be any one-to-one correspondence between these entities
and any external representation. The description is conceptual only, and does not specify any
particular implementation.
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+[<a name="
p10" href="#p10">page 10</a>] (<a href="#Contents">Contents</a>)
2. Each instance of a backslash character (\) immediately followed by a new-line
character is deleted, splicing physical source lines to form logical source lines.
of such a splice. A source file that is not empty shall end in a new-line character,
which shall not be immediately preceded by a backslash character before any such
splicing takes place.
- 3. The source file is decomposed into preprocessing tokens7) and sequences of
+ 3. The source file is decomposed into preprocessing tokens<sup><a href="#note7"><b>7)</b></a></sup> and sequences of
white-space characters (including comments). A source file shall not end in a
partial preprocessing token or in a partial comment. Each comment is replaced by
one space character. New-line characters are retained. Whether each nonempty
5. Each source character set member and escape sequence in character constants and
string literals is converted to the corresponding member of the execution character
set; if there is no corresponding member, it is converted to an implementation-
- defined member other than the null (wide) character.8)
+ defined member other than the null (wide) character.<sup><a href="#note8"><b>8)</b></a></sup>
6. Adjacent string literal tokens are concatenated.
7. White-space characters separating tokens are no longer significant. Each
preprocessing token is converted into a token. The resulting tokens are
-
7) As described in <a href="#6.4">6.4</a>, the process of dividing a source file's characters into preprocessing tokens is
+
<sup><a name="note7" href="#note7"><b>7)</b></a></sup> As described in <a href="#6.4">6.4</a>, the process of dividing a source file's characters into preprocessing tokens is
context-dependent. For example, see the handling of < within a #include preprocessing directive.
-8) An implementation need not convert all non-corresponding source characters to the same execution
+<sup><a name="note8" href="#note8"><b>8)</b></a></sup> An implementation need not convert all non-corresponding source characters to the same execution
character.
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#p11" href="p11">page 11</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p11" href="#p11">page 11</a>] (<a href="#Contents">Contents</a>)
<a name="5.1.1.3" href="#5.1.1.3"><b> 5.1.1.3 Diagnostics</b></a>
1 A conforming implementation shall produce at least one diagnostic message (identified in
an implementation-defined manner) if a preprocessing translation unit or translation unit
contains a violation of any syntax rule or constraint, even if the behavior is also explicitly
specified as undefined or implementation-defined. Diagnostic messages need not be
- produced in other circumstances.9)
+ produced in other circumstances.<sup><a href="#note9"><b>9)</b></a></sup>
2 EXAMPLE An implementation shall issue a diagnostic for the translation unit:
char i;
int i;
- 9) The intent is that an implementation should identify the nature of, and where possible localize, each
+ <sup><a name="note9" href="#note9"><b>9)</b></a></sup> The intent is that an implementation should identify the nature of, and where possible localize, each
violation. Of course, an implementation is free to produce any number of diagnostics as long as a
valid program is still correctly translated. It may also successfully translate an invalid program.
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+[<a name="
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<a name="5.1.2.2.1" href="#5.1.2.2.1"><b> 5.1.2.2.1 Program startup</b></a>
1 The function called at program startup is named main. The implementation declares no
or with two parameters (referred to here as argc and argv, though any names may be
used, as they are local to the function in which they are declared):
int main(int argc, char *argv[]) { /* ... */ }
- or equivalent;10) or in some other implementation-defined manner.
+ or equivalent;<sup><a href="#note10"><b>10)</b></a></sup> or in some other implementation-defined manner.
2 If they are declared, the parameters to the main function shall obey the following
constraints:
-- The value of argc shall be nonnegative.
- 10) Thus, int can be replaced by a typedef name defined as int, or the type of argv can be written as
+ <sup><a name="note10" href="#note10"><b>10)</b></a></sup> Thus, int can be replaced by a typedef name defined as int, or the type of argv can be written as
char ** argv, and so on.
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+[<a name="
p13" href="#p13">page 13</a>] (<a href="#Contents">Contents</a>)
<a name="5.1.2.2.3" href="#5.1.2.2.3"><b> 5.1.2.2.3 Program termination</b></a>
1 If the return type of the main function is a type compatible with int, a return from the
initial call to the main function is equivalent to calling the exit function with the value
- returned by the main function as its argument;11) reaching the } that terminates the
+ returned by the main function as its argument;<sup><a href="#note11"><b>11)</b></a></sup> reaching the } that terminates the
main function returns a value of 0. If the return type is not compatible with int, the
termination status returned to the host environment is unspecified.
Forward references: definition of terms (<a href="#7.1.1">7.1.1</a>), the exit function (<a href="#7.22.4.4">7.22.4.4</a>).
1 The semantic descriptions in this International Standard describe the behavior of an
abstract machine in which issues of optimization are irrelevant.
2 Accessing a volatile object, modifying an object, modifying a file, or calling a function
- that does any of those operations are all side effects,12) which are changes in the state of
+ that does any of those operations are all side effects,<sup><a href="#note12"><b>12)</b></a></sup> which are changes in the state of
the execution environment. Evaluation of an expression in general includes both value
computations and initiation of side effects. Value computation for an lvalue expression
includes determining the identity of the designated object.
shall precede the execution of B. (Conversely, if A is sequenced before B, then B is
sequenced after A.) If A is not sequenced before or after B, then A and B are
unsequenced. Evaluations A and B are indeterminately sequenced when A is sequenced
- either before or after B, but it is unspecified which.13) The presence of a sequence point
+ either before or after B, but it is unspecified which.<sup><a href="#note13"><b>13)</b></a></sup> The presence of a sequence point
between the evaluation of expressions A and B implies that every value computation and
side effect associated with A is sequenced before every value computation and side effect
associated with B. (A summary of the sequence points is given in <a href="#C">annex C</a>.)
actual implementation need not evaluate part of an expression if it can deduce that its
value is not used and that no needed side effects are produced (including any caused by
-
11) In accordance with <a href="#6.2.4">6.2.4</a>, the lifetimes of objects with automatic storage duration declared in main
+
<sup><a name="note11" href="#note11"><b>11)</b></a></sup> In accordance with <a href="#6.2.4">6.2.4</a>, the lifetimes of objects with automatic storage duration declared in main
will have ended in the former case, even where they would not have in the latter.
- 12) The IEC 60559 standard for binary floating-point arithmetic requires certain user-accessible status
+ <sup><a name="note12" href="#note12"><b>12)</b></a></sup> The IEC 60559 standard for binary floating-point arithmetic requires certain user-accessible status
flags and control modes. Floating-point operations implicitly set the status flags; modes affect result
values of floating-point operations. Implementations that support such floating-point state are
required to regard changes to it as side effects -- see <a href="#F">annex F</a> for details. The floating-point
environment library <a href="#7.6"><fenv.h></a> provides a programming facility for indicating when these side
effects matter, freeing the implementations in other cases.
- 13) The executions of unsequenced evaluations can interleave. Indeterminately sequenced evaluations
+ <sup><a name="note13" href="#note13"><b>13)</b></a></sup> The executions of unsequenced evaluations can interleave. Indeterminately sequenced evaluations
cannot interleave, but can be executed in any order.
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+[<a name="
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calling a function or accessing a volatile object).
5 When the processing of the abstract machine is interrupted by receipt of a signal, the
overflow, or with overflow wrapping silently to produce the correct result, the actual execution need only
produce the same result, possibly omitting the promotions.
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#p15" href="p15">page 15</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p15" href="#p15">page 15</a>] (<a href="#Contents">Contents</a>)
12 EXAMPLE 3 Similarly, in the fragment
float f1, f2;
f1 = f2 * d;
the multiplication may be executed using single-precision arithmetic if the implementation can ascertain
that the result would be the same as if it were executed using double-precision arithmetic (for example, if d
- were replaced by the constant <a href="#2.0">2.0</a>, which has type double).
+ were replaced by the constant 2.0, which has type double).
13 EXAMPLE 4 Implementations employing wide registers have to take care to honor appropriate
semantics. Values are independent of whether they are represented in a register or in memory. For
/* ... */
x = (x * y) * z; // not equivalent to x *= y * z;
z = (x - y) + y ; // not equivalent to z = x;
- z = x + x * y; // not equivalent to z = x * (<a href="#1.0">1.0</a> + y);
- y = x / <a href="#5.0">5.0</a>; // not equivalent to y = x * 0.2;
+ z = x + x * y; // not equivalent to z = x * (1.0 + y);
+ y = x / 5.0; // not equivalent to y = x * 0.2;
15 EXAMPLE 6 To illustrate the grouping behavior of expressions, in the following fragment
int a, b;
since if the values for a and b were, respectively, -32754 and -15, the sum a + b would produce a trap
while the original expression would not; nor can the expression be rewritten either as
-
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+[<a name="p16" href="#p16">page 16</a>] (<a href="#Contents">Contents</a>)
a = ((a + 32765) + b);
or
1 Under a hosted implementation, a program can have more than one thread of execution
(or thread) running concurrently. The execution of each thread proceeds as defined by
the remainder of this standard. The execution of the entire program consists of an
- execution of all of its threads.14) Under a freestanding implementation, it is
+ execution of all of its threads.<sup><a href="#note14"><b>14)</b></a></sup> Under a freestanding implementation, it is
implementation-defined whether a program can have more than one thread of execution.
2 The value of an object visible to a thread T at a particular point is the initial value of the
object, a value stored in the object by T , or a value stored in the object by another thread,
- 14) The execution can usually be viewed as an interleaving of all of the threads. However, some kinds of
+ <sup><a name="note14" href="#note14"><b>14)</b></a></sup> The execution can usually be viewed as an interleaving of all of the threads. However, some kinds of
atomic operations, for example, allow executions inconsistent with a simple interleaving as described
below.
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+[<a name="
p17" href="#p17">page 17</a>] (<a href="#Contents">Contents</a>)
5 The library defines a number of atomic operations (<a href="#7.17">7.17</a>) and operations on mutexes
(<a href="#7.25.4">7.25.4</a>) that are specially identified as synchronization operations. These operations play
another. For atomic variables, the definition is clear. All operations on a given mutex occur in a single total
order. Each mutex acquisition ''reads the value written'' by the last mutex release.
-14 An evaluation A carries a dependency 15) to an evaluation B if:
+14 An evaluation A carries a dependency <sup><a href="#note15"><b>15)</b></a></sup> to an evaluation B if:
- 15) The ''carries a dependency'' relation is a subset of the ''sequenced before'' relation, and is similarly
+ <sup><a name="note15" href="#note15"><b>15)</b></a></sup> The ''carries a dependency'' relation is a subset of the ''sequenced before'' relation, and is similarly
strictly intra-thread.
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+[<a name="
p18" href="#p18">page 18</a>] (<a href="#Contents">Contents</a>)
-- the value of A is used as an operand of B, unless:
o B is an invocation of the kill_dependency macro,
-- A writes a scalar object or bit-field M, B reads from M the value written by A, and A
is sequenced before B, or
-- for some evaluation X, A carries a dependency to X and X carries a dependency to B.
-15 An evaluation A is dependency-ordered before16) an evaluation B if:
+15 An evaluation A is dependency-ordered before<sup><a href="#note16"><b>16)</b></a></sup> an evaluation B if:
-- A performs a release operation on an atomic object M, and B performs a consume
operation on M and reads a value written by any side effect in the release sequence
headed by A, or
- 16) The ''dependency-ordered before'' relation is analogous to the ''synchronizes with'' relation, but uses
+ <sup><a name="note16" href="#note16"><b>16)</b></a></sup> The ''dependency-ordered before'' relation is analogous to the ''synchronizes with'' relation, but uses
release/consume in place of release/acquire.
-[<a name="
#p19" href="p19">page 19</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p19" href="#p19">page 19</a>] (<a href="#Contents">Contents</a>)
19 A visible side effect A on an object M with respect to a value computation B of M
satisfies the conditions:
program semantics. In fact, most single-threaded program transformations continue to be allowed, since
any program that behaves differently as a result must contain undefined behavior.
-[<a name="
#p20" href="p20">page 20</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p20" href="#p20">page 20</a>] (<a href="#Contents">Contents</a>)
27 NOTE 13 Compiler transformations that introduce assignments to a potentially shared memory location
that would not be modified by the abstract machine are generally precluded by this standard, since such an
machine with well-defined semantics for data races. They would be invalid for a hypothetical machine that
is not tolerant of races or provides hardware race detection.
-
-
-
-[<a name="#p21" href="p21">page 21</a>] (<a href="#Contents">Contents</a>)
+[<a name="p21" href="#p21">page 21</a>] (<a href="#Contents">Contents</a>)
<a name="5.2" href="#5.2"><b> 5.2 Environmental considerations</b></a>
<a name="5.2.1" href="#5.2.1"><b> 5.2.1 Character sets</b></a>
other characters are encountered in a source file (except in an identifier, a character
constant, a string literal, a header name, a comment, or a preprocessing token that is never
-[<a name="
#p22" href="p22">page 22</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p22" href="#p22">page 22</a>] (<a href="#Contents">Contents</a>)
converted to a token), the behavior is undefined.
4 A letter is an uppercase letter or a lowercase letter as defined above; in this International
preprocessing directives (<a href="#6.10">6.10</a>), string literals (<a href="#6.4.5">6.4.5</a>), comments (<a href="#6.4.9">6.4.9</a>), string (<a href="#7.1.1">7.1.1</a>).
<a name="5.2.1.1" href="#5.2.1.1"><b> 5.2.1.1 Trigraph sequences</b></a>
1 Before any other processing takes place, each occurrence of one of the following
- sequences of three characters (called trigraph sequences17)) is replaced with the
+ sequences of three characters (called trigraph sequences<sup><a href="#note17"><b>17)</b></a></sup>) is replaced with the
corresponding single character.
??= # ??) ] ??! |
??( [ ??' ^ ??> }
-- The presence, meaning, and representation of any additional members is locale-
specific.
- 17) The trigraph sequences enable the input of characters that are not defined in the Invariant Code Set as
+ <sup><a name="note17" href="#note17"><b>17)</b></a></sup> The trigraph sequences enable the input of characters that are not defined in the Invariant Code Set as
described in ISO/IEC 646, which is a subset of the seven-bit US ASCII code set.
-[<a name="
#p23" href="p23">page 23</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p23" href="#p23">page 23</a>] (<a href="#Contents">Contents</a>)
-- A multibyte character set may have a state-dependent encoding, wherein each
sequence of multibyte characters begins in an initial shift state and enters other
tabulation position, the behavior of the display device is unspecified.
\v (vertical tab) Moves the active position to the initial position of the next vertical
tabulation position. If the active position is at or past the last defined vertical
-[<a name="#p24" href="p24">page 24</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p24" href="#p24">page 24</a>] (<a href="#Contents">Contents</a>)
tabulation position, the behavior of the display device is unspecified.
3 Each of these escape sequences shall produce a unique implementation-defined value
discussed in clause 7.
<a name="5.2.4.1" href="#5.2.4.1"><b> 5.2.4.1 Translation limits</b></a>
1 The implementation shall be able to translate and execute at least one program that
- contains at least one instance of every one of the following limits:18)
+ contains at least one instance of every one of the following limits:<sup><a href="#note18"><b>18)</b></a></sup>
-- 127 nesting levels of blocks
-- 63 nesting levels of conditional inclusion
-- 12 pointer, array, and function declarators (in any combinations) modifying an
specifying a short identifier of 0000FFFF or less is considered 6 characters, each
- 18) Implementations should avoid imposing fixed translation limits whenever possible.
+ <sup><a name="note18" href="#note18"><b>18)</b></a></sup> Implementations should avoid imposing fixed translation limits whenever possible.
-[<a name="
#p25" href="p25">page 25</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p25" href="#p25">page 25</a>] (<a href="#Contents">Contents</a>)
universal character name specifying a short identifier of 00010000 or more is
considered 10 characters, and each extended source character is considered the same
- number of characters as the corresponding universal character name, if any)19)
+ number of characters as the corresponding universal character name, if any)<sup><a href="#note19"><b>19)</b></a></sup>
-- 4095 external identifiers in one translation unit
-- 511 identifiers with block scope declared in one block
-- 4095 macro identifiers simultaneously defined in one preprocessing translation unit
promotions. Their implementation-defined values shall be equal or greater in magnitude
-
19) See ''future language directions'' (<a href="#6.11.3">6.11.3</a>).
+
<sup><a name="note19" href="#note19"><b>19)</b></a></sup> See ''future language directions'' (<a href="#6.11.3">6.11.3</a>).
-[<a name="
#p26" href="p26">page 26</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p26" href="#p26">page 26</a>] (<a href="#Contents">Contents</a>)
(absolute value) to those shown, with the same sign.
-- number of bits for smallest object that is not a bit-field (byte)
-- maximum value for an object of type unsigned long int
ULONG_MAX 4294967295 // 232 - 1
-
-[<a name="#p27" href="p27">page 27</a>] (<a href="#Contents">Contents</a>)
+[<a name="p27" href="#p27">page 27</a>] (<a href="#Contents">Contents</a>)
-- minimum value for an object of type long long int
LLONG_MIN -9223372036854775807 // -(263 - 1)
expression, the value of CHAR_MIN shall be the same as that of SCHAR_MIN and the
value of CHAR_MAX shall be the same as that of SCHAR_MAX. Otherwise, the value of
CHAR_MIN shall be 0 and the value of CHAR_MAX shall be the same as that of
- UCHAR_MAX.20) The value UCHAR_MAX shall equal 2CHAR_BIT - 1.
+ UCHAR_MAX.<sup><a href="#note20"><b>20)</b></a></sup> The value UCHAR_MAX shall equal 2CHAR_BIT - 1.
Forward references: representations of types (<a href="#6.2.6">6.2.6</a>), conditional inclusion (<a href="#6.10.1">6.10.1</a>).
<a name="5.2.4.2.2" href="#5.2.4.2.2"><b> 5.2.4.2.2 Characteristics of floating types <float.h></b></a>
1 The characteristics of floating types are defined in terms of a model that describes a
representation of floating-point numbers and values that provide information about an
- implementation's floating-point arithmetic.21) The following parameters are used to
+ implementation's floating-point arithmetic.<sup><a href="#note21"><b>21)</b></a></sup> The following parameters are used to
define the model for each floating-point type:
s sign ((+-)1)
b base or radix of exponent representation (an integer > 1)
signaling NaN generally raises a floating-point exception when occurring as an
-
20) See <a href="#6.2.5">6.2.5</a>.
- 21) The floating-point model is intended to clarify the description of each floating-point characteristic and
+
<sup><a name="note20" href="#note20"><b>20)</b></a></sup> See <a href="#6.2.5">6.2.5</a>.
+ <sup><a name="note21" href="#note21"><b>21)</b></a></sup> The floating-point model is intended to clarify the description of each floating-point characteristic and
does not require the floating-point arithmetic of the implementation to be identical.
-[<a name="
#p28" href="p28">page 28</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p28" href="#p28">page 28</a>] (<a href="#Contents">Contents</a>)
- arithmetic operand.22)
+ arithmetic operand.<sup><a href="#note22"><b>22)</b></a></sup>
4 An implementation may give zero and values that are not floating-point numbers (such as
infinities and NaNs) a sign or may leave them unsigned. Wherever such values are
unsigned, any requirement in this International Standard to retrieve the sign shall produce
point model representation is provided for all values except FLT_EVAL_METHOD and
FLT_ROUNDS.
8 The rounding mode for floating-point addition is characterized by the implementation-
- defined value of FLT_ROUNDS:23)
+ defined value of FLT_ROUNDS:<sup><a href="#note23"><b>23)</b></a></sup>
-1 indeterminable
0 toward zero
1 to nearest
behavior.
- 22) IEC 60559:1989 specifies quiet and signaling NaNs. For implementations that do not support
+ <sup><a name="note22" href="#note22"><b>22)</b></a></sup> IEC 60559:1989 specifies quiet and signaling NaNs. For implementations that do not support
IEC 60559:1989, the terms quiet NaN and signaling NaN are intended to apply to encodings with
similar behavior.
- 23) Evaluation of FLT_ROUNDS correctly reflects any execution-time change of rounding mode through
+ <sup><a name="note23" href="#note23"><b>23)</b></a></sup> Evaluation of FLT_ROUNDS correctly reflects any execution-time change of rounding mode through
the function fesetround in <a href="#7.6"><fenv.h></a>.
-[<a name="
#p29" href="p29">page 29</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p29" href="#p29">page 29</a>] (<a href="#Contents">Contents</a>)
9 Except for assignment and cast (which remove all extra range and precision), the values
yielded by operators with floating operands and values subject to the usual arithmetic
conversions and of floating constants are evaluated to a format whose range and precision
may be greater than required by the type. The use of evaluation formats is characterized
- by the implementation-defined value of FLT_EVAL_METHOD:24)
+ by the implementation-defined value of FLT_EVAL_METHOD:<sup><a href="#note24"><b>24)</b></a></sup>
-1 indeterminable;
0 evaluate all operations and constants just to the range and precision of the
type;
10 The presence or absence of subnormal numbers is characterized by the implementation-
defined values of FLT_HAS_SUBNORM, DBL_HAS_SUBNORM, and
LDBL_HAS_SUBNORM:
- -1 indeterminable25)
- 0 absent26) (type does not support subnormal numbers)
+ -1 indeterminable<sup><a href="#note25"><b>25)</b></a></sup>
+ 0 absent<sup><a href="#note26"><b>26)</b></a></sup> (type does not support subnormal numbers)
1 present (type does support subnormal numbers)
11 The values given in the following list shall be replaced by constant expressions with
implementation-defined values that are greater or equal in magnitude (absolute value) to
- 24) The evaluation method determines evaluation formats of expressions involving all floating types, not
+ <sup><a name="note24" href="#note24"><b>24)</b></a></sup> The evaluation method determines evaluation formats of expressions involving all floating types, not
just real types. For example, if FLT_EVAL_METHOD is 1, then the product of two float
_Complex operands is represented in the double _Complex format, and its parts are evaluated to
double.
- 25) Characterization as indeterminable is intended if floating-point operations do not consistently interpret
+ <sup><a name="note25" href="#note25"><b>25)</b></a></sup> Characterization as indeterminable is intended if floating-point operations do not consistently interpret
subnormal representations as zero, nor as nonzero.
- 26) Characterization as absent is intended if no floating-point operations produce subnormal results from
+ <sup><a name="note26" href="#note26"><b>26)</b></a></sup> Characterization as absent is intended if no floating-point operations produce subnormal results from
non-subnormal inputs, even if the type format includes representations of subnormal numbers.
-[<a name="
#p30" href="p30">page 30</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p30" href="#p30">page 30</a>] (<a href="#Contents">Contents</a>)
-- number of base-FLT_RADIX digits in the floating-point significand, p
FLT_MANT_DIG
DBL_MIN_EXP
LDBL_MIN_EXP
-
-
-
-[<a name="#p31" href="p31">page 31</a>] (<a href="#Contents">Contents</a>)
+[<a name="p31" href="#p31">page 31</a>] (<a href="#Contents">Contents</a>)
-- minimum negative integer such that 10 raised to that power is in the range of
normalized floating-point numbers, [^log10 b emin -1 ^]
DBL_MIN 1E-37
LDBL_MIN 1E-37
+[<a name="p32" href="#p32">page 32</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p32" href="p32">page 32</a>] (<a href="#Contents">Contents</a>)
-
- -- minimum positive floating-point number27)
+ -- minimum positive floating-point number<sup><a href="#note27"><b>27)</b></a></sup>
FLT_TRUE_MIN 1E-37
DBL_TRUE_MIN 1E-37
LDBL_TRUE_MIN 1E-37
FLT_MAX_10_EXP +38
16 EXAMPLE 2 The following describes floating-point representations that also meet the requirements for
- single-precision and double-precision numbers in IEC 60559,28) and the appropriate values in a
+ single-precision and double-precision numbers in IEC 60559,<sup><a href="#note28"><b>28)</b></a></sup> and the appropriate values in a
<a href="#7.7"><float.h></a> header for types float and double:
24
x f = s2e (Sum) f k 2-k ,
FLT_DECIMAL_DIG 9
- 27) If the presence or absence of subnormal numbers is indeterminable, then the value is intended to be a
+ <sup><a name="note27" href="#note27"><b>27)</b></a></sup> If the presence or absence of subnormal numbers is indeterminable, then the value is intended to be a
positive number no greater than the minimum normalized positive number for the type.
- 28) The floating-point model in that standard sums powers of b from zero, so the values of the exponent
+ <sup><a name="note28" href="#note28"><b>28)</b></a></sup> The floating-point model in that standard sums powers of b from zero, so the values of the exponent
limits are one less than shown here.
-[<a name="
#p33" href="p33">page 33</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p33" href="#p33">page 33</a>] (<a href="#Contents">Contents</a>)
FLT_DIG 6
FLT_MIN_EXP -125
(<a href="#7.28">7.28</a>), floating-point environment <a href="#7.6"><fenv.h></a> (<a href="#7.6">7.6</a>), general utilities <a href="#7.22"><stdlib.h></a>
(<a href="#7.22">7.22</a>), input/output <a href="#7.21"><stdio.h></a> (<a href="#7.21">7.21</a>), mathematics <a href="#7.12"><math.h></a> (<a href="#7.12">7.12</a>).
-
-
-
-[<a name="#p34" href="p34">page 34</a>] (<a href="#Contents">Contents</a>)
+[<a name="p34" href="#p34">page 34</a>] (<a href="#Contents">Contents</a>)
<a name="6" href="#6"><b> 6. Language</b></a>
a function definition, the identifier has block scope, which terminates at the end of the
associated block. If the declarator or type specifier that declares the identifier appears
-[<a name="
#p35" href="p35">page 35</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p35" href="#p35">page 35</a>] (<a href="#Contents">Contents</a>)
within the list of parameter declarations in a function prototype (not part of a function
definition), the identifier has function prototype scope, which terminates at the end of the
source file inclusion (<a href="#6.10.2">6.10.2</a>), statements (<a href="#6.8">6.8</a>).
<a name="6.2.2" href="#6.2.2"><b> 6.2.2 Linkages of identifiers</b></a>
1 An identifier declared in different scopes or in the same scope more than once can be
- made to refer to the same object or function by a process called linkage.29) There are
+ made to refer to the same object or function by a process called linkage.<sup><a href="#note29"><b>29)</b></a></sup> There are
three kinds of linkage: external, internal, and none.
2 In the set of translation units and libraries that constitutes an entire program, each
declaration of a particular identifier with external linkage denotes the same object or
linkage denotes the same object or function. Each declaration of an identifier with no
linkage denotes a unique entity.
3 If the declaration of a file scope identifier for an object or a function contains the storage-
- class specifier static, the identifier has internal linkage.30)
+ class specifier static, the identifier has internal linkage.<sup><a href="#note30"><b>30)</b></a></sup>
- 29) There is no linkage between different identifiers.
+ <sup><a name="note29" href="#note29"><b>29)</b></a></sup> There is no linkage between different identifiers.
-[<a name="
#p36" href="p36">page 36</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p36" href="#p36">page 36</a>] (<a href="#Contents">Contents</a>)
4 For an identifier declared with the storage-class specifier extern in a scope in which a
- prior declaration of that identifier is visible,31) if the prior declaration specifies internal or
+ prior declaration of that identifier is visible,<sup><a href="#note31"><b>31)</b></a></sup> if the prior declaration specifies internal or
external linkage, the linkage of the identifier at the later declaration is the same as the
linkage specified at the prior declaration. If no prior declaration is visible, or if the prior
declaration specifies no linkage, then the identifier has external linkage.
translation unit, the syntactic context disambiguates uses that refer to different entities.
Thus, there are separate name spaces for various categories of identifiers, as follows:
-- label names (disambiguated by the syntax of the label declaration and use);
- -- the tags of structures, unions, and enumerations (disambiguated by following any32)
+ -- the tags of structures, unions, and enumerations (disambiguated by following any<sup><a href="#note32"><b>32)</b></a></sup>
of the keywords struct, union, or enum);
-- the members of structures or unions; each structure or union has a separate name
space for its members (disambiguated by the type of the expression used to access the
structure and union specifiers (<a href="#6.7.2.1">6.7.2.1</a>), structure and union members (<a href="#6.5.2.3">6.5.2.3</a>), tags
(<a href="#6.7.2.3">6.7.2.3</a>), the goto statement (<a href="#6.8.6.1">6.8.6.1</a>).
- 30) A function declaration can contain the storage-class specifier static only if it is at file scope; see
-<a name="6.7.1" href="#6.7.1"><b> 6.7.1.</b></a>
-
31) As specified in <a href="#6.2.1">6.2.1</a>, the later declaration might hide the prior declaration.
- 32) There is only one name space for tags even though three are possible.
+ <sup><a name="note30" href="#note30"><b>30)</b></a></sup> A function declaration can contain the storage-class specifier static only if it is at file scope; see
+ <a href="#6.7.1">6.7.1</a>.
+
<sup><a name="note31" href="#note31"><b>31)</b></a></sup> As specified in <a href="#6.2.1">6.2.1</a>, the later declaration might hide the prior declaration.
+ <sup><a name="note32" href="#note32"><b>32)</b></a></sup> There is only one name space for tags even though three are possible.
-[<a name="
#p37" href="p37">page 37</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p37" href="#p37">page 37</a>] (<a href="#Contents">Contents</a>)
<a name="6.2.4" href="#6.2.4"><b> 6.2.4 Storage durations of objects</b></a>
1 An object has a storage duration that determines its lifetime. There are four storage
durations: static, thread, automatic, and allocated. Allocated storage is described in
-<a name="7.22.3" href="#7.22.3"><b> 7.22.3.</b></a>
+ <a href="#7.22.3">7.22.3</a>.
2 The lifetime of an object is the portion of program execution during which storage is
- guaranteed to be reserved for it. An object exists, has a constant address,33) and retains
- its last-stored value throughout its lifetime.34) If an object is referred to outside of its
+ guaranteed to be reserved for it. An object exists, has a constant address,<sup><a href="#note33"><b>33)</b></a></sup> and retains
+ its last-stored value throughout its lifetime.<sup><a href="#note34"><b>34)</b></a></sup> If an object is referred to outside of its
lifetime, the behavior is undefined. The value of a pointer becomes indeterminate when
the object it points to (or just past) reaches the end of its lifetime.
3 An object whose identifier is declared without the storage-class specifier
- 33) The term ''constant address'' means that two pointers to the object constructed at possibly different
+ <sup><a name="note33" href="#note33"><b>33)</b></a></sup> The term ''constant address'' means that two pointers to the object constructed at possibly different
times will compare equal. The address may be different during two different executions of the same
program.
- 34) In the case of a volatile object, the last store need not be explicit in the program.
+ <sup><a name="note34" href="#note34"><b>34)</b></a></sup> In the case of a volatile object, the last store need not be explicit in the program.
-[<a name="
#p38" href="p38">page 38</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p38" href="#p38">page 38</a>] (<a href="#Contents">Contents</a>)
7 For such an object that does have a variable length array type, its lifetime extends from
the declaration of the object until execution of the program leaves the scope of the
- declaration.35) If the scope is entered recursively, a new instance of the object is created
+ declaration.<sup><a href="#note35"><b>35)</b></a></sup> If the scope is entered recursively, a new instance of the object is created
each time. The initial value of the object is indeterminate.
8 A non-lvalue expression with structure or union type, where the structure or union
contains a member with array type (including, recursively, members of all contained
structures and unions) refers to an object with automatic storage duration and temporary
- lifetime.36) Its lifetime begins when the expression is evaluated and its initial value is the
+ lifetime.<sup><a href="#note36"><b>36)</b></a></sup> Its lifetime begins when the expression is evaluated and its initial value is the
value of the expression. Its lifetime ends when the evaluation of the containing full
expression or full declarator ends. Any attempt to modify an object with temporary
lifetime results in undefined behavior.
are partitioned into object types (types that describe objects) and function types (types
that describe functions). At various points within a translation unit an object type may be
incomplete (lacking sufficient information to determine the size of objects of that type) or
- complete (having sufficient information).37)
+ complete (having sufficient information).<sup><a href="#note37"><b>37)</b></a></sup>
2 An object declared as type _Bool is large enough to store the values 0 and 1.
3 An object declared as type char is large enough to store any member of the basic
execution character set. If a member of the basic execution character set is stored in a
4 There are five standard signed integer types, designated as signed char, short
int, int, long int, and long long int. (These and other types may be
designated in several additional ways, as described in <a href="#6.7.2">6.7.2</a>.) There may also be
- implementation-defined extended signed integer types.38) The standard and extended
- signed integer types are collectively called signed integer types.39)
+ implementation-defined extended signed integer types.<sup><a href="#note38"><b>38)</b></a></sup> The standard and extended
+ signed integer types are collectively called signed integer types.<sup><a href="#note39"><b>39)</b></a></sup>
- 35) Leaving the innermost block containing the declaration, or jumping to a point in that block or an
+ <sup><a name="note35" href="#note35"><b>35)</b></a></sup> Leaving the innermost block containing the declaration, or jumping to a point in that block or an
embedded block prior to the declaration, leaves the scope of the declaration.
- 36) The address of such an object is taken implicitly when an array member is accessed.
- 37) A type may be incomplete or complete throughout an entire translation unit, or it may change states at
+ <sup><a name="note36" href="#note36"><b>36)</b></a></sup> The address of such an object is taken implicitly when an array member is accessed.
+ <sup><a name="note37" href="#note37"><b>37)</b></a></sup> A type may be incomplete or complete throughout an entire translation unit, or it may change states at
different points within a translation unit.
-[<a name="
#p39" href="p39">page 39</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p39" href="#p39">page 39</a>] (<a href="#Contents">Contents</a>)
5 An object declared as type signed char occupies the same amount of storage as a
''plain'' char object. A ''plain'' int object has the natural size suggested by the
types are the standard unsigned integer types. The unsigned integer types that
correspond to the extended signed integer types are the extended unsigned integer types.
The standard and extended unsigned integer types are collectively called unsigned integer
- types.40)
+ types.<sup><a href="#note40"><b>40)</b></a></sup>
7 The standard signed integer types and standard unsigned integer types are collectively
called the standard integer types, the extended signed integer types and extended
unsigned integer types are collectively called the extended integer types.
subrange of the values of the other type.
9 The range of nonnegative values of a signed integer type is a subrange of the
corresponding unsigned integer type, and the representation of the same value in each
- type is the same.41) A computation involving unsigned operands can never overflow,
+ type is the same.<sup><a href="#note41"><b>41)</b></a></sup> A computation involving unsigned operands can never overflow,
because a result that cannot be represented by the resulting unsigned integer type is
reduced modulo the number that is one greater than the largest value that can be
represented by the resulting type.
10 There are three real floating types, designated as float, double, and long
- double.42) The set of values of the type float is a subset of the set of values of the
+ double.<sup><a href="#note42"><b>42)</b></a></sup> The set of values of the type float is a subset of the set of values of the
type double; the set of values of the type double is a subset of the set of values of the
type long double.
- 38) Implementation-defined keywords shall have the form of an identifier reserved for any use as
+ <sup><a name="note38" href="#note38"><b>38)</b></a></sup> Implementation-defined keywords shall have the form of an identifier reserved for any use as
described in <a href="#7.1.3">7.1.3</a>.
- 39) Therefore, any statement in this Standard about signed integer types also applies to the extended
+ <sup><a name="note39" href="#note39"><b>39)</b></a></sup> Therefore, any statement in this Standard about signed integer types also applies to the extended
signed integer types.
- 40) Therefore, any statement in this Standard about unsigned integer types also applies to the extended
+ <sup><a name="note40" href="#note40"><b>40)</b></a></sup> Therefore, any statement in this Standard about unsigned integer types also applies to the extended
unsigned integer types.
- 41) The same representation and alignment requirements are meant to imply interchangeability as
+ <sup><a name="note41" href="#note41"><b>41)</b></a></sup> The same representation and alignment requirements are meant to imply interchangeability as
arguments to functions, return values from functions, and members of unions.
-
42) See ''future language directions'' (<a href="#6.11.1">6.11.1</a>).
+
<sup><a name="note42" href="#note42"><b>42)</b></a></sup> See ''future language directions'' (<a href="#6.11.1">6.11.1</a>).
-[<a name="
#p40" href="p40">page 40</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p40" href="#p40">page 40</a>] (<a href="#Contents">Contents</a>)
11 There are three complex types, designated as float _Complex, double
- _Complex, and long double _Complex.43) (Complex types are a conditional
+ _Complex, and long double _Complex.<sup><a href="#note43"><b>43)</b></a></sup> (Complex types are a conditional
feature that implementations need not support; see <a href="#6.10.8.3">6.10.8.3</a>.) The real floating and
complex types are collectively called the floating types.
12 For each floating type there is a corresponding real type, which is always a real floating
14 The type char, the signed and unsigned integer types, and the floating types are
collectively called the basic types. The basic types are complete object types. Even if the
implementation defines two or more basic types to have the same representation, they are
- nevertheless different types.44)
+ nevertheless different types.<sup><a href="#note44"><b>44)</b></a></sup>
15 The three types char, signed char, and unsigned char are collectively called
the character types. The implementation shall define char to have the same range,
- representation, and behavior as either signed char or unsigned char.45)
+ representation, and behavior as either signed char or unsigned char.<sup><a href="#note45"><b>45)</b></a></sup>
16 An enumeration comprises a set of named integer constant values. Each distinct
enumeration constitutes a different enumerated type.
17 The type char, the signed and unsigned integer types, and the enumerated types are
-
43) A specification for imaginary types is in <a href="#G">annex G</a>.
- 44) An implementation may define new keywords that provide alternative ways to designate a basic (or
+
<sup><a name="note43" href="#note43"><b>43)</b></a></sup> A specification for imaginary types is in <a href="#G">annex G</a>.
+ <sup><a name="note44" href="#note44"><b>44)</b></a></sup> An implementation may define new keywords that provide alternative ways to designate a basic (or
any other) type; this does not violate the requirement that all basic types be different.
Implementation-defined keywords shall have the form of an identifier reserved for any use as
described in <a href="#7.1.3">7.1.3</a>.
-
45) CHAR_MIN, defined in <a href="#7.10"><limits.h></a>, will have one of the values 0 or SCHAR_MIN, and this can be
+
<sup><a name="note45" href="#note45"><b>45)</b></a></sup> CHAR_MIN, defined in <a href="#7.10"><limits.h></a>, will have one of the values 0 or SCHAR_MIN, and this can be
used to distinguish the two options. Irrespective of the choice made, char is a separate type from the
other two and is not compatible with either.
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+[<a name="
p41" href="#p41">page 41</a>] (<a href="#Contents">Contents</a>)
20 Any number of derived types can be constructed from the object and function types, as
follows:
support; see <a href="#6.10.8.3">6.10.8.3</a>.)
These methods of constructing derived types can be applied recursively.
21 Arithmetic types and pointer types are collectively called scalar types. Array and
- structure types are collectively called aggregate types.46)
+ structure types are collectively called aggregate types.<sup><a href="#note46"><b>46)</b></a></sup>
22 An array type of unknown size is an incomplete type. It is completed, for an identifier of
that type, by specifying the size in a later declaration (with internal or external linkage).
A structure or union type of unknown content (as described in <a href="#6.7.2.3">6.7.2.3</a>) is an incomplete
- 46) Note that aggregate type does not include union type because an object with union type can only
+ <sup><a name="note46" href="#note46"><b>46)</b></a></sup> Note that aggregate type does not include union type because an object with union type can only
contain one member at a time.
-[<a name="
#p42" href="p42">page 42</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p42" href="#p42">page 42</a>] (<a href="#Contents">Contents</a>)
type. It is completed, for all declarations of that type, by declaring the same structure or
union tag with its defining content later in the same scope.
derived type (as noted above in the construction of derived types), or the type itself if the
type consists of no derived types.
26 Any type so far mentioned is an unqualified type. Each unqualified type has several
- qualified versions of its type,47) corresponding to the combinations of one, two, or all
+ qualified versions of its type,<sup><a href="#note47"><b>47)</b></a></sup> corresponding to the combinations of one, two, or all
three of the const, volatile, and restrict qualifiers. The qualified or unqualified
versions of a type are distinct types that belong to the same type category and have the
- same representation and alignment requirements.48) A derived type is not qualified by the
+ same representation and alignment requirements.<sup><a href="#note48"><b>48)</b></a></sup> A derived type is not qualified by the
qualifiers (if any) of the type from which it is derived.
27 Further, there is the _Atomic qualifier. The presence of the _Atomic qualifier
designates an atomic type. The size, representation, and alignment of an atomic type
whereas the type designated as ''const float *'' is not a qualified type -- its type is ''pointer to const-
-
47) See <a href="#6.7.3">6.7.3</a> regarding qualified array and function types.
- 48) The same representation and alignment requirements are meant to imply interchangeability as
+
<sup><a name="note47" href="#note47"><b>47)</b></a></sup> See <a href="#6.7.3">6.7.3</a> regarding qualified array and function types.
+ <sup><a name="note48" href="#note48"><b>48)</b></a></sup> The same representation and alignment requirements are meant to imply interchangeability as
arguments to functions, return values from functions, and members of unions.
-[<a name="
#p43" href="p43">page 43</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p43" href="#p43">page 43</a>] (<a href="#Contents">Contents</a>)
qualified float'' and is a pointer to a qualified type.
the number, order, and encoding of which are either explicitly specified or
implementation-defined.
3 Values stored in unsigned bit-fields and objects of type unsigned char shall be
- represented using a pure binary notation.49)
+ represented using a pure binary notation.<sup><a href="#note49"><b>49)</b></a></sup>
4 Values stored in non-bit-field objects of any other object type consist of n x CHAR_BIT
bits, where n is the size of an object of that type, in bytes. The value may be copied into
an object of type unsigned char [n] (e.g., by memcpy); the resulting set of bytes is
value of an object has such a representation and is read by an lvalue expression that does
not have character type, the behavior is undefined. If such a representation is produced
by a side effect that modifies all or any part of the object by an lvalue expression that
- does not have character type, the behavior is undefined.50) Such a representation is called
+ does not have character type, the behavior is undefined.<sup><a href="#note50"><b>50)</b></a></sup> Such a representation is called
a trap representation.
6 When a value is stored in an object of structure or union type, including in a member
object, the bytes of the object representation that correspond to any padding bytes take
- unspecified values.51) The value of a structure or union object is never a trap
+ unspecified values.<sup><a href="#note51"><b>51)</b></a></sup> The value of a structure or union object is never a trap
- 49) A positional representation for integers that uses the binary digits 0 and 1, in which the values
+ <sup><a name="note49" href="#note49"><b>49)</b></a></sup> A positional representation for integers that uses the binary digits 0 and 1, in which the values
represented by successive bits are additive, begin with 1, and are multiplied by successive integral
powers of 2, except perhaps the bit with the highest position. (Adapted from the American National
Dictionary for Information Processing Systems.) A byte contains CHAR_BIT bits, and the values of
type unsigned char range from 0 to 2
CHAR_BIT
- 1.
- 50) Thus, an automatic variable can be initialized to a trap representation without causing undefined
+ <sup><a name="note50" href="#note50"><b>50)</b></a></sup> Thus, an automatic variable can be initialized to a trap representation without causing undefined
behavior, but the value of the variable cannot be used until a proper value is stored in it.
-[<a name="
#p44" href="p44">page 44</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p44" href="#p44">page 44</a>] (<a href="#Contents">Contents</a>)
representation, even though the value of a member of the structure or union object may be
a trap representation.
representation that do not correspond to that member but do correspond to other members
take unspecified values.
8 Where an operator is applied to a value that has more than one object representation,
- which object representation is used shall not affect the value of the result.52) Where a
+ which object representation is used shall not affect the value of the result.<sup><a href="#note52"><b>52)</b></a></sup> Where a
value is stored in an object using a type that has more than one object representation for
that value, it is unspecified which representation is used, but a trap representation shall
not be generated.
not be any of the latter). If there are N value bits, each bit shall represent a different
power of 2 between 1 and 2 N -1 , so that objects of that type shall be capable of
representing values from 0 to 2 N - 1 using a pure binary representation; this shall be
- known as the value representation. The values of any padding bits are unspecified.53)
+ known as the value representation. The values of any padding bits are unspecified.<sup><a href="#note53"><b>53)</b></a></sup>
2 For signed integer types, the bits of the object representation shall be divided into three
groups: value bits, padding bits, and the sign bit. There need not be any padding bits;
signed char shall not have any padding bits. There shall be exactly one sign bit.
representation of the corresponding unsigned type (if there are M value bits in the signed
type and N in the unsigned type, then M <= N ). If the sign bit is zero, it shall not affect
- 51) Thus, for example, structure assignment need not copy any padding bits.
- 52) It is possible for objects x and y with the same effective type T to have the same value when they are
+ <sup><a name="note51" href="#note51"><b>51)</b></a></sup> Thus, for example, structure assignment need not copy any padding bits.
+ <sup><a name="note52" href="#note52"><b>52)</b></a></sup> It is possible for objects x and y with the same effective type T to have the same value when they are
accessed as objects of type T, but to have different values in other contexts. In particular, if == is
defined for type T, then x == y does not imply that memcmp(&x, &y, sizeof (T)) == 0.
Furthermore, x == y does not necessarily imply that x and y have the same value; other operations
on values of type T may distinguish between them.
- 53) Some combinations of padding bits might generate trap representations, for example, if one padding
+ <sup><a name="note53" href="#note53"><b>53)</b></a></sup> Some combinations of padding bits might generate trap representations, for example, if one padding
bit is a parity bit. Regardless, no arithmetic operation on valid values can generate a trap
representation other than as part of an exceptional condition such as an overflow, and this cannot occur
with unsigned types. All other combinations of padding bits are alternative object representations of
the value specified by the value bits.
-[<a name="
#p45" href="p45">page 45</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p45" href="#p45">page 45</a>] (<a href="#Contents">Contents</a>)
the resulting value. If the sign bit is one, the value shall be modified in one of the
following ways:
and whether a negative zero becomes a normal zero when stored in an object.
4 If the implementation does not support negative zeros, the behavior of the &, |, ^, ~, <<,
and >> operators with operands that would produce such a value is undefined.
-5 The values of any padding bits are unspecified.54) A valid (non-trap) object representation
+5 The values of any padding bits are unspecified.<sup><a href="#note54"><b>54)</b></a></sup> A valid (non-trap) object representation
of a signed integer type where the sign bit is zero is a valid object representation of the
corresponding unsigned type, and shall represent the same value. For any integer type,
the object representation where all the bits are zero shall be a representation of the value
- 54) Some combinations of padding bits might generate trap representations, for example, if one padding
+ <sup><a name="note54" href="#note54"><b>54)</b></a></sup> Some combinations of padding bits might generate trap representations, for example, if one padding
bit is a parity bit. Regardless, no arithmetic operation on valid values can generate a trap
representation other than as part of an exceptional condition such as an overflow. All other
combinations of padding bits are alternative object representations of the value specified by the value
bits.
-[<a name="
#p46" href="p46">page 46</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p46" href="#p46">page 46</a>] (<a href="#Contents">Contents</a>)
<a name="6.2.7" href="#6.2.7"><b> 6.2.7 Compatible type and composite type</b></a>
1 Two types have compatible type if their types are the same. Additional rules for
determining whether two types are compatible are described in <a href="#6.7.2">6.7.2</a> for type specifiers,
- in <a href="#6.7.3">6.7.3</a> for type qualifiers, and in <a href="#6.7.6">6.7.6</a> for declarators.55) Moreover, two structure,
+ in <a href="#6.7.3">6.7.3</a> for type qualifiers, and in <a href="#6.7.6">6.7.6</a> for declarators.<sup><a href="#note55"><b>55)</b></a></sup> Moreover, two structure,
union, or enumerated types declared in separate translation units are compatible if their
tags and members satisfy the following requirements: If one is declared with a tag, the
other shall be declared with the same tag. If both are completed anywhere within their
the composite type is a function prototype with the parameter type list.
- 55) Two types need not be identical to be compatible.
+ <sup><a name="note55" href="#note55"><b>55)</b></a></sup> Two types need not be identical to be compatible.
-[<a name="
#p47" href="p47">page 47</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p47" href="#p47">page 47</a>] (<a href="#Contents">Contents</a>)
-- If both types are function types with parameter type lists, the type of each parameter
in the composite parameter type list is the composite type of the corresponding
parameters.
These rules apply recursively to the types from which the two types are derived.
4 For an identifier with internal or external linkage declared in a scope in which a prior
- declaration of that identifier is visible,56) if the prior declaration specifies internal or
+ declaration of that identifier is visible,<sup><a href="#note56"><b>56)</b></a></sup> if the prior declaration specifies internal or
external linkage, the type of the identifier at the later declaration becomes the composite
type.
Forward references: array declarators (<a href="#6.7.6.2">6.7.6.2</a>).
3 An extended alignment is represented by an alignment greater than
alignof(max_align_t). It is implementation-defined whether any extended
alignments are supported and the contexts in which they are supported. A type having an
- extended alignment requirement is an over-aligned type.57)
+ extended alignment requirement is an over-aligned type.<sup><a href="#note57"><b>57)</b></a></sup>
4 Alignments are represented as values of the type size_t. Valid alignments include only
those values returned by an alignof expression for fundamental types, plus an
additional implementation-defined set of values, which may be empty. Every valid
alignment value shall be a nonnegative integral power of two.
-
56) As specified in <a href="#6.2.1">6.2.1</a>, the later declaration might hide the prior declaration.
- 57) Every over-aligned type is, or contains, a structure or union type with a member to which an extended
+
<sup><a name="note56" href="#note56"><b>56)</b></a></sup> As specified in <a href="#6.2.1">6.2.1</a>, the later declaration might hide the prior declaration.
+ <sup><a name="note57" href="#note57"><b>57)</b></a></sup> Every over-aligned type is, or contains, a structure or union type with a member to which an extended
alignment has been applied.
-[<a name="
#p48" href="p48">page 48</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p48" href="#p48">page 48</a>] (<a href="#Contents">Contents</a>)
5 Alignments have an order from weaker to stronger or stricter alignments. Stricter
alignments have larger alignment values. An address that satisfies an alignment
-- Two alignments are different when their numeric values are not equal.
-- When an alignment is larger than another it represents a stricter alignment.
-
-
-
-[<a name="#p49" href="p49">page 49</a>] (<a href="#Contents">Contents</a>)
+[<a name="p49" href="#p49">page 49</a>] (<a href="#Contents">Contents</a>)
<a name="6.3" href="#6.3"><b> 6.3 Conversions</b></a>
1 Several operators convert operand values from one type to another automatically. This
2 The following may be used in an expression wherever an int or unsigned int may
be used:
-[<a name="
#p50" href="p50">page 50</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p50" href="#p50">page 50</a>] (<a href="#Contents">Contents</a>)
-- An object or expression with an integer type (other than int or unsigned int)
whose integer conversion rank is less than or equal to the rank of int and
-- A bit-field of type _Bool, int, signed int, or unsigned int.
If an int can represent all values of the original type (as restricted by the width, for a
bit-field), the value is converted to an int; otherwise, it is converted to an unsigned
- int. These are called the integer promotions.58) All other types are unchanged by the
+ int. These are called the integer promotions.<sup><a href="#note58"><b>58)</b></a></sup> All other types are unchanged by the
integer promotions.
3 The integer promotions preserve value including sign. As discussed earlier, whether a
''plain'' char is treated as signed is implementation-defined.
(<a href="#6.7.2.1">6.7.2.1</a>).
<a name="6.3.1.2" href="#6.3.1.2"><b> 6.3.1.2 Boolean type</b></a>
1 When any scalar value is converted to _Bool, the result is 0 if the value compares equal
- to 0; otherwise, the result is 1.59)
+ to 0; otherwise, the result is 1.<sup><a href="#note59"><b>59)</b></a></sup>
<a name="6.3.1.3" href="#6.3.1.3"><b> 6.3.1.3 Signed and unsigned integers</b></a>
1 When a value with integer type is converted to another integer type other than _Bool, if
the value can be represented by the new type, it is unchanged.
2 Otherwise, if the new type is unsigned, the value is converted by repeatedly adding or
subtracting one more than the maximum value that can be represented in the new type
- until the value is in the range of the new type.60)
+ until the value is in the range of the new type.<sup><a href="#note60"><b>60)</b></a></sup>
3 Otherwise, the new type is signed and the value cannot be represented in it; either the
result is implementation-defined or an implementation-defined signal is raised.
<a name="6.3.1.4" href="#6.3.1.4"><b> 6.3.1.4 Real floating and integer</b></a>
1 When a finite value of real floating type is converted to an integer type other than _Bool,
the fractional part is discarded (i.e., the value is truncated toward zero). If the value of
- the integral part cannot be represented by the integer type, the behavior is undefined.61)
+ the integral part cannot be represented by the integer type, the behavior is undefined.<sup><a href="#note61"><b>61)</b></a></sup>
- 58) The integer promotions are applied only: as part of the usual arithmetic conversions, to certain
+ <sup><a name="note58" href="#note58"><b>58)</b></a></sup> The integer promotions are applied only: as part of the usual arithmetic conversions, to certain
argument expressions, to the operands of the unary +, -, and ~ operators, and to both operands of the
shift operators, as specified by their respective subclauses.
- 59) NaNs do not compare equal to 0 and thus convert to 1.
- 60) The rules describe arithmetic on the mathematical value, not the value of a given type of expression.
- 61) The remaindering operation performed when a value of integer type is converted to unsigned type
+ <sup><a name="note59" href="#note59"><b>59)</b></a></sup> NaNs do not compare equal to 0 and thus convert to 1.
+ <sup><a name="note60" href="#note60"><b>60)</b></a></sup> The rules describe arithmetic on the mathematical value, not the value of a given type of expression.
+ <sup><a name="note61" href="#note61"><b>61)</b></a></sup> The remaindering operation performed when a value of integer type is converted to unsigned type
need not be performed when a value of real floating type is converted to unsigned type. Thus, the
range of portable real floating values is (-1, Utype_MAX+1).
-[<a name="
#p51" href="p51">page 51</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p51" href="#p51">page 51</a>] (<a href="#Contents">Contents</a>)
2 When a value of integer type is converted to a real floating type, if the value being
converted can be represented exactly in the new type, it is unchanged. If the value being
First, if the corresponding real type of either operand is long double, the other
operand is converted, without change of type domain, to a type whose
-[<a name="
#p52" href="p52">page 52</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p52" href="#p52">page 52</a>] (<a href="#Contents">Contents</a>)
corresponding real type is long double.
Otherwise, if the corresponding real type of either operand is double, the other
corresponding real type is double.
Otherwise, if the corresponding real type of either operand is float, the other
operand is converted, without change of type domain, to a type whose
- corresponding real type is float.62)
+ corresponding real type is float.<sup><a href="#note62"><b>62)</b></a></sup>
Otherwise, the integer promotions are performed on both operands. Then the
following rules are applied to the promoted operands:
If both operands have the same type, then no further conversion is needed.
corresponding to the type of the operand with signed integer type.
2 The values of floating operands and of the results of floating expressions may be
represented in greater precision and range than that required by the type; the types are not
- changed thereby.63)
+ changed thereby.<sup><a href="#note63"><b>63)</b></a></sup>
- 62) For example, addition of a double _Complex and a float entails just the conversion of the
+ <sup><a name="note62" href="#note62"><b>62)</b></a></sup> For example, addition of a double _Complex and a float entails just the conversion of the
float operand to double (and yields a double _Complex result).
- 63) The cast and assignment operators are still required to remove extra range and precision.
+ <sup><a name="note63" href="#note63"><b>63)</b></a></sup> The cast and assignment operators are still required to remove extra range and precision.
-[<a name="
#p53" href="p53">page 53</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p53" href="#p53">page 53</a>] (<a href="#Contents">Contents</a>)
<a name="6.3.2" href="#6.3.2"><b> 6.3.2 Other operands</b></a>
<a name="6.3.2.1" href="#6.3.2.1"><b> 6.3.2.1 Lvalues, arrays, and function designators</b></a>
1 An lvalue is an expression (with an object type other than void) that potentially
- designates an object;64) if an lvalue does not designate an object when it is evaluated, the
+ designates an object;<sup><a href="#note64"><b>64)</b></a></sup> if an lvalue does not designate an object when it is evaluated, the
behavior is undefined. When an object is said to have a particular type, the type is
specified by the lvalue used to designate the object. A modifiable lvalue is an lvalue that
does not have array type, does not have an incomplete type, does not have a const-
the array object and is not an lvalue. If the array object has register storage class, the
behavior is undefined.
4 A function designator is an expression that has function type. Except when it is the
- operand of the sizeof operator65) or the unary & operator, a function designator with
+ operand of the sizeof operator<sup><a href="#note65"><b>65)</b></a></sup> or the unary & operator, a function designator with
type ''function returning type'' is converted to an expression that has type ''pointer to
- 64) The name ''lvalue'' comes originally from the assignment expression E1 = E2, in which the left
+ <sup><a name="note64" href="#note64"><b>64)</b></a></sup> The name ''lvalue'' comes originally from the assignment expression E1 = E2, in which the left
operand E1 is required to be a (modifiable) lvalue. It is perhaps better considered as representing an
object ''locator value''. What is sometimes called ''rvalue'' is in this International Standard described
as the ''value of an expression''.
An obvious example of an lvalue is an identifier of an object. As a further example, if E is a unary
expression that is a pointer to an object, *E is an lvalue that designates the object to which E points.
- 65) Because this conversion does not occur, the operand of the sizeof operator remains a function
+ <sup><a name="note65" href="#note65"><b>65)</b></a></sup> Because this conversion does not occur, the operand of the sizeof operator remains a function
designator and violates the constraint in <a href="#6.5.3.4">6.5.3.4</a>.
-[<a name="
#p54" href="p54">page 54</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p54" href="#p54">page 54</a>] (<a href="#Contents">Contents</a>)
function returning type''.
Forward references: address and indirection operators (<a href="#6.5.3.2">6.5.3.2</a>), assignment operators
the q-qualified version of the type; the values stored in the original and converted pointers
shall compare equal.
3 An integer constant expression with the value 0, or such an expression cast to type
- void *, is called a null pointer constant.66) If a null pointer constant is converted to a
+ void *, is called a null pointer constant.<sup><a href="#note66"><b>66)</b></a></sup> If a null pointer constant is converted to a
pointer type, the resulting pointer, called a null pointer, is guaranteed to compare unequal
to a pointer to any object or function.
4 Conversion of a null pointer to another pointer type yields a null pointer of that type.
Any two null pointers shall compare equal.
5 An integer may be converted to any pointer type. Except as previously specified, the
result is implementation-defined, might not be correctly aligned, might not point to an
- entity of the referenced type, and might be a trap representation.67)
+ entity of the referenced type, and might be a trap representation.<sup><a href="#note67"><b>67)</b></a></sup>
6 Any pointer type may be converted to an integer type. Except as previously specified, the
result is implementation-defined. If the result cannot be represented in the integer type,
the behavior is undefined. The result need not be in the range of values of any integer
-
66) The macro NULL is defined in <a href="#7.19"><stddef.h></a> (and other headers) as a null pointer constant; see <a href="#7.19">7.19</a>.
- 67) The mapping functions for converting a pointer to an integer or an integer to a pointer are intended to
+
<sup><a name="note66" href="#note66"><b>66)</b></a></sup> The macro NULL is defined in <a href="#7.19"><stddef.h></a> (and other headers) as a null pointer constant; see <a href="#7.19">7.19</a>.
+ <sup><a name="note67" href="#note67"><b>67)</b></a></sup> The mapping functions for converting a pointer to an integer or an integer to a pointer are intended to
be consistent with the addressing structure of the execution environment.
-[<a name="
#p55" href="p55">page 55</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p55" href="#p55">page 55</a>] (<a href="#Contents">Contents</a>)
7 A pointer to an object type may be converted to a pointer to a different object type. If the
- resulting pointer is not correctly aligned68) for the referenced type, the behavior is
+ resulting pointer is not correctly aligned<sup><a href="#note68"><b>68)</b></a></sup> for the referenced type, the behavior is
undefined. Otherwise, when converted back again, the result shall compare equal to the
original pointer. When a pointer to an object is converted to a pointer to a character type,
the result points to the lowest addressed byte of the object. Successive increments of the
- 68) In general, the concept ''correctly aligned'' is transitive: if a pointer to type A is correctly aligned for a
+ <sup><a name="note68" href="#note68"><b>68)</b></a></sup> In general, the concept ''correctly aligned'' is transitive: if a pointer to type A is correctly aligned for a
pointer to type B, which in turn is correctly aligned for a pointer to type C, then a pointer to type A is
correctly aligned for a pointer to type C.
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+[<a name="
p56" href="#p56">page 56</a>] (<a href="#Contents">Contents</a>)
<a name="6.4" href="#6.4"><b> 6.4 Lexical elements</b></a>
- Syntax
+<b> Syntax</b>
1 token:
keyword
identifier
string-literal
punctuator
each non-white-space character that cannot be one of the above
- Constraints
+<b> Constraints</b>
2 Each preprocessing token that is converted to a token shall have the lexical form of a
keyword, an identifier, a constant, a string literal, or a punctuator.
- Semantics
+<b> Semantics</b>
3 A token is the minimal lexical element of the language in translation phases 7 and 8. The
categories of tokens are: keywords, identifiers, constants, string literals, and punctuators.
A preprocessing token is the minimal lexical element of the language in translation
phases 3 through 6. The categories of preprocessing tokens are: header names,
identifiers, preprocessing numbers, character constants, string literals, punctuators, and
single non-white-space characters that do not lexically match the other preprocessing
- token categories.69) If a ' or a " character matches the last category, the behavior is
+ token categories.<sup><a href="#note69"><b>69)</b></a></sup> If a ' or a " character matches the last category, the behavior is
undefined. Preprocessing tokens can be separated by white space; this consists of
comments (described later), or white-space characters (space, horizontal tab, new-line,
vertical tab, and form-feed), or both. As described in <a href="#6.10">6.10</a>, in certain circumstances
-
69) An additional category, placemarkers, is used internally in translation phase 4 (see <a href="#6.10.3.3">6.10.3.3</a>); it cannot
+
<sup><a name="note69" href="#note69"><b>69)</b></a></sup> An additional category, placemarkers, is used internally in translation phase 4 (see <a href="#6.10.3.3">6.10.3.3</a>); it cannot
occur in source files.
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+[<a name="
p57" href="#p57">page 57</a>] (<a href="#Contents">Contents</a>)
4 If the input stream has been parsed into preprocessing tokens up to a given character, the
next preprocessing token is the longest sequence of characters that could constitute a
(<a href="#6.5.3.1">6.5.3.1</a>), preprocessing directives (<a href="#6.10">6.10</a>), preprocessing numbers (<a href="#6.4.8">6.4.8</a>), string literals
(<a href="#6.4.5">6.4.5</a>).
<a name="6.4.1" href="#6.4.1"><b> 6.4.1 Keywords</b></a>
- Syntax
+<b> Syntax</b>
1 keyword: one of
alignof goto union
auto if unsigned
extern struct _Static_assert
float switch _Thread_local
for typedef
- Semantics
+<b> Semantics</b>
2 The above tokens (case sensitive) are reserved (in translation phases 7 and 8) for use as
keywords, and shall not be used otherwise. The keyword _Imaginary is reserved for
-[<a name="#p58" href="p58">page 58</a>] (<a href="#Contents">Contents</a>)
- specifying imaginary types.70)
+[<a name="p58" href="#p58">page 58</a>] (<a href="#Contents">Contents</a>)
+
+ specifying imaginary types.<sup><a href="#note70"><b>70)</b></a></sup>
<a name="6.4.2" href="#6.4.2"><b> 6.4.2 Identifiers</b></a>
<a name="6.4.2.1" href="#6.4.2.1"><b> 6.4.2.1 General</b></a>
- Syntax
+<b> Syntax</b>
1 identifier:
identifier-nondigit
identifier identifier-nondigit
N O P Q R S T U V W X Y Z
digit: one of
0 1 2 3 4 5 6 7 8 9
- Semantics
+<b> Semantics</b>
2 An identifier is a sequence of nondigit characters (including the underscore _, the
lowercase and uppercase Latin letters, and other characters) and digits, which designates
one or more entities as described in <a href="#6.2.1">6.2.1</a>. Lowercase and uppercase letters are distinct.
There is no specific limit on the maximum length of an identifier.
3 Each universal character name in an identifier shall designate a character whose encoding
- in ISO/IEC 10646 falls into one of the ranges specified in D.1.71) The initial character
+ in ISO/IEC 10646 falls into one of the ranges specified in D.1.<sup><a href="#note71"><b>71)</b></a></sup> The initial character
shall not be a universal character name designating a character whose encoding falls into
one of the ranges specified in <a href="#D.2">D.2</a>. An implementation may allow multibyte characters
that are not part of the basic source character set to appear in identifiers; which characters
-
70) One possible specification for imaginary types appears in <a href="#G">annex G</a>.
- 71) On systems in which linkers cannot accept extended characters, an encoding of the universal character
+
<sup><a name="note70" href="#note70"><b>70)</b></a></sup> One possible specification for imaginary types appears in <a href="#G">annex G</a>.
+ <sup><a name="note71" href="#note71"><b>71)</b></a></sup> On systems in which linkers cannot accept extended characters, an encoding of the universal character
name may be used in forming valid external identifiers. For example, some otherwise unused
character or sequence of characters may be used to encode the \u in a universal character name.
Extended characters may produce a long external identifier.
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+[<a name="
p59" href="#p59">page 59</a>] (<a href="#Contents">Contents</a>)
4 When preprocessing tokens are converted to tokens during translation phase 7, if a
preprocessing token could be converted to either a keyword or an identifier, it is converted
identifiers differ only in nonsignificant characters, the behavior is undefined.
Forward references: universal character names (<a href="#6.4.3">6.4.3</a>), macro replacement (<a href="#6.10.3">6.10.3</a>).
<a name="6.4.2.2" href="#6.4.2.2"><b> 6.4.2.2 Predefined identifiers</b></a>
- Semantics
+<b> Semantics</b>
1 The identifier __func__ shall be implicitly declared by the translator as if,
immediately following the opening brace of each function definition, the declaration
static const char __func__[] = "function-name";
- appeared, where function-name is the name of the lexically-enclosing function.72)
+ appeared, where function-name is the name of the lexically-enclosing function.<sup><a href="#note72"><b>72)</b></a></sup>
2 This name is encoded as if the implicit declaration had been written in the source
character set and then translated into the execution character set as indicated in translation
phase 5.
-
72) Since the name __func__ is reserved for any use by the implementation (<a href="#7.1.3">7.1.3</a>), if any other
+
<sup><a name="note72" href="#note72"><b>72)</b></a></sup> Since the name __func__ is reserved for any use by the implementation (<a href="#7.1.3">7.1.3</a>), if any other
identifier is explicitly declared using the name __func__, the behavior is undefined.
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+[<a name="
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<a name="6.4.3" href="#6.4.3"><b> 6.4.3 Universal character names</b></a>
- Syntax
+<b> Syntax</b>
1 universal-character-name:
\u hex-quad
\U hex-quad hex-quad
hex-quad:
hexadecimal-digit hexadecimal-digit
hexadecimal-digit hexadecimal-digit
- Constraints
+<b> Constraints</b>
2 A universal character name shall not specify a character whose short identifier is less than
00A0 other than 0024 ($), 0040 (@), or 0060 ('), nor one in the range D800 through
- DFFF inclusive.73)
- Description
+ DFFF inclusive.<sup><a href="#note73"><b>73)</b></a></sup>
+<b> Description</b>
3 Universal character names may be used in identifiers, character constants, and string
literals to designate characters that are not in the basic character set.
- Semantics
+<b> Semantics</b>
4 The universal character name \Unnnnnnnn designates the character whose eight-digit
- short identifier (as specified by ISO/IEC 10646) is nnnnnnnn.74) Similarly, the universal
+ short identifier (as specified by ISO/IEC 10646) is nnnnnnnn.<sup><a href="#note74"><b>74)</b></a></sup> Similarly, the universal
character name \unnnn designates the character whose four-digit short identifier is nnnn
(and whose eight-digit short identifier is 0000nnnn).
- 73) The disallowed characters are the characters in the basic character set and the code positions reserved
+ <sup><a name="note73" href="#note73"><b>73)</b></a></sup> The disallowed characters are the characters in the basic character set and the code positions reserved
by ISO/IEC 10646 for control characters, the character DELETE, and the S-zone (reserved for use by
UTF-16).
- 74) Short identifiers for characters were first specified in ISO/IEC 10646-1/AMD9:1997.
+ <sup><a name="note74" href="#note74"><b>74)</b></a></sup> Short identifiers for characters were first specified in ISO/IEC 10646-1/AMD9:1997.
-[<a name="
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+[<a name="
p61" href="#p61">page 61</a>] (<a href="#Contents">Contents</a>)
<a name="6.4.4" href="#6.4.4"><b> 6.4.4 Constants</b></a>
- Syntax
+<b> Syntax</b>
1 constant:
integer-constant
floating-constant
enumeration-constant
character-constant
- Constraints
+<b> Constraints</b>
2 Each constant shall have a type and the value of a constant shall be in the range of
representable values for its type.
- Semantics
+<b> Semantics</b>
3 Each constant has a type, determined by its form and value, as detailed later.
<a name="6.4.4.1" href="#6.4.4.1"><b> 6.4.4.1 Integer constants</b></a>
- Syntax
+<b> Syntax</b>
1 integer-constant:
decimal-constant integer-suffixopt
octal-constant integer-suffixopt
octal-digit: one of
0 1 2 3 4 5 6 7
-
-
-
-[<a name="#p62" href="p62">page 62</a>] (<a href="#Contents">Contents</a>)
+[<a name="p62" href="#p62">page 62</a>] (<a href="#Contents">Contents</a>)
hexadecimal-digit: one of
0 1 2 3 4 5 6 7 8 9
l L
long-long-suffix: one of
ll LL
- Description
+<b> Description</b>
2 An integer constant begins with a digit, but has no period or exponent part. It may have a
prefix that specifies its base and a suffix that specifies its type.
3 A decimal constant begins with a nonzero digit and consists of a sequence of decimal
digits 0 through 7 only. A hexadecimal constant consists of the prefix 0x or 0X followed
by a sequence of the decimal digits and the letters a (or A) through f (or F) with values
10 through 15 respectively.
- Semantics
+<b> Semantics</b>
4 The value of a decimal constant is computed base 10; that of an octal constant, base 8;
that of a hexadecimal constant, base 16. The lexically first digit is the most significant.
5 The type of an integer constant is the first of the corresponding list in which its value can
be represented.
-
-
-
-[<a name="#p63" href="p63">page 63</a>] (<a href="#Contents">Contents</a>)
+[<a name="p63" href="#p63">page 63</a>] (<a href="#Contents">Contents</a>)
Octal or Hexadecimal
Suffix Decimal Constant Constant
may be signed or unsigned. If an integer constant cannot be represented by any type in
its list and has no extended integer type, then the integer constant has no type.
-
-
-
-[<a name="#p64" href="p64">page 64</a>] (<a href="#Contents">Contents</a>)
+[<a name="p64" href="#p64">page 64</a>] (<a href="#Contents">Contents</a>)
<a name="6.4.4.2" href="#6.4.4.2"><b> 6.4.4.2 Floating constants</b></a>
- Syntax
+<b> Syntax</b>
1 floating-constant:
decimal-floating-constant
hexadecimal-floating-constant
floating-suffix: one of
f l F L
-[<a name="
#p65" href="p65">page 65</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p65" href="#p65">page 65</a>] (<a href="#Contents">Contents</a>)
- Description
+<b> Description</b>
2 A floating constant has a significand part that may be followed by an exponent part and a
suffix that specifies its type. The components of the significand part may include a digit
sequence representing the whole-number part, followed by a period (.), followed by a
e, E, p, or P followed by an exponent consisting of an optionally signed digit sequence.
Either the whole-number part or the fraction part has to be present; for decimal floating
constants, either the period or the exponent part has to be present.
- Semantics
+<b> Semantics</b>
3 The significand part is interpreted as a (decimal or hexadecimal) rational number; the
digit sequence in the exponent part is interpreted as a decimal integer. For decimal
floating constants, the exponent indicates the power of 10 by which the significand part is
type float. If suffixed by the letter l or L, it has type long double.
5 Floating constants are converted to internal format as if at translation-time. The
conversion of a floating constant shall not raise an exceptional condition or a floating-
- point exception at execution time. All floating constants of the same source form75) shall
+ point exception at execution time. All floating constants of the same source form<sup><a href="#note75"><b>75)</b></a></sup> shall
convert to the same internal format with the same value.
Recommended practice
6 The implementation should produce a diagnostic message if a hexadecimal constant
7 The translation-time conversion of floating constants should match the execution-time
conversion of character strings by library functions, such as strtod, given matching
inputs suitable for both conversions, the same result format, and default execution-time
- rounding.76)
+ rounding.<sup><a href="#note76"><b>76)</b></a></sup>
-
75) <a href="#1.23">1.23</a>, 1.230, 123e-2, 123e-02, and 1.23L are all different source forms and thus need not
+
<sup><a name="note75" href="#note75"><b>75)</b></a></sup> <a href="#1.23">1.23</a>, 1.230, 123e-2, 123e-02, and 1.23L are all different source forms and thus need not
convert to the same internal format and value.
- 76) The specification for the library functions recommends more accurate conversion than required for
+ <sup><a name="note76" href="#note76"><b>76)</b></a></sup> The specification for the library functions recommends more accurate conversion than required for
floating constants (see <a href="#7.22.1.3">7.22.1.3</a>).
-[<a name="
#p66" href="p66">page 66</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p66" href="#p66">page 66</a>] (<a href="#Contents">Contents</a>)
<a name="6.4.4.3" href="#6.4.4.3"><b> 6.4.4.3 Enumeration constants</b></a>
- Syntax
+<b> Syntax</b>
1 enumeration-constant:
identifier
- Semantics
+<b> Semantics</b>
2 An identifier declared as an enumeration constant has type int.
Forward references: enumeration specifiers (<a href="#6.7.2.2">6.7.2.2</a>).
<a name="6.4.4.4" href="#6.4.4.4"><b> 6.4.4.4 Character constants</b></a>
- Syntax
+<b> Syntax</b>
1 character-constant:
' c-char-sequence '
L' c-char-sequence '
\ octal-digit octal-digit
\ octal-digit octal-digit octal-digit
-
-
-
-[<a name="#p67" href="p67">page 67</a>] (<a href="#Contents">Contents</a>)
+[<a name="p67" href="#p67">page 67</a>] (<a href="#Contents">Contents</a>)
hexadecimal-escape-sequence:
\x hexadecimal-digit
hexadecimal-escape-sequence hexadecimal-digit
- Description
+<b> Description</b>
2 An integer character constant is a sequence of one or more multibyte characters enclosed
in single-quotes, as in 'x'. A wide character constant is the same, except prefixed by the
letter L, u, or U. With a few exceptions detailed later, the elements of the sequence are
8 In addition, characters not in the basic character set are representable by universal
character names and certain nongraphic characters are representable by escape sequences
consisting of the backslash \ followed by a lowercase letter: \a, \b, \f, \n, \r, \t,
- and \v.77)
-
+ and \v.<sup><a href="#note77"><b>77)</b></a></sup>
+[<a name="p68" href="#p68">page 68</a>] (<a href="#Contents">Contents</a>)
-[<a name="#p68" href="p68">page 68</a>] (<a href="#Contents">Contents</a>)
-
- Constraints
+<b> Constraints</b>
9 The value of an octal or hexadecimal escape sequence shall be in the range of
representable values for the corresponding type:
Prefix Corresponding Type
L the unsigned type corresponding to wchar_t
u char16_t
U char32_t
- Semantics
+<b> Semantics</b>
10 An integer character constant has type int. The value of an integer character constant
containing a single character that maps to a single-byte execution character is the
numerical value of the representation of the mapped character interpreted as an integer.
-
77) The semantics of these characters were discussed in <a href="#5.2.2">5.2.2</a>. If any other character follows a backslash,
+
<sup><a name="note77" href="#note77"><b>77)</b></a></sup> The semantics of these characters were discussed in <a href="#5.2.2">5.2.2</a>. If any other character follows a backslash,
the result is not a token and a diagnostic is required. See ''future language directions'' (<a href="#6.11.4">6.11.4</a>).
-[<a name="
#p69" href="p69">page 69</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p69" href="#p69">page 69</a>] (<a href="#Contents">Contents</a>)
14 EXAMPLE 3 Even if eight bits are used for objects that have type char, the construction '\x123'
specifies an integer character constant containing only one character, since a hexadecimal escape sequence
Forward references: common definitions <a href="#7.19"><stddef.h></a> (<a href="#7.19">7.19</a>), the mbtowc function
(<a href="#7.22.7.2">7.22.7.2</a>), Unicode utilities <a href="#7.27"><uchar.h></a> (<a href="#7.27">7.27</a>).
<a name="6.4.5" href="#6.4.5"><b> 6.4.5 String literals</b></a>
- Syntax
+<b> Syntax</b>
1 string-literal:
encoding-prefixopt " s-char-sequenceopt "
encoding-prefix:
any member of the source character set except
the double-quote ", backslash \, or new-line character
escape-sequence
- Constraints
+<b> Constraints</b>
2 A sequence of adjacent string literal tokens shall not include both a wide string literal and
a UTF-8 string literal.
- Description
+<b> Description</b>
3 A character string literal is a sequence of zero or more multibyte characters enclosed in
double-quotes, as in "xyz". A UTF-8 string literal is the same, except prefixed by u8.
A wide string literal is the same, except prefixed by the letter L, u, or U.
were in an integer character constant (for a character or UTF-8 string literal) or a wide
character constant (for a wide string literal), except that the single-quote ' is
representable either by itself or by the escape sequence \', but the double-quote " shall
-[<a name="#p70" href="p70">page 70</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p70" href="#p70">page 70</a>] (<a href="#Contents">Contents</a>)
be represented by the escape sequence \".
- Semantics
+<b> Semantics</b>
5 In translation phase 6, the multibyte character sequences specified by any sequence of
adjacent character and identically-prefixed string literal tokens are concatenated into a
single multibyte character sequence. If any of the tokens has an encoding prefix, the
tokens can be concatenated and, if so, the treatment of the resulting multibyte character
sequence are implementation-defined.
6 In translation phase 7, a byte or code of value zero is appended to each multibyte
- character sequence that results from a string literal or literals.78) The multibyte character
+ character sequence that results from a string literal or literals.<sup><a href="#note78"><b>78)</b></a></sup> The multibyte character
sequence is then used to initialize an array of static storage duration and length just
sufficient to contain the sequence. For character string literals, the array elements have
type char, and are initialized with the individual bytes of the multibyte character
-
78) A string literal need not be a string (see <a href="#7.1.1">7.1.1</a>), because a null character may be embedded in it by a
+
<sup><a name="note78" href="#note78"><b>78)</b></a></sup> A string literal need not be a string (see <a href="#7.1.1">7.1.1</a>), because a null character may be embedded in it by a
\0 escape sequence.
-[<a name="
#p71" href="p71">page 71</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p71" href="#p71">page 71</a>] (<a href="#Contents">Contents</a>)
"a" "b" L"c"
"a" L"b" "c"
Forward references: common definitions <a href="#7.19"><stddef.h></a> (<a href="#7.19">7.19</a>), the mbstowcs
function (<a href="#7.22.8.1">7.22.8.1</a>), Unicode utilities <a href="#7.27"><uchar.h></a> (<a href="#7.27">7.27</a>).
<a name="6.4.6" href="#6.4.6"><b> 6.4.6 Punctuators</b></a>
- Syntax
+<b> Syntax</b>
1 punctuator: one of
[ ] ( ) { } . ->
++ -- & * + - ~ !
= *= /= %= += -= <<= >>= &= ^= |=
, # ##
<: :> <% %> %: %:%:
- Semantics
+<b> Semantics</b>
2 A punctuator is a symbol that has independent syntactic and semantic significance.
Depending on context, it may specify an operation to be performed (which in turn may
yield a value or a function designator, produce a side effect, or some combination thereof)
in which case it is known as an operator (other forms of operator also exist in some
contexts). An operand is an entity on which an operator acts.
+[<a name="p72" href="#p72">page 72</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p72" href="p72">page 72</a>] (<a href="#Contents">Contents</a>)
-
-3 In all aspects of the language, the six tokens79)
+3 In all aspects of the language, the six tokens<sup><a href="#note79"><b>79)</b></a></sup>
<: :> <% %> %: %:%:
behave, respectively, the same as the six tokens
[ ] { } # ##
- except for their spelling.80)
+ except for their spelling.<sup><a href="#note80"><b>80)</b></a></sup>
Forward references: expressions (<a href="#6.5">6.5</a>), declarations (<a href="#6.7">6.7</a>), preprocessing directives
(<a href="#6.10">6.10</a>), statements (<a href="#6.8">6.8</a>).
<a name="6.4.7" href="#6.4.7"><b> 6.4.7 Header names</b></a>
- Syntax
+<b> Syntax</b>
1 header-name:
< h-char-sequence >
" q-char-sequence "
q-char:
any member of the source character set except
the new-line character and "
- Semantics
+<b> Semantics</b>
2 The sequences in both forms of header names are mapped in an implementation-defined
manner to headers or external source file names as specified in <a href="#6.10.2">6.10.2</a>.
3 If the characters ', \, ", //, or /* occur in the sequence between the < and > delimiters,
- 79) These tokens are sometimes called ''digraphs''.
-
80) Thus [ and <: behave differently when ''stringized'' (see <a href="#6.10.3.2">6.10.3.2</a>), but can otherwise be freely
+ <sup><a name="note79" href="#note79"><b>79)</b></a></sup> These tokens are sometimes called ''digraphs''.
+
<sup><a name="note80" href="#note80"><b>80)</b></a></sup> Thus [ and <: behave differently when ''stringized'' (see <a href="#6.10.3.2">6.10.3.2</a>), but can otherwise be freely
interchanged.
-[<a name="
#p73" href="p73">page 73</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p73" href="#p73">page 73</a>] (<a href="#Contents">Contents</a>)
- sequence between the " delimiters, the behavior is undefined.81) Header name
+ sequence between the " delimiters, the behavior is undefined.<sup><a href="#note81"><b>81)</b></a></sup> Header name
preprocessing tokens are recognized only within #include preprocessing directives and
- in implementation-defined locations within #pragma directives.82)
+ in implementation-defined locations within #pragma directives.<sup><a href="#note82"><b>82)</b></a></sup>
4 EXAMPLE The following sequence of characters:
0x3<1/a.h>1e2
#include <1/a.h>
Forward references: source file inclusion (<a href="#6.10.2">6.10.2</a>).
<a name="6.4.8" href="#6.4.8"><b> 6.4.8 Preprocessing numbers</b></a>
- Syntax
+<b> Syntax</b>
1 pp-number:
digit
. digit
pp-number p sign
pp-number P sign
pp-number .
- Description
+<b> Description</b>
2 A preprocessing number begins with a digit optionally preceded by a period (.) and may
be followed by valid identifier characters and the character sequences e+, e-, E+, E-,
p+, p-, P+, or P-.
3 Preprocessing number tokens lexically include all floating and integer constant tokens.
- Semantics
+<b> Semantics</b>
4 A preprocessing number does not have type or a value; it acquires both after a successful
conversion (as part of translation phase 7) to a floating constant token or an integer
constant token.
- 81) Thus, sequences of characters that resemble escape sequences cause undefined behavior.
-
82) For an example of a header name preprocessing token used in a #pragma directive, see <a href="#6.10.9">6.10.9</a>.
+ <sup><a name="note81" href="#note81"><b>81)</b></a></sup> Thus, sequences of characters that resemble escape sequences cause undefined behavior.
+
<sup><a name="note82" href="#note82"><b>82)</b></a></sup> For an example of a header name preprocessing token used in a #pragma directive, see <a href="#6.10.9">6.10.9</a>.
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<a name="6.4.9" href="#6.4.9"><b> 6.4.9 Comments</b></a>
1 Except within a character constant, a string literal, or a comment, the characters /*
introduce a comment. The contents of such a comment are examined only to identify
- multibyte characters and to find the characters */ that terminate it.83)
+ multibyte characters and to find the characters */ that terminate it.<sup><a href="#note83"><b>83)</b></a></sup>
2 Except within a character constant, a string literal, or a comment, the characters //
introduce a comment that includes all multibyte characters up to, but not including, the
next new-line character. The contents of such a comment are examined only to identify
- 83) Thus, /* ... */ comments do not nest.
+ <sup><a name="note83" href="#note83"><b>83)</b></a></sup> Thus, /* ... */ comments do not nest.
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<a name="6.5" href="#6.5"><b> 6.5 Expressions</b></a>
1 An expression is a sequence of operators and operands that specifies computation of a
on the same scalar object or a value computation using the value of the same scalar
object, the behavior is undefined. If there are multiple allowable orderings of the
subexpressions of an expression, the behavior is undefined if such an unsequenced side
- effect occurs in any of the orderings.84)
-3 The grouping of operators and operands is indicated by the syntax.85) Except as specified
- later, side effects and value computations of subexpressions are unsequenced.86) *
+ effect occurs in any of the orderings.<sup><a href="#note84"><b>84)</b></a></sup>
+3 The grouping of operators and operands is indicated by the syntax.<sup><a href="#note85"><b>85)</b></a></sup> Except as specified
+ later, side effects and value computations of subexpressions are unsequenced.<sup><a href="#note86"><b>86)</b></a></sup> *
4 Some operators (the unary operator ~, and the binary operators <<, >>, &, ^, and |,
collectively described as bitwise operators) are required to have operands that have
integer type. These operators yield values that depend on the internal representations of
- 84) This paragraph renders undefined statement expressions such as
+ <sup><a name="note84" href="#note84"><b>84)</b></a></sup> This paragraph renders undefined statement expressions such as
i = ++i + 1;
a[i++] = i;
while allowing
i = i + 1;
a[i] = i;
- 85) The syntax specifies the precedence of operators in the evaluation of an expression, which is the same
+ <sup><a name="note85" href="#note85"><b>85)</b></a></sup> The syntax specifies the precedence of operators in the evaluation of an expression, which is the same
as the order of the major subclauses of this subclause, highest precedence first. Thus, for example, the
expressions allowed as the operands of the binary + operator (<a href="#6.5.6">6.5.6</a>) are those expressions defined in
<a href="#6.5.1">6.5.1</a> through <a href="#6.5.6">6.5.6</a>. The exceptions are cast expressions (<a href="#6.5.4">6.5.4</a>) as operands of unary operators
the conditional operator ? : (<a href="#6.5.15">6.5.15</a>).
Within each major subclause, the operators have the same precedence. Left- or right-associativity is
indicated in each subclause by the syntax for the expressions discussed therein.
- 86) In an expression that is evaluated more than once during the execution of a program, unsequenced and
+ <sup><a name="note86" href="#note86"><b>86)</b></a></sup> In an expression that is evaluated more than once during the execution of a program, unsequenced and
indeterminately sequenced evaluations of its subexpressions need not be performed consistently in
different evaluations.
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6 The effective type of an object for an access to its stored value is the declared type of the
- object, if any.87) If a value is stored into an object having no declared type through an
+ object, if any.<sup><a href="#note87"><b>87)</b></a></sup> If a value is stored into an object having no declared type through an
lvalue having a type that is not a character type, then the type of the lvalue becomes the
effective type of the object for that access and for subsequent accesses that do not modify
the stored value. If a value is copied into an object having no declared type using
all other accesses to an object having no declared type, the effective type of the object is
simply the type of the lvalue used for the access.
7 An object shall have its stored value accessed only by an lvalue expression that has one of
- the following types:88)
+ the following types:<sup><a href="#note88"><b>88)</b></a></sup>
-- a type compatible with the effective type of the object,
-- a qualified version of a type compatible with the effective type of the object,
-- a type that is the signed or unsigned type corresponding to the effective type of the
-- a character type.
8 A floating expression may be contracted, that is, evaluated as though it were a single
operation, thereby omitting rounding errors implied by the source code and the
- expression evaluation method.
89) The FP_CONTRACT pragma in <a href="#7.12"><math.h></a> provides a
+ expression evaluation method.
<sup><a href="#note89"><b>89)</b></a></sup> The FP_CONTRACT pragma in <a href="#7.12"><math.h></a> provides a
way to disallow contracted expressions. Otherwise, whether and how expressions are
- contracted is implementation-defined.90)
+ contracted is implementation-defined.<sup><a href="#note90"><b>90)</b></a></sup>
Forward references: the FP_CONTRACT pragma (<a href="#7.12.2">7.12.2</a>), copying functions (<a href="#7.23.2">7.23.2</a>).
- 87) Allocated objects have no declared type.
- 88) The intent of this list is to specify those circumstances in which an object may or may not be aliased.
- 89) The intermediate operations in the contracted expression are evaluated as if to infinite precision and
+ <sup><a name="note87" href="#note87"><b>87)</b></a></sup> Allocated objects have no declared type.
+ <sup><a name="note88" href="#note88"><b>88)</b></a></sup> The intent of this list is to specify those circumstances in which an object may or may not be aliased.
+ <sup><a name="note89" href="#note89"><b>89)</b></a></sup> The intermediate operations in the contracted expression are evaluated as if to infinite precision and
range, while the final operation is rounded to the format determined by the expression evaluation
method. A contracted expression might also omit the raising of floating-point exceptions.
- 90) This license is specifically intended to allow implementations to exploit fast machine instructions that
+ <sup><a name="note90" href="#note90"><b>90)</b></a></sup> This license is specifically intended to allow implementations to exploit fast machine instructions that
combine multiple C operators. As contractions potentially undermine predictability, and can even
decrease accuracy for containing expressions, their use needs to be well-defined and clearly
documented.
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<a name="6.5.1" href="#6.5.1"><b> 6.5.1 Primary expressions</b></a>
- Syntax
+<b> Syntax</b>
1 primary-expression:
identifier
constant
string-literal
( expression )
generic-selection
- Semantics
+<b> Semantics</b>
2 An identifier is a primary expression, provided it has been declared as designating an
object (in which case it is an lvalue) or a function (in which case it is a function
- designator).91)
+ designator).<sup><a href="#note91"><b>91)</b></a></sup>
3 A constant is a primary expression. Its type depends on its form and value, as detailed in
-<a name="6.4.4" href="#6.4.4"><b> 6.4.4.</b></a>
+ <a href="#6.4.4">6.4.4</a>.
4 A string literal is a primary expression. It is an lvalue with type as detailed in <a href="#6.4.5">6.4.5</a>.
5 A parenthesized expression is a primary expression. Its type and value are identical to
those of the unparenthesized expression. It is an lvalue, a function designator, or a void
designator, or a void expression.
Forward references: declarations (<a href="#6.7">6.7</a>).
<a name="6.5.1.1" href="#6.5.1.1"><b> 6.5.1.1 Generic selection</b></a>
- Syntax
+<b> Syntax</b>
1 generic-selection:
_Generic ( assignment-expression , generic-assoc-list )
generic-assoc-list:
generic-association:
type-name : assignment-expression
default : assignment-expression
- Constraints
+<b> Constraints</b>
2 A generic selection shall have no more than one default generic association. The type
name in a generic association shall specify a complete object type other than a variably
- 91) Thus, an undeclared identifier is a violation of the syntax.
+ <sup><a name="note91" href="#note91"><b>91)</b></a></sup> Thus, an undeclared identifier is a violation of the syntax.
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modified type. No two generic associations in the same generic selection shall specify
compatible types. The controlling expression of a generic selection shall have type
compatible with at most one of the types named in its generic association list. If a
generic selection has no default generic association, its controlling expression shall
have type compatible with exactly one of the types named in its generic association list.
- Semantics
+<b> Semantics</b>
3 The controlling expression of a generic selection is not evaluated. If a generic selection
has a generic association with a type name that is compatible with the type of the
controlling expression, then the result expression of the generic selection is the
)(X)
<a name="6.5.2" href="#6.5.2"><b> 6.5.2 Postfix operators</b></a>
- Syntax
+<b> Syntax</b>
1 postfix-expression:
primary-expression
postfix-expression [ expression ]
assignment-expression
argument-expression-list , assignment-expression
-
-
-
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<a name="6.5.2.1" href="#6.5.2.1"><b> 6.5.2.1 Array subscripting</b></a>
- Constraints
+<b> Constraints</b>
1 One of the expressions shall have type ''pointer to complete object type'', the other
expression shall have integer type, and the result has type ''type''.
- Semantics
+<b> Semantics</b>
2 A postfix expression followed by an expression in square brackets [] is a subscripted
designation of an element of an array object. The definition of the subscript operator []
is that E1[E2] is identical to (*((E1)+(E2))). Because of the conversion rules that
Forward references: additive operators (<a href="#6.5.6">6.5.6</a>), address and indirection operators
(<a href="#6.5.3.2">6.5.3.2</a>), array declarators (<a href="#6.7.6.2">6.7.6.2</a>).
<a name="6.5.2.2" href="#6.5.2.2"><b> 6.5.2.2 Function calls</b></a>
- Constraints
-1 The expression that denotes the called function92) shall have type pointer to function
+<b> Constraints</b>
+1 The expression that denotes the called function<sup><a href="#note92"><b>92)</b></a></sup> shall have type pointer to function
returning void or returning a complete object type other than an array type.
2 If the expression that denotes the called function has a type that includes a prototype, the
number of arguments shall agree with the number of parameters. Each argument shall
- 92) Most often, this is the result of converting an identifier that is a function designator.
+ <sup><a name="note92" href="#note92"><b>92)</b></a></sup> Most often, this is the result of converting an identifier that is a function designator.
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have a type such that its value may be assigned to an object with the unqualified version
of the type of its corresponding parameter.
- Semantics
+<b> Semantics</b>
3 A postfix expression followed by parentheses () containing a possibly empty, comma-
separated list of expressions is a function call. The postfix expression denotes the called
function. The list of expressions specifies the arguments to the function.
4 An argument may be an expression of any complete object type. In preparing for the call
to a function, the arguments are evaluated, and each parameter is assigned the value of the
- corresponding argument.93)
+ corresponding argument.<sup><a href="#note93"><b>93)</b></a></sup>
5 If the expression that denotes the called function has type pointer to function returning an
object type, the function call expression has the same type as that object type, and has the
value determined as specified in <a href="#6.8.6.4">6.8.6.4</a>. Otherwise, the function call has type void. *
- 93) A function may change the values of its parameters, but these changes cannot affect the values of the
+ <sup><a name="note93" href="#note93"><b>93)</b></a></sup> A function may change the values of its parameters, but these changes cannot affect the values of the
arguments. On the other hand, it is possible to pass a pointer to an object, and the function may
change the value of the object pointed to. A parameter declared to have array or function type is
adjusted to have a pointer type as described in <a href="#6.9.1">6.9.1</a>.
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8 No other conversions are performed implicitly; in particular, the number and types of
arguments are not compared with those of the parameters in a function definition that
arguments but before the actual call. Every evaluation in the calling function (including
other function calls) that is not otherwise specifically sequenced before or after the
execution of the body of the called function is indeterminately sequenced with respect to
- the execution of the called function.94)
+ the execution of the called function.<sup><a href="#note94"><b>94)</b></a></sup>
11 Recursive function calls shall be permitted, both directly and indirectly through any chain
of other functions.
12 EXAMPLE In the function call
Forward references: function declarators (including prototypes) (<a href="#6.7.6.3">6.7.6.3</a>), function
definitions (<a href="#6.9.1">6.9.1</a>), the return statement (<a href="#6.8.6.4">6.8.6.4</a>), simple assignment (<a href="#6.5.16.1">6.5.16.1</a>).
<a name="6.5.2.3" href="#6.5.2.3"><b> 6.5.2.3 Structure and union members</b></a>
- Constraints
+<b> Constraints</b>
1 The first operand of the . operator shall have an atomic, qualified, or unqualified
structure or union type, and the second operand shall name a member of that type.
2 The first operand of the -> operator shall have type ''pointer to atomic, qualified, or
unqualified structure'' or ''pointer to atomic, qualified, or unqualified union'', and the
second operand shall name a member of the type pointed to.
- Semantics
+<b> Semantics</b>
3 A postfix expression followed by the . operator and an identifier designates a member of
- a structure or union object. The value is that of the named member,95) and is an lvalue if
+ a structure or union object. The value is that of the named member,<sup><a href="#note95"><b>95)</b></a></sup> and is an lvalue if
the first expression is an lvalue. If the first expression has qualified type, the result has
the so-qualified version of the type of the designated member.
- 94) In other words, function executions do not ''interleave'' with each other.
- 95) If the member used to read the contents of a union object is not the same as the member last used to
+ <sup><a name="note94" href="#note94"><b>94)</b></a></sup> In other words, function executions do not ''interleave'' with each other.
+ <sup><a name="note95" href="#note95"><b>95)</b></a></sup> If the member used to read the contents of a union object is not the same as the member last used to
store a value in the object, the appropriate part of the object representation of the value is reinterpreted
as an object representation in the new type as described in <a href="#6.2.6">6.2.6</a> (a process sometimes called ''type
punning''). This might be a trap representation.
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4 A postfix expression followed by the -> operator and an identifier designates a member
of a structure or union object. The value is that of the named member of the object to
- which the first expression points, and is an lvalue.96) If the first expression is a pointer to
+ which the first expression points, and is an lvalue.<sup><a href="#note96"><b>96)</b></a></sup> If the first expression is a pointer to
a qualified type, the result has the so-qualified version of the type of the designated
member.
5 Accessing a member of an atomic structure or union object results in undefined
- behavior.97)
+ behavior.<sup><a href="#note97"><b>97)</b></a></sup>
6 One special guarantee is made in order to simplify the use of unions: if a union contains
several structures that share a common initial sequence (see below), and if the union
object currently contains one of these structures, it is permitted to inspect the common
- 96) If &E is a valid pointer expression (where & is the ''address-of '' operator, which generates a pointer to
+ <sup><a name="note96" href="#note96"><b>96)</b></a></sup> If &E is a valid pointer expression (where & is the ''address-of '' operator, which generates a pointer to
its operand), the expression (&E)->MOS is the same as E.MOS.
- 97) For example, a data race would occur if access to the entire structure or union in one thread conflicts
+ <sup><a name="note97" href="#note97"><b>97)</b></a></sup> For example, a data race would occur if access to the entire structure or union in one thread conflicts
with access to a member from another thread, where at least one access is a modification. Members
can be safely accessed using a non-atomic object which is assigned to or from the atomic object.
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9 EXAMPLE 3 The following is a valid fragment:
union {
Forward references: address and indirection operators (<a href="#6.5.3.2">6.5.3.2</a>), structure and union
specifiers (<a href="#6.7.2.1">6.7.2.1</a>).
-
-
-
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+[<a name="p84" href="#p84">page 84</a>] (<a href="#Contents">Contents</a>)
<a name="6.5.2.4" href="#6.5.2.4"><b> 6.5.2.4 Postfix increment and decrement operators</b></a>
- Constraints
+<b> Constraints</b>
1 The operand of the postfix increment or decrement operator shall have atomic, qualified,
or unqualified real or pointer type, and shall be a modifiable lvalue.
- Semantics
+<b> Semantics</b>
2 The result of the postfix ++ operator is the value of the operand. As a side effect, the
value of the operand object is incremented (that is, the value 1 of the appropriate type is
added to it). See the discussions of additive operators and compound assignment for
updating the stored value of the operand. With respect to an indeterminately-sequenced
function call, the operation of postfix ++ is a single evaluation. Postfix ++ on an object
with atomic type is a read-modify-write operation with memory_order_seq_cst
- memory order semantics.98)
+ memory order semantics.<sup><a href="#note98"><b>98)</b></a></sup>
3 The postfix -- operator is analogous to the postfix ++ operator, except that the value of
the operand is decremented (that is, the value 1 of the appropriate type is subtracted from
it).
Forward references: additive operators (<a href="#6.5.6">6.5.6</a>), compound assignment (<a href="#6.5.16.2">6.5.16.2</a>).
<a name="6.5.2.5" href="#6.5.2.5"><b> 6.5.2.5 Compound literals</b></a>
- Constraints
+<b> Constraints</b>
1 The type name shall specify a complete object type or an array of unknown size, but not a
variable length array type.
2 All the constraints for initializer lists in <a href="#6.7.9">6.7.9</a> also apply to compound literals.
- Semantics
+<b> Semantics</b>
3 A postfix expression that consists of a parenthesized type name followed by a brace-
enclosed list of initializers is a compound literal. It provides an unnamed object whose
- value is given by the initializer list.99)
+ value is given by the initializer list.<sup><a href="#note99"><b>99)</b></a></sup>
- 98) Where a pointer to an atomic object can be formed, this is equivalent to the following code sequence
+ <sup><a name="note98" href="#note98"><b>98)</b></a></sup> Where a pointer to an atomic object can be formed, this is equivalent to the following code sequence
where T is the type of E:
T tmp;
T result = E;
} while (!atomic_compare_exchange_strong(&E, &result, tmp));
with result being the result of the operation.
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4 If the type name specifies an array of unknown size, the size is determined by the
initializer list as specified in <a href="#6.7.9">6.7.9</a>, and the type of the compound literal is that of the
initializer list. If the compound literal occurs outside the body of a function, the object
has static storage duration; otherwise, it has automatic storage duration associated with
the enclosing block.
-6 All the semantic rules for initializer lists in <a href="#6.7.9">6.7.9</a> also apply to compound literals.100)
+6 All the semantic rules for initializer lists in <a href="#6.7.9">6.7.9</a> also apply to compound literals.<sup><a href="#note100"><b>100)</b></a></sup>
7 String literals, and compound literals with const-qualified types, need not designate
- distinct objects.101)
+ distinct objects.<sup><a href="#note101"><b>101)</b></a></sup>
8 EXAMPLE 1 The file scope definition
int *p = (int []){2, 4};
initializes p to point to the first element of an array of two ints, the first having the value two and the
- 99) Note that this differs from a cast expression. For example, a cast specifies a conversion to scalar types
+ <sup><a name="note99" href="#note99"><b>99)</b></a></sup> Note that this differs from a cast expression. For example, a cast specifies a conversion to scalar types
or void only, and the result of a cast expression is not an lvalue.
- 100) For example, subobjects without explicit initializers are initialized to zero.
- 101) This allows implementations to share storage for string literals and constant compound literals with
+ <sup><a name="note100" href="#note100"><b>100)</b></a></sup> For example, subobjects without explicit initializers are initialized to zero.
+ <sup><a name="note101" href="#note101"><b>101)</b></a></sup> This allows implementations to share storage for string literals and constant compound literals with
the same or overlapping representations.
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drawline(&(struct point){.x=1, .y=1},
&(struct point){.x=3, .y=4});
Forward references: type names (<a href="#6.7.7">6.7.7</a>), initialization (<a href="#6.7.9">6.7.9</a>).
-
-
-
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<a name="6.5.3" href="#6.5.3"><b> 6.5.3 Unary operators</b></a>
- Syntax
+<b> Syntax</b>
1 unary-expression:
postfix-expression
++ unary-expression
unary-operator: one of
& * + - ~ !
<a name="6.5.3.1" href="#6.5.3.1"><b> 6.5.3.1 Prefix increment and decrement operators</b></a>
- Constraints
+<b> Constraints</b>
1 The operand of the prefix increment or decrement operator shall have atomic, qualified,
or unqualified real or pointer type, and shall be a modifiable lvalue.
- Semantics
+<b> Semantics</b>
2 The value of the operand of the prefix ++ operator is incremented. The result is the new
value of the operand after incrementation. The expression ++E is equivalent to (E+=1).
See the discussions of additive operators and compound assignment for information on
operand is decremented.
Forward references: additive operators (<a href="#6.5.6">6.5.6</a>), compound assignment (<a href="#6.5.16.2">6.5.16.2</a>).
<a name="6.5.3.2" href="#6.5.3.2"><b> 6.5.3.2 Address and indirection operators</b></a>
- Constraints
+<b> Constraints</b>
1 The operand of the unary & operator shall be either a function designator, the result of a
[] or unary * operator, or an lvalue that designates an object that is not a bit-field and is
not declared with the register storage-class specifier.
2 The operand of the unary * operator shall have pointer type.
- Semantics
+<b> Semantics</b>
3 The unary & operator yields the address of its operand. If the operand has type ''type'',
the result has type ''pointer to type''. If the operand is the result of a unary * operator,
neither that operator nor the & operator is evaluated and the result is as if both were
omitted, except that the constraints on the operators still apply and the result is not an
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lvalue. Similarly, if the operand is the result of a [] operator, neither the & operator nor
the unary * that is implied by the [] is evaluated and the result is as if the & operator
a function designator; if it points to an object, the result is an lvalue designating the
object. If the operand has type ''pointer to type'', the result has type ''type''. If an
invalid value has been assigned to the pointer, the behavior of the unary * operator is
- undefined.102)
+ undefined.<sup><a href="#note102"><b>102)</b></a></sup>
Forward references: storage-class specifiers (<a href="#6.7.1">6.7.1</a>), structure and union specifiers
(<a href="#6.7.2.1">6.7.2.1</a>).
<a name="6.5.3.3" href="#6.5.3.3"><b> 6.5.3.3 Unary arithmetic operators</b></a>
- Constraints
+<b> Constraints</b>
1 The operand of the unary + or - operator shall have arithmetic type; of the ~ operator,
integer type; of the ! operator, scalar type.
- Semantics
+<b> Semantics</b>
2 The result of the unary + operator is the value of its (promoted) operand. The integer
promotions are performed on the operand, and the result has the promoted type.
3 The result of the unary - operator is the negative of its (promoted) operand. The integer
- 102) Thus, &*E is equivalent to E (even if E is a null pointer), and &(E1[E2]) to ((E1)+(E2)). It is
+ <sup><a name="note102" href="#note102"><b>102)</b></a></sup> Thus, &*E is equivalent to E (even if E is a null pointer), and &(E1[E2]) to ((E1)+(E2)). It is
always true that if E is a function designator or an lvalue that is a valid operand of the unary &
operator, *&E is a function designator or an lvalue equal to E. If *P is an lvalue and T is the name of
an object pointer type, *(T)P is an lvalue that has a type compatible with that to which T points.
address inappropriately aligned for the type of object pointed to, and the address of an object after the
end of its lifetime.
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<a name="6.5.3.4" href="#6.5.3.4"><b> 6.5.3.4 The sizeof and alignof operators</b></a>
- Constraints
+<b> Constraints</b>
1 The sizeof operator shall not be applied to an expression that has function type or an
incomplete type, to the parenthesized name of such a type, or to an expression that
designates a bit-field member. The alignof operator shall not be applied to a function
type or an incomplete type.
- Semantics
+<b> Semantics</b>
2 The sizeof operator yields the size (in bytes) of its operand, which may be an
expression or the parenthesized name of a type. The size is determined from the type of
the operand. The result is an integer. If the type of the operand is a variable length array
requirement of the element type.
4 When sizeof is applied to an operand that has type char, unsigned char, or
signed char, (or a qualified version thereof) the result is 1. When applied to an
- operand that has array type, the result is the total number of bytes in the array.103) When
+ operand that has array type, the result is the total number of bytes in the array.<sup><a href="#note103"><b>103)</b></a></sup> When
applied to an operand that has structure or union type, the result is the total number of
bytes in such an object, including internal and trailing padding.
5 The value of the result of both operators is implementation-defined, and its type (an
- 103) When applied to a parameter declared to have array or function type, the sizeof operator yields the
+ <sup><a name="note103" href="#note103"><b>103)</b></a></sup> When applied to a parameter declared to have array or function type, the sizeof operator yields the
size of the adjusted (pointer) type (see <a href="#6.9.1">6.9.1</a>).
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size_t fsize3(int n)
{
Forward references: common definitions <a href="#7.19"><stddef.h></a> (<a href="#7.19">7.19</a>), declarations (<a href="#6.7">6.7</a>),
structure and union specifiers (<a href="#6.7.2.1">6.7.2.1</a>), type names (<a href="#6.7.7">6.7.7</a>), array declarators (<a href="#6.7.6.2">6.7.6.2</a>).
<a name="6.5.4" href="#6.5.4"><b> 6.5.4 Cast operators</b></a>
- Syntax
+<b> Syntax</b>
1 cast-expression:
unary-expression
( type-name ) cast-expression
- Constraints
+<b> Constraints</b>
2 Unless the type name specifies a void type, the type name shall specify atomic, qualified,
or unqualified scalar type, and the operand shall have scalar type.
3 Conversions that involve pointers, other than where permitted by the constraints of
<a href="#6.5.16.1">6.5.16.1</a>, shall be specified by means of an explicit cast.
4 A pointer type shall not be converted to any floating type. A floating type shall not be
converted to any pointer type.
- Semantics
+<b> Semantics</b>
5 Preceding an expression by a parenthesized type name converts the value of the
- expression to the named type. This construction is called a cast.104) A cast that specifies
+ expression to the named type. This construction is called a cast.<sup><a href="#note104"><b>104)</b></a></sup> A cast that specifies
no conversion has no effect on the type or value of an expression.
6 If the value of the expression is represented with greater precision or range than required
by the type named by the cast (<a href="#6.3.1.8">6.3.1.8</a>), then the cast specifies a conversion even if the
Forward references: equality operators (<a href="#6.5.9">6.5.9</a>), function declarators (including
prototypes) (<a href="#6.7.6.3">6.7.6.3</a>), simple assignment (<a href="#6.5.16.1">6.5.16.1</a>), type names (<a href="#6.7.7">6.7.7</a>).
- 104) A cast does not yield an lvalue. Thus, a cast to a qualified type has the same effect as a cast to the
+ <sup><a name="note104" href="#note104"><b>104)</b></a></sup> A cast does not yield an lvalue. Thus, a cast to a qualified type has the same effect as a cast to the
unqualified version of the type.
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<a name="6.5.5" href="#6.5.5"><b> 6.5.5 Multiplicative operators</b></a>
- Syntax
+<b> Syntax</b>
1 multiplicative-expression:
cast-expression
multiplicative-expression * cast-expression
multiplicative-expression / cast-expression
multiplicative-expression % cast-expression
- Constraints
+<b> Constraints</b>
2 Each of the operands shall have arithmetic type. The operands of the % operator shall
have integer type.
- Semantics
+<b> Semantics</b>
3 The usual arithmetic conversions are performed on the operands.
4 The result of the binary * operator is the product of the operands.
5 The result of the / operator is the quotient from the division of the first operand by the
second; the result of the % operator is the remainder. In both operations, if the value of
the second operand is zero, the behavior is undefined.
6 When integers are divided, the result of the / operator is the algebraic quotient with any
- fractional part discarded.105) If the quotient a/b is representable, the expression
+ fractional part discarded.<sup><a href="#note105"><b>105)</b></a></sup> If the quotient a/b is representable, the expression
(a/b)*b + a%b shall equal a; otherwise, the behavior of both a/b and a%b is
undefined.
<a name="6.5.6" href="#6.5.6"><b> 6.5.6 Additive operators</b></a>
- Syntax
+<b> Syntax</b>
1 additive-expression:
multiplicative-expression
additive-expression + multiplicative-expression
additive-expression - multiplicative-expression
- Constraints
+<b> Constraints</b>
2 For addition, either both operands shall have arithmetic type, or one operand shall be a
pointer to a complete object type and the other shall have integer type. (Incrementing is
equivalent to adding 1.)
- 105) This is often called ''truncation toward zero''.
+ <sup><a name="note105" href="#note105"><b>105)</b></a></sup> This is often called ''truncation toward zero''.
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-- both operands have arithmetic type;
-- both operands are pointers to qualified or unqualified versions of compatible complete
-- the left operand is a pointer to a complete object type and the right operand has
integer type.
(Decrementing is equivalent to subtracting 1.)
- Semantics
+<b> Semantics</b>
4 If both operands have arithmetic type, the usual arithmetic conversions are performed on
them.
5 The result of the binary + operator is the sum of the operands.
other words, if the expressions P and Q point to, respectively, the i-th and j-th elements of
an array object, the expression (P)-(Q) has the value i-j provided the value fits in an
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object of type ptrdiff_t. Moreover, if the expression P points either to an element of
an array object or one past the last element of an array object, and the expression Q points
to the last element of the same array object, the expression ((Q)+1)-(P) has the same
value as ((Q)-(P))+1 and as -((P)-((Q)+1)), and has the value zero if the
expression P points one past the last element of the array object, even though the
- expression (Q)+1 does not point to an element of the array object.106)
+ expression (Q)+1 does not point to an element of the array object.<sup><a href="#note106"><b>106)</b></a></sup>
10 EXAMPLE Pointer arithmetic is well defined with pointers to variable length array types.
{
int n = 4, m = 3;
Forward references: array declarators (<a href="#6.7.6.2">6.7.6.2</a>), common definitions <a href="#7.19"><stddef.h></a>
(<a href="#7.19">7.19</a>).
<a name="6.5.7" href="#6.5.7"><b> 6.5.7 Bitwise shift operators</b></a>
- Syntax
+<b> Syntax</b>
1 shift-expression:
additive-expression
shift-expression << additive-expression
shift-expression >> additive-expression
- Constraints
+<b> Constraints</b>
2 Each of the operands shall have integer type.
- Semantics
+<b> Semantics</b>
3 The integer promotions are performed on each of the operands. The type of the result is
that of the promoted left operand. If the value of the right operand is negative or is
- 106) Another way to approach pointer arithmetic is first to convert the pointer(s) to character pointer(s): In
+ <sup><a name="note106" href="#note106"><b>106)</b></a></sup> Another way to approach pointer arithmetic is first to convert the pointer(s) to character pointer(s): In
this scheme the integer expression added to or subtracted from the converted pointer is first multiplied
by the size of the object originally pointed to, and the resulting pointer is converted back to the
original type. For pointer subtraction, the result of the difference between the character pointers is
another object in the program) just after the end of the object in order to satisfy the ''one past the last
element'' requirements.
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greater than or equal to the width of the promoted left operand, the behavior is undefined.
4 The result of E1 << E2 is E1 left-shifted E2 bit positions; vacated bits are filled with
part of the quotient of E1 / 2E2 . If E1 has a signed type and a negative value, the
resulting value is implementation-defined.
<a name="6.5.8" href="#6.5.8"><b> 6.5.8 Relational operators</b></a>
- Syntax
+<b> Syntax</b>
1 relational-expression:
shift-expression
relational-expression < shift-expression
relational-expression > shift-expression
relational-expression <= shift-expression
relational-expression >= shift-expression
- Constraints
+<b> Constraints</b>
2 One of the following shall hold:
-- both operands have real type; or *
-- both operands are pointers to qualified or unqualified versions of compatible object
types.
- Semantics
+<b> Semantics</b>
3 If both of the operands have arithmetic type, the usual arithmetic conversions are
performed.
4 For the purposes of these operators, a pointer to an object that is not an element of an
declared earlier in the structure, and pointers to array elements with larger subscript
values compare greater than pointers to elements of the same array with lower subscript
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values. All pointers to members of the same union object compare equal. If the
expression P points to an element of an array object and the expression Q points to the
P. In all other cases, the behavior is undefined.
6 Each of the operators < (less than), > (greater than), <= (less than or equal to), and >=
(greater than or equal to) shall yield 1 if the specified relation is true and 0 if it is
- false.107) The result has type int.
+ false.<sup><a href="#note107"><b>107)</b></a></sup> The result has type int.
<a name="6.5.9" href="#6.5.9"><b> 6.5.9 Equality operators</b></a>
- Syntax
+<b> Syntax</b>
1 equality-expression:
relational-expression
equality-expression == relational-expression
equality-expression != relational-expression
- Constraints
+<b> Constraints</b>
2 One of the following shall hold:
-- both operands have arithmetic type;
-- both operands are pointers to qualified or unqualified versions of compatible types;
-- one operand is a pointer to an object type and the other is a pointer to a qualified or
unqualified version of void; or
-- one operand is a pointer and the other is a null pointer constant.
- Semantics
+<b> Semantics</b>
3 The == (equal to) and != (not equal to) operators are analogous to the relational
- operators except for their lower precedence.108) Each of the operators yields 1 if the
+ operators except for their lower precedence.<sup><a href="#note108"><b>108)</b></a></sup> Each of the operators yields 1 if the
specified relation is true and 0 if it is false. The result has type int. For any pair of
operands, exactly one of the relations is true.
4 If both of the operands have arithmetic type, the usual arithmetic conversions are
- 107) The expression a<b<c is not interpreted as in ordinary mathematics. As the syntax indicates, it
+ <sup><a name="note107" href="#note107"><b>107)</b></a></sup> The expression a<b<c is not interpreted as in ordinary mathematics. As the syntax indicates, it
means (a<b)<c; in other words, ''if a is less than b, compare 1 to c; otherwise, compare 0 to c''.
- 108) Because of the precedences, a<b == c<d is 1 whenever a<b and c<d have the same truth-value.
+ <sup><a name="note108" href="#note108"><b>108)</b></a></sup> Because of the precedences, a<b == c<d is 1 whenever a<b and c<d have the same truth-value.
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5 Otherwise, at least one operand is a pointer. If one operand is a pointer and the other is a
null pointer constant, the null pointer constant is converted to the type of the pointer. If
both are pointers to one past the last element of the same array object, or one is a pointer
to one past the end of one array object and the other is a pointer to the start of a different
array object that happens to immediately follow the first array object in the address
- space.109)
+ space.<sup><a href="#note109"><b>109)</b></a></sup>
7 For the purposes of these operators, a pointer to an object that is not an element of an
array behaves the same as a pointer to the first element of an array of length one with the
type of the object as its element type.
<a name="6.5.10" href="#6.5.10"><b> 6.5.10 Bitwise AND operator</b></a>
- Syntax
+<b> Syntax</b>
1 AND-expression:
equality-expression
AND-expression & equality-expression
- Constraints
+<b> Constraints</b>
2 Each of the operands shall have integer type.
- Semantics
+<b> Semantics</b>
3 The usual arithmetic conversions are performed on the operands.
4 The result of the binary & operator is the bitwise AND of the operands (that is, each bit in
the result is set if and only if each of the corresponding bits in the converted operands is
- 109) Two objects may be adjacent in memory because they are adjacent elements of a larger array or
+ <sup><a name="note109" href="#note109"><b>109)</b></a></sup> Two objects may be adjacent in memory because they are adjacent elements of a larger array or
adjacent members of a structure with no padding between them, or because the implementation chose
to place them so, even though they are unrelated. If prior invalid pointer operations (such as accesses
outside array bounds) produced undefined behavior, subsequent comparisons also produce undefined
behavior.
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<a name="6.5.11" href="#6.5.11"><b> 6.5.11 Bitwise exclusive OR operator</b></a>
- Syntax
+<b> Syntax</b>
1 exclusive-OR-expression:
AND-expression
exclusive-OR-expression ^ AND-expression
- Constraints
+<b> Constraints</b>
2 Each of the operands shall have integer type.
- Semantics
+<b> Semantics</b>
3 The usual arithmetic conversions are performed on the operands.
4 The result of the ^ operator is the bitwise exclusive OR of the operands (that is, each bit
in the result is set if and only if exactly one of the corresponding bits in the converted
operands is set).
<a name="6.5.12" href="#6.5.12"><b> 6.5.12 Bitwise inclusive OR operator</b></a>
- Syntax
+<b> Syntax</b>
1 inclusive-OR-expression:
exclusive-OR-expression
inclusive-OR-expression | exclusive-OR-expression
- Constraints
+<b> Constraints</b>
2 Each of the operands shall have integer type.
- Semantics
+<b> Semantics</b>
3 The usual arithmetic conversions are performed on the operands.
4 The result of the | operator is the bitwise inclusive OR of the operands (that is, each bit in
the result is set if and only if at least one of the corresponding bits in the converted
operands is set).
-
-
-
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<a name="6.5.13" href="#6.5.13"><b> 6.5.13 Logical AND operator</b></a>
- Syntax
+<b> Syntax</b>
1 logical-AND-expression:
inclusive-OR-expression
logical-AND-expression && inclusive-OR-expression
- Constraints
+<b> Constraints</b>
2 Each of the operands shall have scalar type.
- Semantics
+<b> Semantics</b>
3 The && operator shall yield 1 if both of its operands compare unequal to 0; otherwise, it
yields 0. The result has type int.
4 Unlike the bitwise binary & operator, the && operator guarantees left-to-right evaluation;
the first and second operands. If the first operand compares equal to 0, the second
operand is not evaluated.
<a name="6.5.14" href="#6.5.14"><b> 6.5.14 Logical OR operator</b></a>
- Syntax
+<b> Syntax</b>
1 logical-OR-expression:
logical-AND-expression
logical-OR-expression || logical-AND-expression
- Constraints
+<b> Constraints</b>
2 Each of the operands shall have scalar type.
- Semantics
+<b> Semantics</b>
3 The || operator shall yield 1 if either of its operands compare unequal to 0; otherwise, it
yields 0. The result has type int.
4 Unlike the bitwise | operator, the || operator guarantees left-to-right evaluation; if the
and second operands. If the first operand compares unequal to 0, the second operand is
not evaluated.
-
-
-
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<a name="6.5.15" href="#6.5.15"><b> 6.5.15 Conditional operator</b></a>
- Syntax
+<b> Syntax</b>
1 conditional-expression:
logical-OR-expression
logical-OR-expression ? expression : conditional-expression
- Constraints
+<b> Constraints</b>
2 The first operand shall have scalar type.
3 One of the following shall hold for the second and third operands:
-- both operands have arithmetic type;
-- one operand is a pointer and the other is a null pointer constant; or
-- one operand is a pointer to an object type and the other is a pointer to a qualified or
unqualified version of void.
- Semantics
+<b> Semantics</b>
4 The first operand is evaluated; there is a sequence point between its evaluation and the
evaluation of the second or third operand (whichever is evaluated). The second operand
is evaluated only if the first compares unequal to 0; the third operand is evaluated only if
the first compares equal to 0; the result is the value of the second or third operand
- (whichever is evaluated), converted to the type described below.110) *
+ (whichever is evaluated), converted to the type described below.<sup><a href="#note110"><b>110)</b></a></sup> *
5 If both the second and third operands have arithmetic type, the result type that would be
determined by the usual arithmetic conversions, were they applied to those two operands,
is the type of the result. If both the operands have structure or union type, the result has
is a pointer to void or a qualified version of void, in which case the result type is a
pointer to an appropriately qualified version of void.
- 110) A conditional expression does not yield an lvalue.
+ <sup><a name="note110" href="#note110"><b>110)</b></a></sup> A conditional expression does not yield an lvalue.
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7 EXAMPLE The common type that results when the second and third operands are pointers is determined
in two independent stages. The appropriate qualifiers, for example, do not depend on whether the two
vp ip void *
<a name="6.5.16" href="#6.5.16"><b> 6.5.16 Assignment operators</b></a>
- Syntax
+<b> Syntax</b>
1 assignment-expression:
conditional-expression
unary-expression assignment-operator assignment-expression
assignment-operator: one of
= *= /= %= += -= <<= >>= &= ^= |=
- Constraints
+<b> Constraints</b>
2 An assignment operator shall have a modifiable lvalue as its left operand.
- Semantics
+<b> Semantics</b>
3 An assignment operator stores a value in the object designated by the left operand. An
- assignment expression has the value of the left operand after the assignment,111) but is not
+ assignment expression has the value of the left operand after the assignment,<sup><a href="#note111"><b>111)</b></a></sup> but is not
an lvalue. The type of an assignment expression is the type the left operand would have
after lvalue conversion. The side effect of updating the stored value of the left operand is
sequenced after the value computations of the left and right operands. The evaluations of
- 111) The implementation is permitted to read the object to determine the value but is not required to, even
+ <sup><a name="note111" href="#note111"><b>111)</b></a></sup> The implementation is permitted to read the object to determine the value but is not required to, even
when the object has volatile-qualified type.
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<a name="6.5.16.1" href="#6.5.16.1"><b> 6.5.16.1 Simple assignment</b></a>
- Constraints
-1 One of the following shall hold:112)
+<b> Constraints</b>
+1 One of the following shall hold:<sup><a href="#note112"><b>112)</b></a></sup>
-- the left operand has atomic, qualified, or unqualified arithmetic type, and the right has
arithmetic type;
-- the left operand has an atomic, qualified, or unqualified version of a structure or union
pointer constant; or
-- the left operand has type atomic, qualified, or unqualified _Bool, and the right is a
pointer.
- Semantics
+<b> Semantics</b>
2 In simple assignment (=), the value of the right operand is converted to the type of the
assignment expression and replaces the value stored in the object designated by the left
operand.
- 112) The asymmetric appearance of these constraints with respect to type qualifiers is due to the conversion
+ <sup><a name="note112" href="#note112"><b>112)</b></a></sup> The asymmetric appearance of these constraints with respect to type qualifiers is due to the conversion
(specified in <a href="#6.3.2.1">6.3.2.1</a>) that changes lvalues to ''the value of the expression'' and thus removes any type
qualifiers that were applied to the type category of the expression (for example, it removes const but
not volatile from the type int volatile * const).
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int f(void);
char c;
value of the const object c.
<a name="6.5.16.2" href="#6.5.16.2"><b> 6.5.16.2 Compound assignment</b></a>
- Constraints
+<b> Constraints</b>
1 For the operators += and -= only, either the left operand shall be an atomic, qualified, or
unqualified pointer to a complete object type, and the right shall have integer type; or the
left operand shall have atomic, qualified, or unqualified arithmetic type, and the right
arithmetic type, and (considering the type the left operand would have after lvalue
conversion) each operand shall have arithmetic type consistent with those allowed by the
corresponding binary operator.
- Semantics
+<b> Semantics</b>
3 A compound assignment of the form E1 op = E2 is equivalent to the simple assignment
expression E1 = E1 op (E2), except that the lvalue E1 is evaluated only once, and with
respect to an indeterminately-sequenced function call, the operation of a compound
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+
+[<a name="p103" href="#p103">page 103</a>] (<a href="#Contents">Contents</a>)
assignment is a single evaluation. If E1 has an atomic type, compound assignment is a
read-modify-write operation with memory_order_seq_cst memory order
- semantics.113)
+ semantics.<sup><a href="#note113"><b>113)</b></a></sup>
<a name="6.5.17" href="#6.5.17"><b> 6.5.17 Comma operator</b></a>
- Syntax
+<b> Syntax</b>
1 expression:
assignment-expression
expression , assignment-expression
- Semantics
+<b> Semantics</b>
2 The left operand of a comma operator is evaluated as a void expression; there is a
sequence point between its evaluation and that of the right operand. Then the right
- operand is evaluated; the result has its type and value.114) *
+ operand is evaluated; the result has its type and value.<sup><a href="#note114"><b>114)</b></a></sup> *
3 EXAMPLE As indicated by the syntax, the comma operator (as described in this subclause) cannot
appear in contexts where a comma is used to separate items in a list (such as arguments to functions or lists
of initializers). On the other hand, it can be used within a parenthesized expression or within the second
- 113) Where a pointer to an atomic object can be formed, this is equivalent to the following code sequence
+ <sup><a name="note113" href="#note113"><b>113)</b></a></sup> Where a pointer to an atomic object can be formed, this is equivalent to the following code sequence
where T is the type of E1:
T tmp = E1;
T result;
result = tmp op (E2);
} while (!atomic_compare_exchange_strong(&E1, &tmp, result));
with result being the result of the operation.
- 114) A comma operator does not yield an lvalue.
+ <sup><a name="note114" href="#note114"><b>114)</b></a></sup> A comma operator does not yield an lvalue.
-[<a name="
#p104" href="p104">page 104</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p104" href="#p104">page 104</a>] (<a href="#Contents">Contents</a>)
<a name="6.6" href="#6.6"><b> 6.6 Constant expressions</b></a>
- Syntax
+<b> Syntax</b>
1 constant-expression:
conditional-expression
- Description
+<b> Description</b>
2 A constant expression can be evaluated during translation rather than runtime, and
accordingly may be used in any place that a constant may be.
- Constraints
+<b> Constraints</b>
3 Constant expressions shall not contain assignment, increment, decrement, function-call,
or comma operators, except when they are contained within a subexpression that is not
- evaluated.115)
+ evaluated.<sup><a href="#note115"><b>115)</b></a></sup>
4 Each constant expression shall evaluate to a constant that is in the range of representable
values for its type.
- Semantics
+<b> Semantics</b>
5 An expression that evaluates to a constant is required in several contexts. If a floating
expression is evaluated in the translation environment, the arithmetic precision and range
shall be at least as great as if the expression were being evaluated in the execution
- environment.116)
-6 An integer constant expression117) shall have integer type and shall only have operands
+ environment.<sup><a href="#note116"><b>116)</b></a></sup>
+6 An integer constant expression<sup><a href="#note117"><b>117)</b></a></sup> shall have integer type and shall only have operands
that are integer constants, enumeration constants, character constants, sizeof
expressions whose results are integer constants, and floating constants that are the
immediate operands of casts. Cast operators in an integer constant expression shall only
-
115) The operand of a sizeof operator is usually not evaluated (<a href="#6.5.3.4">6.5.3.4</a>).
- 116) The use of evaluation formats as characterized by FLT_EVAL_METHOD also applies to evaluation in
+
<sup><a name="note115" href="#note115"><b>115)</b></a></sup> The operand of a sizeof operator is usually not evaluated (<a href="#6.5.3.4">6.5.3.4</a>).
+ <sup><a name="note116" href="#note116"><b>116)</b></a></sup> The use of evaluation formats as characterized by FLT_EVAL_METHOD also applies to evaluation in
the translation environment.
- 117) An integer constant expression is required in a number of contexts such as the size of a bit-field
+ <sup><a name="note117" href="#note117"><b>117)</b></a></sup> An integer constant expression is required in a number of contexts such as the size of a bit-field
member of a structure, the value of an enumeration constant, and the size of a non-variable length
array. Further constraints that apply to the integer constant expressions used in conditional-inclusion
preprocessing directives are discussed in <a href="#6.10.1">6.10.1</a>.
-[<a name="
#p105" href="p105">page 105</a>] (<a href="#Contents">Contents</a>)
+[<a name="
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-- a null pointer constant,
-- an address constant, or
accessed by use of these operators.
10 An implementation may accept other forms of constant expressions.
11 The semantic rules for the evaluation of a constant expression are the same as for
- nonconstant expressions.118)
+ nonconstant expressions.<sup><a href="#note118"><b>118)</b></a></sup>
Forward references: array declarators (<a href="#6.7.6.2">6.7.6.2</a>), initialization (<a href="#6.7.9">6.7.9</a>).
- 118) Thus, in the following initialization,
+ <sup><a name="note118" href="#note118"><b>118)</b></a></sup> Thus, in the following initialization,
static int i = 2 || 1 / 0;
the expression is a valid integer constant expression with value one.
-[<a name="
#p106" href="p106">page 106</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p106" href="#p106">page 106</a>] (<a href="#Contents">Contents</a>)
<a name="6.7" href="#6.7"><b> 6.7 Declarations</b></a>
- Syntax
+<b> Syntax</b>
1 declaration:
declaration-specifiers init-declarator-listopt ;
static_assert-declaration
init-declarator:
declarator
declarator = initializer
- Constraints
+<b> Constraints</b>
2 A declaration other than a static_assert declaration shall declare at least a declarator
(other than the parameters of a function or the members of a structure or union), a tag, or
the members of an enumeration.
may be redeclared as specified in <a href="#6.7.2.3">6.7.2.3</a>.
4 All declarations in the same scope that refer to the same object or function shall specify
compatible types.
- Semantics
+<b> Semantics</b>
5 A declaration specifies the interpretation and attributes of a set of identifiers. A definition
of an identifier is a declaration for that identifier that:
-- for an object, causes storage to be reserved for that object;
- -- for a function, includes the function body;119)
+ -- for a function, includes the function body;<sup><a href="#note119"><b>119)</b></a></sup>
-
119) Function definitions have a different syntax, described in <a href="#6.9.1">6.9.1</a>.
+
<sup><a name="note119" href="#note119"><b>119)</b></a></sup> Function definitions have a different syntax, described in <a href="#6.9.1">6.9.1</a>.
-[<a name="
#p107" href="p107">page 107</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p107" href="#p107">page 107</a>] (<a href="#Contents">Contents</a>)
-- for an enumeration constant or typedef name, is the (only) declaration of the
identifier.
Forward references: declarators (<a href="#6.7.6">6.7.6</a>), enumeration specifiers (<a href="#6.7.2.2">6.7.2.2</a>), initialization
(<a href="#6.7.9">6.7.9</a>), type names (<a href="#6.7.7">6.7.7</a>), type qualifiers (<a href="#6.7.3">6.7.3</a>).
<a name="6.7.1" href="#6.7.1"><b> 6.7.1 Storage-class specifiers</b></a>
- Syntax
+<b> Syntax</b>
1 storage-class-specifier:
typedef
extern
_Thread_local
auto
register
- Constraints
+<b> Constraints</b>
2 At most, one storage-class specifier may be given in the declaration specifiers in a
- declaration, except that _Thread_local may appear with static or extern.120)
+ declaration, except that _Thread_local may appear with static or extern.<sup><a href="#note120"><b>120)</b></a></sup>
3 In the declaration of an object with block scope, if the declaration specifiers include
_Thread_local, they shall also include either static or extern. If
_Thread_local appears in any declaration of an object, it shall be present in every
declaration of that object.
- Semantics
+<b> Semantics</b>
4 The typedef specifier is called a ''storage-class specifier'' for syntactic convenience
only; it is discussed in <a href="#6.7.8">6.7.8</a>. The meanings of the various linkages and storage durations
were discussed in <a href="#6.2.2">6.2.2</a> and <a href="#6.2.4">6.2.4</a>.
-
120) See ''future language directions'' (<a href="#6.11.5">6.11.5</a>).
+
<sup><a name="note120" href="#note120"><b>120)</b></a></sup> See ''future language directions'' (<a href="#6.11.5">6.11.5</a>).
-[<a name="
#p108" href="p108">page 108</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p108" href="#p108">page 108</a>] (<a href="#Contents">Contents</a>)
5 A declaration of an identifier for an object with storage-class specifier register
suggests that access to the object be as fast as possible. The extent to which such
- suggestions are effective is implementation-defined.121)
+ suggestions are effective is implementation-defined.<sup><a href="#note121"><b>121)</b></a></sup>
6 The declaration of an identifier for a function that has block scope shall have no explicit
storage-class specifier other than extern.
7 If an aggregate or union object is declared with a storage-class specifier other than
or union member objects.
Forward references: type definitions (<a href="#6.7.8">6.7.8</a>).
<a name="6.7.2" href="#6.7.2"><b> 6.7.2 Type specifiers</b></a>
- Syntax
+<b> Syntax</b>
1 type-specifier:
void
char
struct-or-union-specifier
enum-specifier
typedef-name
- Constraints
+<b> Constraints</b>
2 At least one type specifier shall be given in the declaration specifiers in each declaration,
and in the specifier-qualifier list in each struct declaration and type name. Each list of
- 121) The implementation may treat any register declaration simply as an auto declaration. However,
+ <sup><a name="note121" href="#note121"><b>121)</b></a></sup> The implementation may treat any register declaration simply as an auto declaration. However,
whether or not addressable storage is actually used, the address of any part of an object declared with
storage-class specifier register cannot be computed, either explicitly (by use of the unary &
operator as discussed in <a href="#6.5.3.2">6.5.3.2</a>) or implicitly (by converting an array name to a pointer as discussed in
<a href="#6.3.2.1">6.3.2.1</a>). Thus, the only operator that can be applied to an array declared with storage-class specifier
register is sizeof.
-[<a name="
#p109" href="p109">page 109</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p109" href="#p109">page 109</a>] (<a href="#Contents">Contents</a>)
type specifiers shall be one of the following multisets (delimited by commas, when there
is more than one multiset per item); the type specifiers may occur in any order, possibly
3 The type specifier _Complex shall not be used if the implementation does not support
complex types (see <a href="#6.10.8.3">6.10.8.3</a>).
+[<a name="p110" href="#p110">page 110</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p110" href="p110">page 110</a>] (<a href="#Contents">Contents</a>)
-
- Semantics
+<b> Semantics</b>
4 Specifiers for structures, unions, enumerations, and atomic types are discussed in <a href="#6.7.2.1">6.7.2.1</a>
through <a href="#6.7.2.4">6.7.2.4</a>. Declarations of typedef names are discussed in <a href="#6.7.8">6.7.8</a>. The
characteristics of the other types are discussed in <a href="#6.2.5">6.2.5</a>.
Forward references: atomic type specifiers (<a href="#6.7.2.4">6.7.2.4</a>), enumeration specifiers (<a href="#6.7.2.2">6.7.2.2</a>),
structure and union specifiers (<a href="#6.7.2.1">6.7.2.1</a>), tags (<a href="#6.7.2.3">6.7.2.3</a>), type definitions (<a href="#6.7.8">6.7.8</a>).
<a name="6.7.2.1" href="#6.7.2.1"><b> 6.7.2.1 Structure and union specifiers</b></a>
- Syntax
+<b> Syntax</b>
1 struct-or-union-specifier:
struct-or-union identifieropt { struct-declaration-list }
struct-or-union identifier
struct-declarator:
declarator
declaratoropt : constant-expression
- Constraints
+<b> Constraints</b>
2 A struct-declaration that does not declare an anonymous structure or anonymous union
shall contain a struct-declarator-list.
-
-[<a name="#p111" href="p111">page 111</a>] (<a href="#Contents">Contents</a>)
+[<a name="p111" href="#p111">page 111</a>] (<a href="#Contents">Contents</a>)
3 A structure or union shall not contain a member with incomplete or function type (hence,
a structure shall not contain an instance of itself, but may contain a pointer to an instance
element of an array.
4 The expression that specifies the width of a bit-field shall be an integer constant
expression with a nonnegative value that does not exceed the width of an object of the
- type that would be specified were the colon and expression omitted.122) If the value is
+ type that would be specified were the colon and expression omitted.<sup><a href="#note122"><b>122)</b></a></sup> If the value is
zero, the declaration shall have no declarator.
5 A bit-field shall have a type that is a qualified or unqualified version of _Bool, signed
int, unsigned int, or some other implementation-defined type. It is
implementation-defined whether atomic types are permitted.
- Semantics
+<b> Semantics</b>
6 As discussed in <a href="#6.2.5">6.2.5</a>, a structure is a type consisting of a sequence of members, whose
storage is allocated in an ordered sequence, and a union is a type consisting of a sequence
of members whose storage overlap.
The type is incomplete until immediately after the } that terminates the list, and complete
thereafter.
9 A member of a structure or union may have any complete object type other than a
- variably modified type.123) In addition, a member may be declared to consist of a
+ variably modified type.<sup><a href="#note123"><b>123)</b></a></sup> In addition, a member may be declared to consist of a
specified number of bits (including a sign bit, if any). Such a member is called a
- bit-field;124) its width is preceded by a colon.
+ bit-field;<sup><a href="#note124"><b>124)</b></a></sup> its width is preceded by a colon.
10 A bit-field is interpreted as having a signed or unsigned integer type consisting of the
- specified number of bits.125) If the value 0 or 1 is stored into a nonzero-width bit-field of
+ specified number of bits.<sup><a href="#note125"><b>125)</b></a></sup> If the value 0 or 1 is stored into a nonzero-width bit-field of
- 122) While the number of bits in a _Bool object is at least CHAR_BIT, the width (number of sign and
+ <sup><a name="note122" href="#note122"><b>122)</b></a></sup> While the number of bits in a _Bool object is at least CHAR_BIT, the width (number of sign and
value bits) of a _Bool may be just 1 bit.
- 123) A structure or union cannot contain a member with a variably modified type because member names
+ <sup><a name="note123" href="#note123"><b>123)</b></a></sup> A structure or union cannot contain a member with a variably modified type because member names
are not ordinary identifiers as defined in <a href="#6.2.3">6.2.3</a>.
- 124) The unary & (address-of) operator cannot be applied to a bit-field object; thus, there are no pointers to
+ <sup><a name="note124" href="#note124"><b>124)</b></a></sup> The unary & (address-of) operator cannot be applied to a bit-field object; thus, there are no pointers to
or arrays of bit-field objects.
-[<a name="
#p112" href="p112">page 112</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p112" href="#p112">page 112</a>] (<a href="#Contents">Contents</a>)
type _Bool, the value of the bit-field shall compare equal to the value stored; a _Bool
bit-field has the semantics of a _Bool.
low-order or low-order to high-order) is implementation-defined. The alignment of the
addressable storage unit is unspecified.
12 A bit-field declaration with no declarator, but only a colon and a width, indicates an
- unnamed bit-field.126) As a special case, a bit-field structure member with a width of 0
+ unnamed bit-field.<sup><a href="#note126"><b>126)</b></a></sup> As a special case, a bit-field structure member with a width of 0
indicates that no further bit-field is to be packed into the unit in which the previous bit-
field, if any, was placed.
13 An unnamed member of structure type with no tag is called an anonymous structure; an
have an incomplete array type; this is called a flexible array member. In most situations,
-
125) As specified in <a href="#6.7.2">6.7.2</a> above, if the actual type specifier used is int or a typedef-name defined as int,
+
<sup><a name="note125" href="#note125"><b>125)</b></a></sup> As specified in <a href="#6.7.2">6.7.2</a> above, if the actual type specifier used is int or a typedef-name defined as int,
then it is implementation-defined whether the bit-field is signed or unsigned.
- 126) An unnamed bit-field structure member is useful for padding to conform to externally imposed
+ <sup><a name="note126" href="#note126"><b>126)</b></a></sup> An unnamed bit-field structure member is useful for padding to conform to externally imposed
layouts.
-[<a name="
#p113" href="p113">page 113</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p113" href="#p113">page 113</a>] (<a href="#Contents">Contents</a>)
the flexible array member is ignored. In particular, the size of the structure is as if the
flexible array member were omitted except that it may have more trailing padding than
in which case the assignment would be legitimate. Nevertheless, it cannot appear in strictly conforming
code.
-[<a name="
#p114" href="p114">page 114</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p114" href="#p114">page 114</a>] (<a href="#Contents">Contents</a>)
22 After the further declaration:
struct ss { int n; };
Forward references: declarators (<a href="#6.7.6">6.7.6</a>), tags (<a href="#6.7.2.3">6.7.2.3</a>).
-
-
-
-[<a name="#p115" href="p115">page 115</a>] (<a href="#Contents">Contents</a>)
+[<a name="p115" href="#p115">page 115</a>] (<a href="#Contents">Contents</a>)
<a name="6.7.2.2" href="#6.7.2.2"><b> 6.7.2.2 Enumeration specifiers</b></a>
- Syntax
+<b> Syntax</b>
1 enum-specifier:
enum identifieropt { enumerator-list }
enum identifieropt { enumerator-list , }
enumerator:
enumeration-constant
enumeration-constant = constant-expression
- Constraints
+<b> Constraints</b>
2 The expression that defines the value of an enumeration constant shall be an integer
constant expression that has a value representable as an int.
- Semantics
+<b> Semantics</b>
3 The identifiers in an enumerator list are declared as constants that have type int and
- may appear wherever such are permitted.127) An enumerator with = defines its
+ may appear wherever such are permitted.<sup><a href="#note127"><b>127)</b></a></sup> An enumerator with = defines its
enumeration constant as the value of the constant expression. If the first enumerator has
no =, the value of its enumeration constant is 0. Each subsequent enumerator with no =
defines its enumeration constant as the value of the constant expression obtained by
= may produce enumeration constants with values that duplicate other values in the same
enumeration.) The enumerators of an enumeration are also known as its members.
4 Each enumerated type shall be compatible with char, a signed integer type, or an
- unsigned integer type. The choice of type is implementation-defined,128) but shall be
+ unsigned integer type. The choice of type is implementation-defined,<sup><a href="#note128"><b>128)</b></a></sup> but shall be
capable of representing the values of all the members of the enumeration. The
enumerated type is incomplete until immediately after the } that terminates the list of
enumerator declarations, and complete thereafter.
- 127) Thus, the identifiers of enumeration constants declared in the same scope shall all be distinct from
+ <sup><a name="note127" href="#note127"><b>127)</b></a></sup> Thus, the identifiers of enumeration constants declared in the same scope shall all be distinct from
each other and from other identifiers declared in ordinary declarators.
- 128) An implementation may delay the choice of which integer type until all enumeration constants have
+ <sup><a name="note128" href="#note128"><b>128)</b></a></sup> An implementation may delay the choice of which integer type until all enumeration constants have
been seen.
-[<a name="
#p116" href="p116">page 116</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p116" href="#p116">page 116</a>] (<a href="#Contents">Contents</a>)
5 EXAMPLE The following fragment:
enum hue { chartreuse, burgundy, claret=20, winedark };
Forward references: tags (<a href="#6.7.2.3">6.7.2.3</a>).
<a name="6.7.2.3" href="#6.7.2.3"><b> 6.7.2.3 Tags</b></a>
- Constraints
+<b> Constraints</b>
1 A specific type shall have its content defined at most once.
2 Where two declarations that use the same tag declare the same type, they shall both use
the same choice of struct, union, or enum.
3 A type specifier of the form
enum identifier
without an enumerator list shall only appear after the type it specifies is complete.
- Semantics
+<b> Semantics</b>
4 All declarations of structure, union, or enumerated types that have the same scope and
use the same tag declare the same type. Irrespective of whether there is a tag or what
- other declarations of the type are in the same translation unit, the type is incomplete129)
+ other declarations of the type are in the same translation unit, the type is incomplete<sup><a href="#note129"><b>129)</b></a></sup>
until immediately after the closing brace of the list defining the content, and complete
thereafter.
5 Two declarations of structure, union, or enumerated types which are in different scopes or
- 129) An incomplete type may only by used when the size of an object of that type is not needed. It is not
+ <sup><a name="note129" href="#note129"><b>129)</b></a></sup> An incomplete type may only by used when the size of an object of that type is not needed. It is not
needed, for example, when a typedef name is declared to be a specifier for a structure or union, or
when a pointer to or a function returning a structure or union is being declared. (See incomplete types
in <a href="#6.2.5">6.2.5</a>.) The specification has to be complete before such a function is called or defined.
-[<a name="
#p117" href="p117">page 117</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p117" href="#p117">page 117</a>] (<a href="#Contents">Contents</a>)
struct-or-union identifieropt { struct-declaration-list }
or
or
enum identifieropt { enumerator-list , }
declares a structure, union, or enumerated type. The list defines the structure content,
- union content, or enumeration content. If an identifier is provided,130) the type specifier
+ union content, or enumeration content. If an identifier is provided,<sup><a href="#note130"><b>130)</b></a></sup> the type specifier
also declares the identifier to be the tag of that type.
7 A declaration of the form
struct-or-union identifier ;
- specifies a structure or union type and declares the identifier as a tag of that type.131)
+ specifies a structure or union type and declares the identifier as a tag of that type.<sup><a href="#note131"><b>131)</b></a></sup>
8 If a type specifier of the form
struct-or-union identifier
occurs other than as part of one of the above forms, and no other declaration of the
- 130) If there is no identifier, the type can, within the translation unit, only be referred to by the declaration
+ <sup><a name="note130" href="#note130"><b>130)</b></a></sup> If there is no identifier, the type can, within the translation unit, only be referred to by the declaration
of which it is a part. Of course, when the declaration is of a typedef name, subsequent declarations
can make use of that typedef name to declare objects having the specified structure, union, or
enumerated type.
- 131) A similar construction with enum does not exist.
+ <sup><a name="note131" href="#note131"><b>131)</b></a></sup> A similar construction with enum does not exist.
-[<a name="
#p118" href="p118">page 118</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p118" href="#p118">page 118</a>] (<a href="#Contents">Contents</a>)
struct tnode s, *sp;
declares s to be an object of the given type and sp to be a pointer to an object of the given type. With
Forward references: declarators (<a href="#6.7.6">6.7.6</a>), type definitions (<a href="#6.7.8">6.7.8</a>).
<a name="6.7.2.4" href="#6.7.2.4"><b> 6.7.2.4 Atomic type specifiers</b></a>
- Syntax
+<b> Syntax</b>
1 atomic-type-specifier:
_Atomic ( type-name )
- Constraints
+<b> Constraints</b>
2 Atomic type specifiers shall not be used if the implementation does not support atomic
types (see <a href="#6.10.8.3">6.10.8.3</a>).
3 The type name in an atomic type specifier shall not refer to an array type, a function type,
an atomic type, or a qualified type.
- Semantics
+<b> Semantics</b>
4 The properties associated with atomic types are meaningful only for expressions that are
lvalues. If the _Atomic keyword is immediately followed by a left parenthesis, it is
interpreted as a type specifier (with a type name), not as a type qualifier.
-
-
-
-[<a name="#p119" href="p119">page 119</a>] (<a href="#Contents">Contents</a>)
+[<a name="p119" href="#p119">page 119</a>] (<a href="#Contents">Contents</a>)
<a name="6.7.3" href="#6.7.3"><b> 6.7.3 Type qualifiers</b></a>
- Syntax
+<b> Syntax</b>
1 type-qualifier:
const
restrict
volatile
_Atomic
- Constraints
+<b> Constraints</b>
2 Types other than pointer types whose referenced type is an object type shall not be
restrict-qualified.
3 The type modified by the _Atomic qualifier shall not be an array type or a function
type.
- Semantics
+<b> Semantics</b>
4 The properties associated with qualified types are meaningful only for expressions that
- are lvalues.132)
+ are lvalues.<sup><a href="#note132"><b>132)</b></a></sup>
5 If the same qualifier appears more than once in the same specifier-qualifier-list, either
directly or via one or more typedefs, the behavior is the same as if it appeared only
once. If other qualifiers appear along with the _Atomic qualifier in a specifier-qualifier-
6 If an attempt is made to modify an object defined with a const-qualified type through use
of an lvalue with non-const-qualified type, the behavior is undefined. If an attempt is
made to refer to an object defined with a volatile-qualified type through use of an lvalue
- with non-volatile-qualified type, the behavior is undefined.133)
+ with non-volatile-qualified type, the behavior is undefined.<sup><a href="#note133"><b>133)</b></a></sup>
7 An object that has volatile-qualified type may be modified in ways unknown to the
implementation or have other unknown side effects. Therefore any expression referring
to such an object shall be evaluated strictly according to the rules of the abstract machine,
- 132) The implementation may place a const object that is not volatile in a read-only region of
+ <sup><a name="note132" href="#note132"><b>132)</b></a></sup> The implementation may place a const object that is not volatile in a read-only region of
storage. Moreover, the implementation need not allocate storage for such an object if its address is
never used.
- 133) This applies to those objects that behave as if they were defined with qualified types, even if they are
+ <sup><a name="note133" href="#note133"><b>133)</b></a></sup> This applies to those objects that behave as if they were defined with qualified types, even if they are
never actually defined as objects in the program (such as an object at a memory-mapped input/output
address).
-[<a name="
#p120" href="p120">page 120</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p120" href="#p120">page 120</a>] (<a href="#Contents">Contents</a>)
- unknown factors mentioned previously.134) What constitutes an access to an object that
+ unknown factors mentioned previously.<sup><a href="#note134"><b>134)</b></a></sup> What constitutes an access to an object that
has volatile-qualified type is implementation-defined.
8 An object that is accessed through a restrict-qualified pointer has a special association
with that pointer. This association, defined in <a href="#6.7.3.1">6.7.3.1</a> below, requires that all accesses to
- that object use, directly or indirectly, the value of that particular pointer.135) The intended
+ that object use, directly or indirectly, the value of that particular pointer.<sup><a href="#note135"><b>135)</b></a></sup> The intended
use of the restrict qualifier (like the register storage class) is to promote
optimization, and deleting all instances of the qualifier from all preprocessing translation
units composing a conforming program does not change its meaning (i.e., observable
behavior).
9 If the specification of an array type includes any type qualifiers, the element type is so-
qualified, not the array type. If the specification of a function type includes any type
- qualifiers, the behavior is undefined.136)
+ qualifiers, the behavior is undefined.<sup><a href="#note136"><b>136)</b></a></sup>
10 For two qualified types to be compatible, both shall have the identically qualified version
of a compatible type; the order of type qualifiers within a list of specifiers or qualifiers
does not affect the specified type.
- 134) A volatile declaration may be used to describe an object corresponding to a memory-mapped
+ <sup><a name="note134" href="#note134"><b>134)</b></a></sup> A volatile declaration may be used to describe an object corresponding to a memory-mapped
input/output port or an object accessed by an asynchronously interrupting function. Actions on
objects so declared shall not be ''optimized out'' by an implementation or reordered except as
permitted by the rules for evaluating expressions.
- 135) For example, a statement that assigns a value returned by malloc to a single pointer establishes this
+ <sup><a name="note135" href="#note135"><b>135)</b></a></sup> For example, a statement that assigns a value returned by malloc to a single pointer establishes this
association between the allocated object and the pointer.
- 136) Both of these can occur through the use of typedefs.
+ <sup><a name="note136" href="#note136"><b>136)</b></a></sup> Both of these can occur through the use of typedefs.
-[<a name="
#p121" href="p121">page 121</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p121" href="#p121">page 121</a>] (<a href="#Contents">Contents</a>)
13 EXAMPLE 3 The declaration
_Atomic volatile int *p;
whatever function is called at program startup in a freestanding environment).
3 In what follows, a pointer expression E is said to be based on object P if (at some
sequence point in the execution of B prior to the evaluation of E) modifying P to point to
- a copy of the array object into which it formerly pointed would change the value of E.137)
+ a copy of the array object into which it formerly pointed would change the value of E.<sup><a href="#note137"><b>137)</b></a></sup>
Note that ''based'' is defined only for expressions with pointer types.
4 During each execution of B, let L be any lvalue that has &L based on P. If L is used to
access the value of the object X that it designates, and X is also modified (by any means),
program, then it is never accessed using either of the other two.
- 137) In other words, E depends on the value of P itself rather than on the value of an object referenced
+ <sup><a name="note137" href="#note137"><b>137)</b></a></sup> In other words, E depends on the value of P itself rather than on the value of an object referenced
indirectly through P. For example, if identifier p has type (int **restrict), then the pointer
expressions p and p+1 are based on the restricted pointer object designated by p, but the pointer
expressions *p and p[1] are not.
-[<a name="
#p122" href="p122">page 122</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p122" href="#p122">page 122</a>] (<a href="#Contents">Contents</a>)
8 EXAMPLE 2 The function parameter declarations in the following example
void f(int n, int * restrict p, int * restrict q)
}
}
-
-
-
-[<a name="#p123" href="p123">page 123</a>] (<a href="#Contents">Contents</a>)
+[<a name="p123" href="#p123">page 123</a>] (<a href="#Contents">Contents</a>)
12 The one exception allows the value of a restricted pointer to be carried out of the block in which it (or, more
precisely, the ordinary identifier used to designate it) is declared when that block finishes execution. For
}
<a name="6.7.4" href="#6.7.4"><b> 6.7.4 Function specifiers</b></a>
- Syntax
+<b> Syntax</b>
1 function-specifier:
inline
_Noreturn
- Constraints
+<b> Constraints</b>
2 Function specifiers shall be used only in the declaration of an identifier for a function.
3 An inline definition of a function with external linkage shall not contain a definition of a
modifiable object with static or thread storage duration, and shall not contain a reference
to an identifier with internal linkage.
4 In a hosted environment, no function specifier(s) shall appear in a declaration of main.
- Semantics
+<b> Semantics</b>
5 A function specifier may appear more than once; the behavior is the same as if it
appeared only once.
6 A function declared with an inline function specifier is an inline function. Making a *
- function an inline function suggests that calls to the function be as fast as possible.138)
- The extent to which such suggestions are effective is implementation-defined.139)
+ function an inline function suggests that calls to the function be as fast as possible.<sup><a href="#note138"><b>138)</b></a></sup>
+ The extent to which such suggestions are effective is implementation-defined.<sup><a href="#note139"><b>139)</b></a></sup>
- 138) By using, for example, an alternative to the usual function call mechanism, such as ''inline
+ <sup><a name="note138" href="#note138"><b>138)</b></a></sup> By using, for example, an alternative to the usual function call mechanism, such as ''inline
substitution''. Inline substitution is not textual substitution, nor does it create a new function.
Therefore, for example, the expansion of a macro used within the body of the function uses the
definition it had at the point the function body appears, and not where the function is called; and
identifiers refer to the declarations in scope where the body occurs. Likewise, the function has a
single address, regardless of the number of inline definitions that occur in addition to the external
definition.
- 139) For example, an implementation might never perform inline substitution, or might only perform inline
+ <sup><a name="note139" href="#note139"><b>139)</b></a></sup> For example, an implementation might never perform inline substitution, or might only perform inline
substitutions to calls in the scope of an inline declaration.
-[<a name="
#p124" href="p124">page 124</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p124" href="#p124">page 124</a>] (<a href="#Contents">Contents</a>)
7 Any function with internal linkage can be an inline function. For a function with external
linkage, the following restrictions apply: If a function is declared with an inline
and does not forbid an external definition in another translation unit. An inline definition
provides an alternative to an external definition, which a translator may use to implement
any call to the function in the same translation unit. It is unspecified whether a call to the
- function uses the inline definition or the external definition.140)
+ function uses the inline definition or the external definition.<sup><a href="#note140"><b>140)</b></a></sup>
8 A function declared with a _Noreturn function specifier shall not return to its caller.
Recommended practice
9 The implementation should produce a diagnostic message for a function declared with a
extern creates an external definition. The following example shows an entire translation unit.
inline double fahr(double t)
{
- return (<a href="#9.0">9.0</a> * t) / <a href="#5.0">5.0</a> + 32.0;
+ return (9.0 * t) / 5.0 + 32.0;
}
inline double cels(double t)
{
- return (<a href="#5.0">5.0</a> * (t - 32.0)) / <a href="#9.0">9.0</a>;
+ return (5.0 * (t - 32.0)) / 9.0;
}
extern double fahr(double); // creates an external definition
double convert(int is_fahr, double temp)
- 140) Since an inline definition is distinct from the corresponding external definition and from any other
+ <sup><a name="note140" href="#note140"><b>140)</b></a></sup> Since an inline definition is distinct from the corresponding external definition and from any other
corresponding inline definitions in other translation units, all corresponding objects with static storage
duration are also distinct in each of the definitions.
-[<a name="
#p125" href="p125">page 125</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p125" href="#p125">page 125</a>] (<a href="#Contents">Contents</a>)
_Noreturn void f () {
abort(); // ok
Forward references: function definitions (<a href="#6.9.1">6.9.1</a>).
<a name="6.7.5" href="#6.7.5"><b> 6.7.5 Alignment specifier</b></a>
- Syntax
+<b> Syntax</b>
1 alignment-specifier:
_Alignas ( type-name )
_Alignas ( constant-expression )
- Constraints
+<b> Constraints</b>
2 An alignment attribute shall not be specified in a declaration of a typedef, or a bit-field, or
a function, or a parameter, or an object declared with the register storage-class
specifier.
4 The combined effect of all alignment attributes in a declaration shall not specify an
alignment that is less strict than the alignment that would otherwise be required for the
type of the object or member being declared.
- Semantics
+<b> Semantics</b>
5 The first form is equivalent to _Alignas(alignof(type-name)).
6 The alignment requirement of the declared object or member is taken to be the specified
- alignment. An alignment specification of zero has no effect.141) When multiple
+ alignment. An alignment specification of zero has no effect.<sup><a href="#note141"><b>141)</b></a></sup> When multiple
alignment specifiers occur in a declaration, the effective alignment requirement is the
strictest specified alignment.
7 If the definition of an object has an alignment specifier, any other declaration of that
- 141) An alignment specification of zero also does not affect other alignment specifications in the same
+ <sup><a name="note141" href="#note141"><b>141)</b></a></sup> An alignment specification of zero also does not affect other alignment specifications in the same
declaration.
-[<a name="
#p126" href="p126">page 126</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p126" href="#p126">page 126</a>] (<a href="#Contents">Contents</a>)
<a name="6.7.6" href="#6.7.6"><b> 6.7.6 Declarators</b></a>
- Syntax
+<b> Syntax</b>
1 declarator:
pointeropt direct-declarator
direct-declarator:
identifier-list:
identifier
identifier-list , identifier
- Semantics
+<b> Semantics</b>
2 Each declarator declares one identifier, and asserts that when an operand of the same
form as the declarator appears in an expression, it designates a function or object with the
scope, storage duration, and type indicated by the declaration specifiers.
3 A full declarator is a declarator that is not part of another declarator. The end of a full
declarator is a sequence point. If, in the nested sequence of declarators in a full
-[<a name="#p127" href="p127">page 127</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p127" href="#p127">page 127</a>] (<a href="#Contents">Contents</a>)
declarator, there is a declarator specifying a variable length array type, the type specified
by the full declarator is said to be variably modified. Furthermore, any type derived by
directly or via one or more typedefs.
Forward references: array declarators (<a href="#6.7.6.2">6.7.6.2</a>), type definitions (<a href="#6.7.8">6.7.8</a>).
<a name="6.7.6.1" href="#6.7.6.1"><b> 6.7.6.1 Pointer declarators</b></a>
- Semantics
+<b> Semantics</b>
1 If, in the declaration ''T D1'', D1 has the form
* type-qualifier-listopt D
and the type specified for ident in the declaration ''T D'' is ''derived-declarator-type-list
3 EXAMPLE The following pair of declarations demonstrates the difference between a ''variable pointer
to a constant value'' and a ''constant pointer to a variable value''.
-
-
-
-[<a name="#p128" href="p128">page 128</a>] (<a href="#Contents">Contents</a>)
+[<a name="p128" href="#p128">page 128</a>] (<a href="#Contents">Contents</a>)
const int *ptr_to_constant;
int *const constant_ptr;
declares constant_ptr as an object that has type ''const-qualified pointer to int''.
<a name="6.7.6.2" href="#6.7.6.2"><b> 6.7.6.2 Array declarators</b></a>
- Constraints
+<b> Constraints</b>
1 In addition to optional type qualifiers and the keyword static, the [ and ] may delimit
an expression or *. If they delimit an expression (which specifies the size of an array), the
expression shall have an integer type. If the expression is a constant expression, it shall
identifier (as defined in <a href="#6.2.3">6.2.3</a>), have no linkage, and have either block scope or function
prototype scope. If an identifier is declared to be an object with static or thread storage
duration, it shall not have a variable length array type.
- Semantics
+<b> Semantics</b>
3 If, in the declaration ''T D1'', D1 has one of the forms:
D[ type-qualifier-listopt assignment-expressionopt ]
D[ static type-qualifier-listopt assignment-expression ]
D[ type-qualifier-list static assignment-expression ]
D[ type-qualifier-listopt * ]
and the type specified for ident in the declaration ''T D'' is ''derived-declarator-type-list
- T '', then the type specified for ident is ''derived-declarator-type-list array of T ''.142)
+ T '', then the type specified for ident is ''derived-declarator-type-list array of T ''.<sup><a href="#note142"><b>142)</b></a></sup>
(See <a href="#6.7.6.3">6.7.6.3</a> for the meaning of the optional type qualifiers and the keyword static.)
4 If the size is not present, the array type is an incomplete type. If the size is * instead of
being an expression, the array type is a variable length array type of unspecified size,
- which can only be used in declarations or type names with function prototype scope;143)
+ which can only be used in declarations or type names with function prototype scope;<sup><a href="#note143"><b>143)</b></a></sup>
- 142) When several ''array of'' specifications are adjacent, a multidimensional array is declared.
+ <sup><a name="note142" href="#note142"><b>142)</b></a></sup> When several ''array of'' specifications are adjacent, a multidimensional array is declared.
-[<a name="
#p129" href="p129">page 129</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p129" href="#p129">page 129</a>] (<a href="#Contents">Contents</a>)
such arrays are nonetheless complete types. If the size is an integer constant expression
and the element type has a known constant size, the array type is not a variable length
-
143) Thus, * can be used only in function declarations that are not definitions (see <a href="#6.7.6.3">6.7.6.3</a>).
+
<sup><a name="note143" href="#note143"><b>143)</b></a></sup> Thus, * can be used only in function declarations that are not definitions (see <a href="#6.7.6.3">6.7.6.3</a>).
-[<a name="
#p130" href="p130">page 130</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p130" href="#p130">page 130</a>] (<a href="#Contents">Contents</a>)
10 EXAMPLE 4 All declarations of variably modified (VM) types have to be at either block scope or
function prototype scope. Array objects declared with the _Thread_local, static, or extern
Forward references: function declarators (<a href="#6.7.6.3">6.7.6.3</a>), function definitions (<a href="#6.9.1">6.9.1</a>),
initialization (<a href="#6.7.9">6.7.9</a>).
<a name="6.7.6.3" href="#6.7.6.3"><b> 6.7.6.3 Function declarators (including prototypes)</b></a>
- Constraints
+<b> Constraints</b>
1 A function declarator shall not specify a return type that is a function type or an array
type.
2 The only storage-class specifier that shall occur in a parameter declaration is register.
shall be empty.
4 After adjustment, the parameters in a parameter type list in a function declarator that is
part of a definition of that function shall not have incomplete type.
- Semantics
+<b> Semantics</b>
5 If, in the declaration ''T D1'', D1 has the form
-
-
-
-[<a name="#p131" href="p131">page 131</a>] (<a href="#Contents">Contents</a>)
+[<a name="p131" href="#p131">page 131</a>] (<a href="#Contents">Contents</a>)
D( parameter-type-list )
or
8 A declaration of a parameter as ''function returning type'' shall be adjusted to ''pointer to
function returning type'', as in <a href="#6.3.2.1">6.3.2.1</a>.
9 If the list terminates with an ellipsis (, ...), no information about the number or types
- of the parameters after the comma is supplied.144)
+ of the parameters after the comma is supplied.<sup><a href="#note144"><b>144)</b></a></sup>
10 The special case of an unnamed parameter of type void as the only item in the list
specifies that the function has no parameters.
11 If, in a parameter declaration, an identifier can be treated either as a typedef name or as a
list in a function declarator that is part of a definition of that function specifies that the
function has no parameters. The empty list in a function declarator that is not part of a
definition of that function specifies that no information about the number or types of the
- parameters is supplied.145)
+ parameters is supplied.<sup><a href="#note145"><b>145)</b></a></sup>
-
144) The macros defined in the <a href="#7.16"><stdarg.h></a> header (<a href="#7.16">7.16</a>) may be used to access arguments that
+
<sup><a name="note144" href="#note144"><b>144)</b></a></sup> The macros defined in the <a href="#7.16"><stdarg.h></a> header (<a href="#7.16">7.16</a>) may be used to access arguments that
correspond to the ellipsis.
-[<a name="
#p132" href="p132">page 132</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p132" href="#p132">page 132</a>] (<a href="#Contents">Contents</a>)
-15 For two function types to be compatible, both shall specify compatible return types.146)
+15 For two function types to be compatible, both shall specify compatible return types.<sup><a href="#note146"><b>146)</b></a></sup>
Moreover, the parameter type lists, if both are present, shall agree in the number of
parameters and in use of the ellipsis terminator; corresponding parameters shall have
compatible types. If one type has a parameter type list and the other type is specified by a
The pointer returned by fpfi points to a function that has one int parameter and accepts zero or more
-
145) See ''future language directions'' (<a href="#6.11.6">6.11.6</a>).
- 146) If both function types are ''old style'', parameter types are not compared.
+
<sup><a name="note145" href="#note145"><b>145)</b></a></sup> See ''future language directions'' (<a href="#6.11.6">6.11.6</a>).
+ <sup><a name="note146" href="#note146"><b>146)</b></a></sup> If both function types are ''old style'', parameter types are not compared.
-[<a name="
#p133" href="p133">page 133</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p133" href="#p133">page 133</a>] (<a href="#Contents">Contents</a>)
additional arguments of any type.
Forward references: function definitions (<a href="#6.9.1">6.9.1</a>), type names (<a href="#6.7.7">6.7.7</a>).
-
-
-
-[<a name="#p134" href="p134">page 134</a>] (<a href="#Contents">Contents</a>)
+[<a name="p134" href="#p134">page 134</a>] (<a href="#Contents">Contents</a>)
<a name="6.7.7" href="#6.7.7"><b> 6.7.7 Type names</b></a>
- Syntax
+<b> Syntax</b>
1 type-name:
specifier-qualifier-list abstract-declaratoropt
abstract-declarator:
assignment-expression ]
direct-abstract-declaratoropt [ * ]
direct-abstract-declaratoropt ( parameter-type-listopt )
- Semantics
+<b> Semantics</b>
2 In several contexts, it is necessary to specify a type. This is accomplished using a type
name, which is syntactically a declaration for a function or an object of that type that
- omits the identifier.147)
+ omits the identifier.<sup><a href="#note147"><b>147)</b></a></sup>
3 EXAMPLE The constructions
(a) int
(b) int *
- 147) As indicated by the syntax, empty parentheses in a type name are interpreted as ''function with no
+ <sup><a name="note147" href="#note147"><b>147)</b></a></sup> As indicated by the syntax, empty parentheses in a type name are interpreted as ''function with no
parameter specification'', rather than redundant parentheses around the omitted identifier.
-[<a name="
#p135" href="p135">page 135</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p135" href="#p135">page 135</a>] (<a href="#Contents">Contents</a>)
<a name="6.7.8" href="#6.7.8"><b> 6.7.8 Type definitions</b></a>
- Syntax
+<b> Syntax</b>
1 typedef-name:
identifier
- Constraints
+<b> Constraints</b>
2 If a typedef name specifies a variably modified type then it shall have block scope.
- Semantics
+<b> Semantics</b>
3 In a declaration whose storage-class specifier is typedef, each declarator defines an
identifier to be a typedef name that denotes the type specified for the identifier in the way
described in <a href="#6.7.6">6.7.6</a>. Any array size expressions associated with variable length array
type t1 and the type pointed to by tp1 are compatible. Type t1 is also compatible with type struct
s1, but not compatible with the types struct s2, t2, the type pointed to by tp2, or int.
-
-
-
-[<a name="#p136" href="p136">page 136</a>] (<a href="#Contents">Contents</a>)
+[<a name="p136" href="#p136">page 136</a>] (<a href="#Contents">Contents</a>)
6 EXAMPLE 3 The following obscure constructions
typedef signed int t;
a[i-1] = b[i];
}
-
-
-
-[<a name="#p137" href="p137">page 137</a>] (<a href="#Contents">Contents</a>)
+[<a name="p137" href="#p137">page 137</a>] (<a href="#Contents">Contents</a>)
<a name="6.7.9" href="#6.7.9"><b> 6.7.9 Initialization</b></a>
- Syntax
+<b> Syntax</b>
1 initializer:
assignment-expression
{ initializer-list }
designator:
[ constant-expression ]
. identifier
- Constraints
+<b> Constraints</b>
2 No initializer shall attempt to provide a value for an object not contained within the entity
being initialized.
3 The type of the entity to be initialized shall be an array of unknown size or a complete
. identifier
then the current object (defined below) shall have structure or union type and the
identifier shall be the name of a member of that type.
-[<a name="#p138" href="p138">page 138</a>] (<a href="#Contents">Contents</a>)
- Semantics
+[<a name="p138" href="#p138">page 138</a>] (<a href="#Contents">Contents</a>)
+
+<b> Semantics</b>
8 An initializer specifies the initial value stored in an object.
9 Except where explicitly stated otherwise, for the purposes of this subclause unnamed
members of objects of structure and union type do not participate in initialization.
16 Otherwise, the initializer for an object that has aggregate or union type shall be a brace-
enclosed list of initializers for the elements or named members.
-
-[<a name="#p139" href="p139">page 139</a>] (<a href="#Contents">Contents</a>)
+[<a name="p139" href="#p139">page 139</a>] (<a href="#Contents">Contents</a>)
17 Each brace-enclosed initializer list has an associated current object. When no
designations are present, subobjects of the current object are initialized in order according
to the type of the current object: array elements in increasing subscript order, structure
- members in declaration order, and the first named member of a union.148) In contrast, a
+ members in declaration order, and the first named member of a union.<sup><a href="#note148"><b>148)</b></a></sup> In contrast, a
designation causes the following initializer to begin initialization of the subobject
described by the designator. Initialization then continues forward in order, beginning
- with the next subobject after that described by the designator.149)
+ with the next subobject after that described by the designator.<sup><a href="#note149"><b>149)</b></a></sup>
18 Each designator list begins its description with the current object associated with the
closest surrounding brace pair. Each item in the designator list (in order) specifies a
particular member of its current object and changes the current object for the next
- designator (if any) to be that member.150) The current object that results at the end of the
+ designator (if any) to be that member.<sup><a href="#note150"><b>150)</b></a></sup> The current object that results at the end of the
designator list is the subobject to be initialized by the following initializer.
19 The initialization shall occur in initializer list order, each initializer provided for a
- particular subobject overriding any previously listed initializer for the same subobject;151)
+ particular subobject overriding any previously listed initializer for the same subobject;<sup><a href="#note151"><b>151)</b></a></sup>
all subobjects that are not initialized explicitly shall be initialized implicitly the same as
objects that have static storage duration.
20 If the aggregate or union contains elements or members that are aggregates or unions,
- 148) If the initializer list for a subaggregate or contained union does not begin with a left brace, its
+ <sup><a name="note148" href="#note148"><b>148)</b></a></sup> If the initializer list for a subaggregate or contained union does not begin with a left brace, its
subobjects are initialized as usual, but the subaggregate or contained union does not become the
current object: current objects are associated only with brace-enclosed initializer lists.
- 149) After a union member is initialized, the next object is not the next member of the union; instead, it is
+ <sup><a name="note149" href="#note149"><b>149)</b></a></sup> After a union member is initialized, the next object is not the next member of the union; instead, it is
the next subobject of an object containing the union.
- 150) Thus, a designator can only specify a strict subobject of the aggregate or union that is associated with
+ <sup><a name="note150" href="#note150"><b>150)</b></a></sup> Thus, a designator can only specify a strict subobject of the aggregate or union that is associated with
the surrounding brace pair. Note, too, that each separate designator list is independent.
- 151) Any initializer for the subobject which is overridden and so not used to initialize that subobject might
+ <sup><a name="note151" href="#note151"><b>151)</b></a></sup> Any initializer for the subobject which is overridden and so not used to initialize that subobject might
not be evaluated at all.
-[<a name="
#p140" href="p140">page 140</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p140" href="#p140">page 140</a>] (<a href="#Contents">Contents</a>)
22 If an array of unknown size is initialized, its size is determined by the largest indexed
element with an explicit initializer. The array type is completed at the end of its
initializer list.
23 The evaluations of the initialization list expressions are indeterminately sequenced with
respect to one another and thus the order in which any side effects occur is
- unspecified.152)
+ unspecified.<sup><a href="#note152"><b>152)</b></a></sup>
24 EXAMPLE 1 Provided that <a href="#7.3"><complex.h></a> has been #included, the declarations
int i = <a href="#3.5">3.5</a>;
double complex c = 5 + 3 * I;
- define and initialize i with the value 3 and c with the value <a href="#5.0">5.0</a> + i3.0.
+ define and initialize i with the value 3 and c with the value 5.0 + i3.0.
25 EXAMPLE 2 The declaration
int x[] = { 1, 3, 5 };
- 152) In particular, the evaluation order need not be the same as the order of subobject initialization.
+ <sup><a name="note152" href="#note152"><b>152)</b></a></sup> In particular, the evaluation order need not be the same as the order of subobject initialization.
-[<a name="
#p141" href="p141">page 141</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p141" href="#p141">page 141</a>] (<a href="#Contents">Contents</a>)
structures: w[0].a[0] is 1 and w[1].a[0] is 2; all the other elements are zero.
int a[] = { 1, 2 }, b[] = { 3, 4, 5 };
due to the rules for incomplete types.
-[<a name="
#p142" href="p142">page 142</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p142" href="#p142">page 142</a>] (<a href="#Contents">Contents</a>)
32 EXAMPLE 8 The declaration
char s[] = "abc", t[3] = "abc";
Forward references: common definitions <a href="#7.19"><stddef.h></a> (<a href="#7.19">7.19</a>).
-
-
-
-[<a name="#p143" href="p143">page 143</a>] (<a href="#Contents">Contents</a>)
+[<a name="p143" href="#p143">page 143</a>] (<a href="#Contents">Contents</a>)
<a name="6.7.10" href="#6.7.10"><b> 6.7.10 Static assertions</b></a>
- Syntax
+<b> Syntax</b>
1 static_assert-declaration:
_Static_assert ( constant-expression , string-literal ) ;
- Constraints
+<b> Constraints</b>
2 The constant expression shall compare unequal to 0.
- Semantics
+<b> Semantics</b>
3 The constant expression shall be an integer constant expression. If the value of the
constant expression compares unequal to 0, the declaration has no effect. Otherwise, the
constraint is violated and the implementation shall produce a diagnostic message that
character set are not required to appear in the message.
Forward references: diagnostics (<a href="#7.2">7.2</a>).
-
-
-
-[<a name="#p144" href="p144">page 144</a>] (<a href="#Contents">Contents</a>)
+[<a name="p144" href="#p144">page 144</a>] (<a href="#Contents">Contents</a>)
<a name="6.8" href="#6.8"><b> 6.8 Statements and blocks</b></a>
- Syntax
+<b> Syntax</b>
1 statement:
labeled-statement
compound-statement
selection-statement
iteration-statement
jump-statement
- Semantics
+<b> Semantics</b>
2 A statement specifies an action to be performed. Except as indicated, statements are
executed in sequence.
3 A block allows a set of declarations and statements to be grouped into one syntactic unit.
Forward references: expression and null statements (<a href="#6.8.3">6.8.3</a>), selection statements
(<a href="#6.8.4">6.8.4</a>), iteration statements (<a href="#6.8.5">6.8.5</a>), the return statement (<a href="#6.8.6.4">6.8.6.4</a>).
<a name="6.8.1" href="#6.8.1"><b> 6.8.1 Labeled statements</b></a>
- Syntax
+<b> Syntax</b>
1 labeled-statement:
identifier : statement
case constant-expression : statement
default : statement
- Constraints
+<b> Constraints</b>
2 A case or default label shall appear only in a switch statement. Further
constraints on such labels are discussed under the switch statement.
-[<a name="
#p145" href="p145">page 145</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p145" href="#p145">page 145</a>] (<a href="#Contents">Contents</a>)
3 Label names shall be unique within a function.
- Semantics
+<b> Semantics</b>
4 Any statement may be preceded by a prefix that declares an identifier as a label name.
Labels in themselves do not alter the flow of control, which continues unimpeded across
them.
Forward references: the goto statement (<a href="#6.8.6.1">6.8.6.1</a>), the switch statement (<a href="#6.8.4.2">6.8.4.2</a>).
<a name="6.8.2" href="#6.8.2"><b> 6.8.2 Compound statement</b></a>
- Syntax
+<b> Syntax</b>
1 compound-statement:
{ block-item-listopt }
block-item-list:
block-item:
declaration
statement
- Semantics
+<b> Semantics</b>
2 A compound statement is a block.
<a name="6.8.3" href="#6.8.3"><b> 6.8.3 Expression and null statements</b></a>
- Syntax
+<b> Syntax</b>
1 expression-statement:
expressionopt ;
- Semantics
+<b> Semantics</b>
2 The expression in an expression statement is evaluated as a void expression for its side
- effects.153)
+ effects.<sup><a href="#note153"><b>153)</b></a></sup>
3 A null statement (consisting of just a semicolon) performs no operations.
4 EXAMPLE 1 If a function call is evaluated as an expression statement for its side effects only, the
discarding of its value may be made explicit by converting the expression to a void expression by means of
- 153) Such as assignments, and function calls which have side effects.
+ <sup><a name="note153" href="#note153"><b>153)</b></a></sup> Such as assignments, and function calls which have side effects.
-[<a name="
#p146" href="p146">page 146</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p146" href="#p146">page 146</a>] (<a href="#Contents">Contents</a>)
5 EXAMPLE 2 In the program fragment
char *s;
Forward references: iteration statements (<a href="#6.8.5">6.8.5</a>).
<a name="6.8.4" href="#6.8.4"><b> 6.8.4 Selection statements</b></a>
- Syntax
+<b> Syntax</b>
1 selection-statement:
if ( expression ) statement
if ( expression ) statement else statement
switch ( expression ) statement
- Semantics
+<b> Semantics</b>
2 A selection statement selects among a set of statements depending on the value of a
controlling expression.
3 A selection statement is a block whose scope is a strict subset of the scope of its
enclosing block. Each associated substatement is also a block whose scope is a strict
subset of the scope of the selection statement.
<a name="6.8.4.1" href="#6.8.4.1"><b> 6.8.4.1 The if statement</b></a>
- Constraints
+<b> Constraints</b>
1 The controlling expression of an if statement shall have scalar type.
- Semantics
+<b> Semantics</b>
2 In both forms, the first substatement is executed if the expression compares unequal to 0.
In the else form, the second substatement is executed if the expression compares equal
-
-[<a name="#p147" href="p147">page 147</a>] (<a href="#Contents">Contents</a>)
+[<a name="p147" href="#p147">page 147</a>] (<a href="#Contents">Contents</a>)
to 0. If the first substatement is reached via a label, the second substatement is not
executed.
3 An else is associated with the lexically nearest preceding if that is allowed by the
syntax.
<a name="6.8.4.2" href="#6.8.4.2"><b> 6.8.4.2 The switch statement</b></a>
- Constraints
+<b> Constraints</b>
1 The controlling expression of a switch statement shall have integer type.
2 If a switch statement has an associated case or default label within the scope of an
identifier with a variably modified type, the entire switch statement shall be within the
- scope of that identifier.154)
+ scope of that identifier.<sup><a href="#note154"><b>154)</b></a></sup>
3 The expression of each case label shall be an integer constant expression and no two of
the case constant expressions in the same switch statement shall have the same value
after conversion. There may be at most one default label in a switch statement.
(Any enclosed switch statement may have a default label or case constant
expressions with values that duplicate case constant expressions in the enclosing
switch statement.)
- Semantics
+<b> Semantics</b>
4 A switch statement causes control to jump to, into, or past the statement that is the
switch body, depending on the value of a controlling expression, and on the presence of a
default label and the values of any case labels on or in the switch body. A case or
- 154) That is, the declaration either precedes the switch statement, or it follows the last case or
+ <sup><a name="note154" href="#note154"><b>154)</b></a></sup> That is, the declaration either precedes the switch statement, or it follows the last case or
default label associated with the switch that is in the block containing the declaration.
-[<a name="
#p148" href="p148">page 148</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p148" href="#p148">page 148</a>] (<a href="#Contents">Contents</a>)
7 EXAMPLE In the artificial program fragment
switch (expr)
access an indeterminate value. Similarly, the call to the function f cannot be reached.
<a name="6.8.5" href="#6.8.5"><b> 6.8.5 Iteration statements</b></a>
- Syntax
+<b> Syntax</b>
1 iteration-statement:
while ( expression ) statement
do statement while ( expression ) ;
for ( expressionopt ; expressionopt ; expressionopt ) statement
for ( declaration expressionopt ; expressionopt ) statement
- Constraints
+<b> Constraints</b>
2 The controlling expression of an iteration statement shall have scalar type.
3 The declaration part of a for statement shall only declare identifiers for objects having
storage class auto or register.
- Semantics
+<b> Semantics</b>
4 An iteration statement causes a statement called the loop body to be executed repeatedly
until the controlling expression compares equal to 0. The repetition occurs regardless of
- whether the loop body is entered from the iteration statement or by a jump.155)
+ whether the loop body is entered from the iteration statement or by a jump.<sup><a href="#note155"><b>155)</b></a></sup>
5 An iteration statement is a block whose scope is a strict subset of the scope of its
enclosing block. The loop body is also a block whose scope is a strict subset of the scope
of the iteration statement.
-6 An iteration statement whose controlling expression is not a constant expression,156) that
+6 An iteration statement whose controlling expression is not a constant expression,<sup><a href="#note156"><b>156)</b></a></sup> that
performs no input/output operations, does not access volatile objects, and performs no
synchronization or atomic operations in its body, controlling expression, or (in the case of
- 155) Code jumped over is not executed. In particular, the controlling expression of a for or while
+ <sup><a name="note155" href="#note155"><b>155)</b></a></sup> Code jumped over is not executed. In particular, the controlling expression of a for or while
statement is not evaluated before entering the loop body, nor is clause-1 of a for statement.
- 156) An omitted controlling expression is replaced by a nonzero constant, which is a constant expression.
+ <sup><a name="note156" href="#note156"><b>156)</b></a></sup> An omitted controlling expression is replaced by a nonzero constant, which is a constant expression.
-[<a name="
#p149" href="p149">page 149</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p149" href="#p149">page 149</a>] (<a href="#Contents">Contents</a>)
a for statement) its expression-3, may be assumed by the implementation to
- terminate.157)
+ terminate.<sup><a href="#note157"><b>157)</b></a></sup>
<a name="6.8.5.1" href="#6.8.5.1"><b> 6.8.5.1 The while statement</b></a>
1 The evaluation of the controlling expression takes place before each execution of the loop
body.
declaration, the scope of any identifiers it declares is the remainder of the declaration and
the entire loop, including the other two expressions; it is reached in the order of execution
before the first evaluation of the controlling expression. If clause-1 is an expression, it is
- evaluated as a void expression before the first evaluation of the controlling expression.158)
+ evaluated as a void expression before the first evaluation of the controlling expression.<sup><a href="#note158"><b>158)</b></a></sup>
2 Both clause-1 and expression-3 can be omitted. An omitted expression-2 is replaced by a
nonzero constant.
<a name="6.8.6" href="#6.8.6"><b> 6.8.6 Jump statements</b></a>
- Syntax
+<b> Syntax</b>
1 jump-statement:
goto identifier ;
continue ;
- 157) This is intended to allow compiler transformations such as removal of empty loops even when
+ <sup><a name="note157" href="#note157"><b>157)</b></a></sup> This is intended to allow compiler transformations such as removal of empty loops even when
termination cannot be proven.
- 158) Thus, clause-1 specifies initialization for the loop, possibly declaring one or more variables for use in
+ <sup><a name="note158" href="#note158"><b>158)</b></a></sup> Thus, clause-1 specifies initialization for the loop, possibly declaring one or more variables for use in
the loop; the controlling expression, expression-2, specifies an evaluation made before each iteration,
such that execution of the loop continues until the expression compares equal to 0; and expression-3
specifies an operation (such as incrementing) that is performed after each iteration.
-[<a name="
#p150" href="p150">page 150</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p150" href="#p150">page 150</a>] (<a href="#Contents">Contents</a>)
- Semantics
+<b> Semantics</b>
2 A jump statement causes an unconditional jump to another place.
<a name="6.8.6.1" href="#6.8.6.1"><b> 6.8.6.1 The goto statement</b></a>
- Constraints
+<b> Constraints</b>
1 The identifier in a goto statement shall name a label located somewhere in the enclosing
function. A goto statement shall not jump from outside the scope of an identifier having
a variably modified type to inside the scope of that identifier.
- Semantics
+<b> Semantics</b>
2 A goto statement causes an unconditional jump to the statement prefixed by the named
label in the enclosing function.
3 EXAMPLE 1 It is sometimes convenient to jump into the middle of a complicated set of statements. The
/* ... */
}
-
-
-
-[<a name="#p151" href="p151">page 151</a>] (<a href="#Contents">Contents</a>)
+[<a name="p151" href="#p151">page 151</a>] (<a href="#Contents">Contents</a>)
4 EXAMPLE 2 A goto statement is not allowed to jump past any declarations of objects with variably
modified types. A jump within the scope, however, is permitted.
goto lab4; // invalid: going INTO scope of VLA.
<a name="6.8.6.2" href="#6.8.6.2"><b> 6.8.6.2 The continue statement</b></a>
- Constraints
+<b> Constraints</b>
1 A continue statement shall appear only in or as a loop body.
- Semantics
+<b> Semantics</b>
2 A continue statement causes a jump to the loop-continuation portion of the smallest
enclosing iteration statement; that is, to the end of the loop body. More precisely, in each
of the statements
contin: ; contin: ; contin: ;
} } while (/* ... */); }
unless the continue statement shown is in an enclosed iteration statement (in which
- case it is interpreted within that statement), it is equivalent to goto contin;.159)
+ case it is interpreted within that statement), it is equivalent to goto contin;.<sup><a href="#note159"><b>159)</b></a></sup>
<a name="6.8.6.3" href="#6.8.6.3"><b> 6.8.6.3 The break statement</b></a>
- Constraints
+<b> Constraints</b>
1 A break statement shall appear only in or as a switch body or loop body.
- Semantics
+<b> Semantics</b>
2 A break statement terminates execution of the smallest enclosing switch or iteration
statement.
- 159) Following the contin: label is a null statement.
+ <sup><a name="note159" href="#note159"><b>159)</b></a></sup> Following the contin: label is a null statement.
-[<a name="
#p152" href="p152">page 152</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p152" href="#p152">page 152</a>] (<a href="#Contents">Contents</a>)
<a name="6.8.6.4" href="#6.8.6.4"><b> 6.8.6.4 The return statement</b></a>
- Constraints
+<b> Constraints</b>
1 A return statement with an expression shall not appear in a function whose return type
is void. A return statement without an expression shall only appear in a function
whose return type is void.
- Semantics
+<b> Semantics</b>
2 A return statement terminates execution of the current function and returns control to
its caller. A function may have any number of return statements.
3 If a return statement with an expression is executed, the value of the expression is
returned to the caller as the value of the function call expression. If the expression has a
type different from the return type of the function in which it appears, the value is
- converted as if by assignment to an object having the return type of the function.160)
+ converted as if by assignment to an object having the return type of the function.<sup><a href="#note160"><b>160)</b></a></sup>
4 EXAMPLE In:
struct s { double i; } f(void);
union {
-
160) The return statement is not an assignment. The overlap restriction of subclause <a href="#6.5.16.1">6.5.16.1</a> does not
+
<sup><a name="note160" href="#note160"><b>160)</b></a></sup> The return statement is not an assignment. The overlap restriction of subclause <a href="#6.5.16.1">6.5.16.1</a> does not
apply to the case of function return. The representation of floating-point values may have wider range
or precision than implied by the type; a cast may be used to remove this extra range and precision.
-[<a name="
#p153" href="p153">page 153</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p153" href="#p153">page 153</a>] (<a href="#Contents">Contents</a>)
<a name="6.9" href="#6.9"><b> 6.9 External definitions</b></a>
- Syntax
+<b> Syntax</b>
1 translation-unit:
external-declaration
translation-unit external-declaration
external-declaration:
function-definition
declaration
- Constraints
+<b> Constraints</b>
2 The storage-class specifiers auto and register shall not appear in the declaration
specifiers in an external declaration.
3 There shall be no more than one external definition for each identifier declared with
linkage is used in an expression (other than as a part of the operand of a sizeof
operator whose result is an integer constant), there shall be exactly one external definition
for the identifier in the translation unit.
- Semantics
+<b> Semantics</b>
4 As discussed in <a href="#5.1.1.1">5.1.1.1</a>, the unit of program text after preprocessing is a translation unit,
which consists of a sequence of external declarations. These are described as ''external''
because they appear outside any function (and hence have file scope). As discussed in
linkage is used in an expression (other than as part of the operand of a sizeof operator
whose result is an integer constant), somewhere in the entire program there shall be
exactly one external definition for the identifier; otherwise, there shall be no more than
- one.161)
+ one.<sup><a href="#note161"><b>161)</b></a></sup>
- 161) Thus, if an identifier declared with external linkage is not used in an expression, there need be no
+ <sup><a name="note161" href="#note161"><b>161)</b></a></sup> Thus, if an identifier declared with external linkage is not used in an expression, there need be no
external definition for it.
-[<a name="
#p154" href="p154">page 154</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p154" href="#p154">page 154</a>] (<a href="#Contents">Contents</a>)
<a name="6.9.1" href="#6.9.1"><b> 6.9.1 Function definitions</b></a>
- Syntax
+<b> Syntax</b>
1 function-definition:
declaration-specifiers declarator declaration-listopt compound-statement
declaration-list:
declaration
declaration-list declaration
- Constraints
+<b> Constraints</b>
2 The identifier declared in a function definition (which is the name of the function) shall
- have a function type, as specified by the declarator portion of the function definition.162)
+ have a function type, as specified by the declarator portion of the function definition.<sup><a href="#note162"><b>162)</b></a></sup>
3 The return type of a function shall be void or a complete object type other than array
type.
4 The storage-class specifier, if any, in the declaration specifiers shall be either extern or
- 162) The intent is that the type category in a function definition cannot be inherited from a typedef:
+ <sup><a name="note162" href="#note162"><b>162)</b></a></sup> The intent is that the type category in a function definition cannot be inherited from a typedef:
typedef int F(void); // type F is ''function with no parameters
// returning int''
F f, g; // f and g both have type compatible with F
int (*fp)(void); // fp points to a function that has type F
F *Fp; // Fp points to a function that has type F
+[<a name="p155" href="#p155">page 155</a>] (<a href="#Contents">Contents</a>)
-[<a name="#p155" href="p155">page 155</a>] (<a href="#Contents">Contents</a>)
-
- Semantics
+<b> Semantics</b>
7 The declarator in a function definition specifies the name of the function being defined
and the identifiers of its parameters. If the declarator includes a parameter type list, the
list also specifies the types of all the parameters; such a declarator also serves as a
function prototype for later calls to the same function in the same translation unit. If the
- declarator includes an identifier list,163) the types of the parameters shall be declared in a
+ declarator includes an identifier list,<sup><a href="#note163"><b>163)</b></a></sup> the types of the parameters shall be declared in a
following declaration list. In either case, the type of each parameter is adjusted as
described in <a href="#6.7.6.3">6.7.6.3</a> for a parameter type list; the resulting type shall be a complete object
type.
8 If a function that accepts a variable number of arguments is defined without a parameter
type list that ends with the ellipsis notation, the behavior is undefined.
-9 Each parameter has automatic storage duration; its identifier is an lvalue.164) The layout
+9 Each parameter has automatic storage duration; its identifier is an lvalue.<sup><a href="#note164"><b>164)</b></a></sup> The layout
of the storage for parameters is unspecified.
10 On entry to the function, the size expressions of each variably modified parameter are
evaluated and the value of each argument expression is converted to the type of the
-
163) See ''future language directions'' (<a href="#6.11.7">6.11.7</a>).
- 164) A parameter identifier cannot be redeclared in the function body except in an enclosed block.
+
<sup><a name="note163" href="#note163"><b>163)</b></a></sup> See ''future language directions'' (<a href="#6.11.7">6.11.7</a>).
+ <sup><a name="note164" href="#note164"><b>164)</b></a></sup> A parameter identifier cannot be redeclared in the function body except in an enclosed block.
-[<a name="
#p156" href="p156">page 156</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p156" href="#p156">page 156</a>] (<a href="#Contents">Contents</a>)
extern int max(a, b)
int a, b;
}
<a name="6.9.2" href="#6.9.2"><b> 6.9.2 External object definitions</b></a>
- Semantics
+<b> Semantics</b>
1 If the declaration of an identifier for an object has file scope and an initializer, the
declaration is an external definition for the identifier.
2 A declaration of an identifier for an object that has file scope without an initializer, and
3 If the declaration of an identifier for an object is a tentative definition and has internal
linkage, the declared type shall not be an incomplete type.
-
-
-
-[<a name="#p157" href="p157">page 157</a>] (<a href="#Contents">Contents</a>)
+[<a name="p157" href="#p157">page 157</a>] (<a href="#Contents">Contents</a>)
4 EXAMPLE 1
int i1 = 1; // definition, external linkage
the array i still has incomplete type, the implicit initializer causes it to have one element, which is set to
zero on program startup.
-
-
-
-[<a name="#p158" href="p158">page 158</a>] (<a href="#Contents">Contents</a>)
+[<a name="p158" href="#p158">page 158</a>] (<a href="#Contents">Contents</a>)
<a name="6.10" href="#6.10"><b> 6.10 Preprocessing directives</b></a>
- Syntax
+<b> Syntax</b>
1 preprocessing-file:
groupopt
group:
endif-line:
# endif new-line
-
-
-
-[<a name="#p159" href="p159">page 159</a>] (<a href="#Contents">Contents</a>)
+[<a name="p159" href="#p159">page 159</a>] (<a href="#Contents">Contents</a>)
control-line:
# include pp-tokens new-line
pp-tokens preprocessing-token
new-line:
the new-line character
- Description
+<b> Description</b>
2 A preprocessing directive consists of a sequence of preprocessing tokens that satisfies the
following constraints: The first token in the sequence is a # preprocessing token that (at
the start of translation phase 4) is either the first character in the source file (optionally
after white space containing no new-line characters) or that follows white space
containing at least one new-line character. The last token in the sequence is the first new-
- line character that follows the first token in the sequence.165) A new-line character ends
+ line character that follows the first token in the sequence.<sup><a href="#note165"><b>165)</b></a></sup> A new-line character ends
the preprocessing directive even if it occurs within what would otherwise be an
- 165) Thus, preprocessing directives are commonly called ''lines''. These ''lines'' have no other syntactic
+ <sup><a name="note165" href="#note165"><b>165)</b></a></sup> Thus, preprocessing directives are commonly called ''lines''. These ''lines'' have no other syntactic
significance, as all white space is equivalent except in certain situations during preprocessing (see the
# character string literal creation operator in <a href="#6.10.3.2">6.10.3.2</a>, for example).
-[<a name="
#p160" href="p160">page 160</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p160" href="#p160">page 160</a>] (<a href="#Contents">Contents</a>)
invocation of a function-like macro.
3 A text line shall not begin with a # preprocessing token. A non-directive shall not begin
4 When in a group that is skipped (<a href="#6.10.1">6.10.1</a>), the directive syntax is relaxed to allow any
sequence of preprocessing tokens to occur between the directive name and the following
new-line character.
- Constraints
+<b> Constraints</b>
5 The only white-space characters that shall appear between preprocessing tokens within a
preprocessing directive (from just after the introducing # preprocessing token through
just before the terminating new-line character) are space and horizontal-tab (including
spaces that have replaced comments or possibly other white-space characters in
translation phase 3).
- Semantics
+<b> Semantics</b>
6 The implementation can process and skip sections of source files conditionally, include
other source files, and replace macros. These capabilities are called preprocessing,
because conceptually they occur before translation of the resulting translation unit.
replaced.
<a name="6.10.1" href="#6.10.1"><b> 6.10.1 Conditional inclusion</b></a>
- Constraints
+<b> Constraints</b>
1 The expression that controls conditional inclusion shall be an integer constant expression
except that: identifiers (including those lexically identical to keywords) are interpreted as *
- described below;166) and it may contain unary operator expressions of the form
+ described below;<sup><a href="#note166"><b>166)</b></a></sup> and it may contain unary operator expressions of the form
defined identifier
or
defined ( identifier )
which evaluate to 1 if the identifier is currently defined as a macro name (that is, if it is
- 166) Because the controlling constant expression is evaluated during translation phase 4, all identifiers
+ <sup><a name="note166" href="#note166"><b>166)</b></a></sup> Because the controlling constant expression is evaluated during translation phase 4, all identifiers
either are or are not macro names -- there simply are no keywords, enumeration constants, etc.
-[<a name="
#p161" href="p161">page 161</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p161" href="#p161">page 161</a>] (<a href="#Contents">Contents</a>)
predefined or if it has been the subject of a #define preprocessing directive without an
intervening #undef directive with the same subject identifier), 0 if it is not.
2 Each preprocessing token that remains (in the list of preprocessing tokens that will
become the controlling expression) after all macro replacements have occurred shall be in
the lexical form of a token (<a href="#6.4">6.4</a>).
- Semantics
+<b> Semantics</b>
3 Preprocessing directives of the forms
# if constant-expression new-line groupopt
# elif constant-expression new-line groupopt
expression which is evaluated according to the rules of <a href="#6.6">6.6</a>. For the purposes of this
token conversion and evaluation, all signed integer types and all unsigned integer types
act as if they have the same representation as, respectively, the types intmax_t and
- uintmax_t defined in the header <a href="#7.20"><stdint.h></a>.167) This includes interpreting
+ uintmax_t defined in the header <a href="#7.20"><stdint.h></a>.<sup><a href="#note167"><b>167)</b></a></sup> This includes interpreting
character constants, which may involve converting escape sequences into execution
character set members. Whether the numeric value for these character constants matches
the value obtained when an identical character constant occurs in an expression (other
- than within a #if or #elif directive) is implementation-defined.168) Also, whether a
+ than within a #if or #elif directive) is implementation-defined.<sup><a href="#note168"><b>168)</b></a></sup> Also, whether a
single-character character constant may have a negative value is implementation-defined.
- 167) Thus, on an implementation where INT_MAX is 0x7FFF and UINT_MAX is 0xFFFF, the constant
+ <sup><a name="note167" href="#note167"><b>167)</b></a></sup> Thus, on an implementation where INT_MAX is 0x7FFF and UINT_MAX is 0xFFFF, the constant
0x8000 is signed and positive within a #if expression even though it would be unsigned in
translation phase 7.
- 168) Thus, the constant expression in the following #if directive and if statement is not guaranteed to
+ <sup><a name="note168" href="#note168"><b>168)</b></a></sup> Thus, the constant expression in the following #if directive and if statement is not guaranteed to
evaluate to the same value in these two contexts.
#if 'z' - 'a' == 25
if ('z' - 'a' == 25)
-
-[<a name="#p162" href="p162">page 162</a>] (<a href="#Contents">Contents</a>)
+[<a name="p162" href="#p162">page 162</a>] (<a href="#Contents">Contents</a>)
5 Preprocessing directives of the forms
# ifdef identifier new-line groupopt
group. Only the first group whose control condition evaluates to true (nonzero) is
processed. If none of the conditions evaluates to true, and there is a #else directive, the
group controlled by the #else is processed; lacking a #else directive, all the groups
- until the #endif are skipped.169)
+ until the #endif are skipped.<sup><a href="#note169"><b>169)</b></a></sup>
Forward references: macro replacement (<a href="#6.10.3">6.10.3</a>), source file inclusion (<a href="#6.10.2">6.10.2</a>), largest
integer types (<a href="#7.20.1.5">7.20.1.5</a>).
<a name="6.10.2" href="#6.10.2"><b> 6.10.2 Source file inclusion</b></a>
- Constraints
+<b> Constraints</b>
1 A #include directive shall identify a header or source file that can be processed by the
implementation.
- Semantics
+<b> Semantics</b>
2 A preprocessing directive of the form
# include <h-char-sequence> new-line
searches a sequence of implementation-defined places for a header identified uniquely by
by the specified sequence between the " delimiters. The named source file is searched
- 169) As indicated by the syntax, a preprocessing token shall not follow a #else or #endif directive
+ <sup><a name="note169" href="#note169"><b>169)</b></a></sup> As indicated by the syntax, a preprocessing token shall not follow a #else or #endif directive
before the terminating new-line character. However, comments may appear anywhere in a source file,
including within a preprocessing directive.
-[<a name="
#p163" href="p163">page 163</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p163" href="#p163">page 163</a>] (<a href="#Contents">Contents</a>)
for in an implementation-defined manner. If this search is not supported, or if the search
fails, the directive is reprocessed as if it read
tokens after include in the directive are processed just as in normal text. (Each
identifier currently defined as a macro name is replaced by its replacement list of
preprocessing tokens.) The directive resulting after all replacements shall match one of
- the two previous forms.170) The method by which a sequence of preprocessing tokens
+ the two previous forms.<sup><a href="#note170"><b>170)</b></a></sup> The method by which a sequence of preprocessing tokens
between a < and a > preprocessing token pair or a pair of " characters is combined into a
single header name preprocessing token is implementation-defined.
5 The implementation shall provide unique mappings for sequences consisting of one or
- 170) Note that adjacent string literals are not concatenated into a single string literal (see the translation
+ <sup><a name="note170" href="#note170"><b>170)</b></a></sup> Note that adjacent string literals are not concatenated into a single string literal (see the translation
phases in <a href="#5.1.1.2">5.1.1.2</a>); thus, an expansion that results in two string literals is an invalid directive.
-[<a name="
#p164" href="p164">page 164</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p164" href="#p164">page 164</a>] (<a href="#Contents">Contents</a>)
8 EXAMPLE 2 This illustrates macro-replaced #include directives:
#if VERSION == 1
Forward references: macro replacement (<a href="#6.10.3">6.10.3</a>).
<a name="6.10.3" href="#6.10.3"><b> 6.10.3 Macro replacement</b></a>
- Constraints
+<b> Constraints</b>
1 Two replacement lists are identical if and only if the preprocessing tokens in both have
the same number, ordering, spelling, and white-space separation, where all white-space
separations are considered identical.
macro that uses the ellipsis notation in the parameters.
6 A parameter identifier in a function-like macro shall be uniquely declared within its
scope.
- Semantics
+<b> Semantics</b>
7 The identifier immediately following the define is called the macro name. There is one
name space for macro names. Any white-space characters preceding or following the
replacement list of preprocessing tokens are not considered part of the replacement list
-[<a name="
#p165" href="p165">page 165</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p165" href="#p165">page 165</a>] (<a href="#Contents">Contents</a>)
for either form of macro.
8 If a # preprocessing token, followed by an identifier, occurs lexically at the point at which
a preprocessing directive could begin, the identifier is not subject to macro replacement.
9 A preprocessing directive of the form
# define identifier replacement-list new-line
- defines an object-like macro that causes each subsequent instance of the macro name171)
+ defines an object-like macro that causes each subsequent instance of the macro name<sup><a href="#note171"><b>171)</b></a></sup>
to be replaced by the replacement list of preprocessing tokens that constitute the
remainder of the directive. The replacement list is then rescanned for more macro names
as specified below.
the list are separated by comma preprocessing tokens, but comma preprocessing tokens
between matching inner parentheses do not separate arguments. If there are sequences of
preprocessing tokens within the list of arguments that would otherwise act as
- preprocessing directives,172) the behavior is undefined.
+ preprocessing directives,<sup><a href="#note172"><b>172)</b></a></sup> the behavior is undefined.
12 If there is a ... in the identifier-list in the macro definition, then the trailing arguments,
including any separating comma preprocessing tokens, are merged to form a single item:
- 171) Since, by macro-replacement time, all character constants and string literals are preprocessing tokens,
+ <sup><a name="note171" href="#note171"><b>171)</b></a></sup> Since, by macro-replacement time, all character constants and string literals are preprocessing tokens,
not sequences possibly containing identifier-like subsequences (see <a href="#5.1.1.2">5.1.1.2</a>, translation phases), they
are never scanned for macro names or parameters.
- 172) Despite the name, a non-directive is a preprocessing directive.
+ <sup><a name="note172" href="#note172"><b>172)</b></a></sup> Despite the name, a non-directive is a preprocessing directive.
-[<a name="
#p166" href="p166">page 166</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p166" href="#p166">page 166</a>] (<a href="#Contents">Contents</a>)
the variable arguments. The number of arguments so combined is such that, following
merger, the number of arguments is one more than the number of parameters in the macro
were a parameter, and the variable arguments shall form the preprocessing tokens used to
replace it.
<a name="6.10.3.2" href="#6.10.3.2"><b> 6.10.3.2 The # operator</b></a>
- Constraints
+<b> Constraints</b>
1 Each # preprocessing token in the replacement list for a function-like macro shall be
followed by a parameter as the next preprocessing token in the replacement list.
- Semantics
+<b> Semantics</b>
2 If, in the replacement list, a parameter is immediately preceded by a # preprocessing
token, both are replaced by a single character string literal preprocessing token that
contains the spelling of the preprocessing token sequence for the corresponding
string literal corresponding to an empty argument is "". The order of evaluation of # and
## operators is unspecified.
-
-
-
-[<a name="#p167" href="p167">page 167</a>] (<a href="#Contents">Contents</a>)
+[<a name="p167" href="#p167">page 167</a>] (<a href="#Contents">Contents</a>)
<a name="6.10.3.3" href="#6.10.3.3"><b> 6.10.3.3 The ## operator</b></a>
- Constraints
+<b> Constraints</b>
1 A ## preprocessing token shall not occur at the beginning or at the end of a replacement
list for either form of macro definition.
- Semantics
+<b> Semantics</b>
2 If, in the replacement list of a function-like macro, a parameter is immediately preceded
or followed by a ## preprocessing token, the parameter is replaced by the corresponding
argument's preprocessing token sequence; however, if an argument consists of no
preprocessing tokens, the parameter is replaced by a placemarker preprocessing token
- instead.173)
+ instead.<sup><a href="#note173"><b>173)</b></a></sup>
3 For both object-like and function-like macro invocations, before the replacement list is
reexamined for more macro names to replace, each instance of a ## preprocessing token
in the replacement list (not from an argument) is deleted and the preceding preprocessing
this new token is not the ## operator.
- 173) Placemarker preprocessing tokens do not appear in the syntax because they are temporary entities that
+ <sup><a name="note173" href="#note173"><b>173)</b></a></sup> Placemarker preprocessing tokens do not appear in the syntax because they are temporary entities that
exist only within translation phase 4.
-[<a name="
#p168" href="p168">page 168</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p168" href="#p168">page 168</a>] (<a href="#Contents">Contents</a>)
<a name="6.10.3.4" href="#6.10.3.4"><b> 6.10.3.4 Rescanning and further replacement</b></a>
1 After all parameters in the replacement list have been substituted and # and ##
#define max(a, b) ((a) > (b) ? (a) : (b))
The parentheses ensure that the arguments and the resulting expression are bound properly.
-
-
-
-[<a name="#p169" href="p169">page 169</a>] (<a href="#Contents">Contents</a>)
+[<a name="p169" href="#p169">page 169</a>] (<a href="#Contents">Contents</a>)
5 EXAMPLE 3 To illustrate the rules for redefinition and reexamination, the sequence
#define x 3
xglue(HIGH, LOW)
results in
-
-
-
-[<a name="#p170" href="p170">page 170</a>] (<a href="#Contents">Contents</a>)
+[<a name="p170" href="#p170">page 170</a>] (<a href="#Contents">Contents</a>)
printf("x" "1" "= %d, x" "2" "= %s", x1, x2);
fputs(
showlist(The first, second, and third items.);
report(x>y, "x is %d but y is %d", x, y);
-
-[<a name="#p171" href="p171">page 171</a>] (<a href="#Contents">Contents</a>)
+[<a name="p171" href="#p171">page 171</a>] (<a href="#Contents">Contents</a>)
results in
fprintf(stderr, "Flag" );
printf("x is %d but y is %d", x, y));
<a name="6.10.4" href="#6.10.4"><b> 6.10.4 Line control</b></a>
- Constraints
+<b> Constraints</b>
1 The string literal of a #line directive, if present, shall be a character string literal.
- Semantics
+<b> Semantics</b>
2 The line number of the current source line is one greater than the number of new-line
characters read or introduced in translation phase 1 (<a href="#5.1.1.2">5.1.1.2</a>) while processing the source
file to the current token.
tokens). The directive resulting after all replacements shall match one of the two
previous forms and is then processed as appropriate.
-
-
-
-[<a name="#p172" href="p172">page 172</a>] (<a href="#Contents">Contents</a>)
+[<a name="p172" href="#p172">page 172</a>] (<a href="#Contents">Contents</a>)
<a name="6.10.5" href="#6.10.5"><b> 6.10.5 Error directive</b></a>
- Semantics
+<b> Semantics</b>
1 A preprocessing directive of the form
# error pp-tokensopt new-line
causes the implementation to produce a diagnostic message that includes the specified
sequence of preprocessing tokens.
<a name="6.10.6" href="#6.10.6"><b> 6.10.6 Pragma directive</b></a>
- Semantics
+<b> Semantics</b>
1 A preprocessing directive of the form
# pragma pp-tokensopt new-line
where the preprocessing token STDC does not immediately follow pragma in the
- directive (prior to any macro replacement)174) causes the implementation to behave in an
+ directive (prior to any macro replacement)<sup><a href="#note174"><b>174)</b></a></sup> causes the implementation to behave in an
implementation-defined manner. The behavior might cause translation to fail or cause the
translator or the resulting program to behave in a non-conforming manner. Any such
pragma that is not recognized by the implementation is ignored.
2 If the preprocessing token STDC does immediately follow pragma in the directive (prior
to any macro replacement), then no macro replacement is performed on the directive, and
- the directive shall have one of the following forms175) whose meanings are described
+ the directive shall have one of the following forms<sup><a href="#note175"><b>175)</b></a></sup> whose meanings are described
elsewhere:
#pragma STDC FP_CONTRACT on-off-switch
#pragma STDC FENV_ACCESS on-off-switch
- 174) An implementation is not required to perform macro replacement in pragmas, but it is permitted
+ <sup><a name="note174" href="#note174"><b>174)</b></a></sup> An implementation is not required to perform macro replacement in pragmas, but it is permitted
except for in standard pragmas (where STDC immediately follows pragma). If the result of macro
replacement in a non-standard pragma has the same form as a standard pragma, the behavior is still
implementation-defined; an implementation is permitted to behave as if it were the standard pragma,
but is not required to.
-
175) See ''future language directions'' (<a href="#6.11.8">6.11.8</a>).
+
<sup><a name="note175" href="#note175"><b>175)</b></a></sup> See ''future language directions'' (<a href="#6.11.8">6.11.8</a>).
-[<a name="
#p173" href="p173">page 173</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p173" href="#p173">page 173</a>] (<a href="#Contents">Contents</a>)
<a name="6.10.7" href="#6.10.7"><b> 6.10.7 Null directive</b></a>
- Semantics
+<b> Semantics</b>
1 A preprocessing directive of the form
# new-line
has no effect.
<a name="6.10.8" href="#6.10.8"><b> 6.10.8 Predefined macro names</b></a>
-1 The values of the predefined macros listed in the following subclauses176) (except for
+1 The values of the predefined macros listed in the following subclauses<sup><a href="#note176"><b>176)</b></a></sup> (except for
__FILE__ and __LINE__) remain constant throughout the translation unit.
2 None of these macro names, nor the identifier defined, shall be the subject of a
#define or a #undef preprocessing directive. Any other predefined macro names
first character of dd is a space character if the value is less than 10. If the
date of translation is not available, an implementation-defined valid date
shall be supplied.
- __FILE__ The presumed name of the current source file (a character string literal).177)
+ __FILE__ The presumed name of the current source file (a character string literal).<sup><a href="#note177"><b>177)</b></a></sup>
__LINE__ The presumed line number (within the current source file) of the current
source line (an integer constant).177)
__STDC__ The integer constant 1, intended to indicate a conforming implementation.
-
176) See ''future language directions'' (<a href="#6.11.9">6.11.9</a>).
- 177) The presumed source file name and line number can be changed by the #line directive.
+
<sup><a name="note176" href="#note176"><b>176)</b></a></sup> See ''future language directions'' (<a href="#6.11.9">6.11.9</a>).
+ <sup><a name="note177" href="#note177"><b>177)</b></a></sup> The presumed source file name and line number can be changed by the #line directive.
-[<a name="
#p174" href="p174">page 174</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p174" href="#p174">page 174</a>] (<a href="#Contents">Contents</a>)
- __STDC_VERSION__ The integer constant 201ymmL.178)
+ __STDC_VERSION__ The integer constant 201ymmL.<sup><a href="#note178"><b>178)</b></a></sup>
__TIME__ The time of translation of the preprocessing translation unit: a character
string literal of the form "hh:mm:ss" as in the time generated by the
asctime function. If the time of translation is not available, an
- 178) This macro was not specified in ISO/IEC 9899:1990 and was specified as 199409L in
+ <sup><a name="note178" href="#note178"><b>178)</b></a></sup> This macro was not specified in ISO/IEC 9899:1990 and was specified as 199409L in
ISO/IEC 9899/AMD1:1995 and as 199901L in ISO/IEC 9899:1999. The intention is that this will
remain an integer constant of type long int that is increased with each revision of this International
Standard.
-[<a name="
#p175" href="p175">page 175</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p175" href="#p175">page 175</a>] (<a href="#Contents">Contents</a>)
<a name="6.10.8.3" href="#6.10.8.3"><b> 6.10.8.3 Conditional feature macros</b></a>
1 The following macro names are conditionally defined by the implementation:
adherence to the specifications in <a href="#G">annex G</a> (IEC 60559 compatible complex
arithmetic).
__STDC_LIB_EXT1__ The integer constant 201ymmL, intended to indicate support
- for the extensions defined in <a href="#K">annex K</a> (Bounds-checking interfaces).179)
+ for the extensions defined in <a href="#K">annex K</a> (Bounds-checking interfaces).<sup><a href="#note179"><b>179)</b></a></sup>
__STDC_NO_COMPLEX__ The integer constant 1, intended to indicate that the
implementation does not support complex types or the <a href="#7.3"><complex.h></a>
header.
2 An implementation that defines __STDC_NO_COMPLEX__ shall not define
__STDC_IEC_559_COMPLEX__.
<a name="6.10.9" href="#6.10.9"><b> 6.10.9 Pragma operator</b></a>
- Semantics
+<b> Semantics</b>
1 A unary operator expression of the form:
_Pragma ( string-literal )
is processed as follows: The string literal is destringized by deleting the L prefix, if
preprocessing tokens that are executed as if they were the pp-tokens in a pragma
- 179) The intention is that this will remain an integer constant of type long int that is increased with
+ <sup><a name="note179" href="#note179"><b>179)</b></a></sup> The intention is that this will remain an integer constant of type long int that is increased with
each revision of this International Standard.
-[<a name="
#p176" href="p176">page 176</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p176" href="#p176">page 176</a>] (<a href="#Contents">Contents</a>)
directive. The original four preprocessing tokens in the unary operator expression are
removed.
#define PRAGMA(x) _Pragma(#x)
LISTING ( ..\listing.dir )
-
-
-
-[<a name="#p177" href="p177">page 177</a>] (<a href="#Contents">Contents</a>)
+[<a name="p177" href="#p177">page 177</a>] (<a href="#Contents">Contents</a>)
<a name="6.11" href="#6.11"><b> 6.11 Future language directions</b></a>
<a name="6.11.1" href="#6.11.1"><b> 6.11.1 Floating types</b></a>
<a name="6.11.9" href="#6.11.9"><b> 6.11.9 Predefined macro names</b></a>
1 Macro names beginning with __STDC_ are reserved for future standardization.
-
-
-
-[<a name="#p178" href="p178">page 178</a>] (<a href="#Contents">Contents</a>)
+[<a name="p178" href="#p178">page 178</a>] (<a href="#Contents">Contents</a>)
<a name="7" href="#7"><b> 7. Library</b></a>
the value of a string is the sequence of the values of the contained characters, in order.
2 The decimal-point character is the character used by functions that convert floating-point
numbers to or from character sequences to denote the beginning of the fractional part of
- such character sequences.180) It is represented in the text and examples by a period, but
+ such character sequences.<sup><a href="#note180"><b>180)</b></a></sup> It is represented in the text and examples by a period, but
may be changed by the setlocale function.
3 A null wide character is a wide character with code value zero.
4 A wide string is a contiguous sequence of wide characters terminated by and including
5 A shift sequence is a contiguous sequence of bytes within a multibyte string that
(potentially) causes a change in shift state (see <a href="#5.2.1.2">5.2.1.2</a>). A shift sequence shall not have a
corresponding wide character; it is instead taken to be an adjunct to an adjacent multibyte
- character.181)
+ character.<sup><a href="#note181"><b>181)</b></a></sup>
Forward references: character handling (<a href="#7.4">7.4</a>), the setlocale function (<a href="#7.11.1.1">7.11.1.1</a>).
- 180) The functions that make use of the decimal-point character are the numeric conversion functions
+ <sup><a name="note180" href="#note180"><b>180)</b></a></sup> The functions that make use of the decimal-point character are the numeric conversion functions
(<a href="#7.22.1">7.22.1</a>, <a href="#7.28.4.1">7.28.4.1</a>) and the formatted input/output functions (<a href="#7.21.6">7.21.6</a>, <a href="#7.28.2">7.28.2</a>).
- 181) For state-dependent encodings, the values for MB_CUR_MAX and MB_LEN_MAX shall thus be large
+ <sup><a name="note181" href="#note181"><b>181)</b></a></sup> For state-dependent encodings, the values for MB_CUR_MAX and MB_LEN_MAX shall thus be large
enough to count all the bytes in any complete multibyte character plus at least one adjacent shift
sequence of maximum length. Whether these counts provide for more than one shift sequence is the
implementation's choice.
-[<a name="
#p179" href="p179">page 179</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p179" href="#p179">page 179</a>] (<a href="#Contents">Contents</a>)
<a name="7.1.2" href="#7.1.2"><b> 7.1.2 Standard headers</b></a>
-1 Each library function is declared, with a type that includes a prototype, in a header,182)
+1 Each library function is declared, with a type that includes a prototype, in a header,<sup><a href="#note182"><b>182)</b></a></sup>
whose contents are made available by the #include preprocessing directive. The
header declares a set of related functions, plus any necessary types and additional macros
needed to facilitate their use. Declarations of types described in this clause shall not
include type qualifiers, unless explicitly stated otherwise.
-2 The standard headers are183)
+2 The standard headers are<sup><a href="#note183"><b>183)</b></a></sup>
<a href="#7.2"><assert.h></a> <a href="#7.9"><iso646.h></a> <a href="#7.16"><stdarg.h></a> <a href="#7.23"><string.h></a>
<a href="#7.3"><complex.h></a> <a href="#7.10"><limits.h></a> <a href="#7.17"><stdatomic.h></a> <a href="#7.24"><tgmath.h></a>
<a href="#7.4"><ctype.h></a> <a href="#7.11"><locale.h></a> <a href="#7.18"><stdbool.h></a> <a href="#7.25"><threads.h></a>
- 182) A header is not necessarily a source file, nor are the < and > delimited sequences in header names
+ <sup><a name="note182" href="#note182"><b>182)</b></a></sup> A header is not necessarily a source file, nor are the < and > delimited sequences in header names
necessarily valid source file names.
-
183) The headers <a href="#7.3"><complex.h></a>, <a href="#7.17"><stdatomic.h></a>, and <a href="#7.25"><threads.h></a> are conditional features that
+
<sup><a name="note183" href="#note183"><b>183)</b></a></sup> The headers <a href="#7.3"><complex.h></a>, <a href="#7.17"><stdatomic.h></a>, and <a href="#7.25"><threads.h></a> are conditional features that
implementations need not support; see <a href="#6.10.8.3">6.10.8.3</a>.
-[<a name="
#p180" href="p180">page 180</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p180" href="#p180">page 180</a>] (<a href="#Contents">Contents</a>)
7 A summary of the contents of the standard headers is given in <a href="#B">annex B</a>.
Forward references: diagnostics (<a href="#7.2">7.2</a>).
unless explicitly stated otherwise (see <a href="#7.1.4">7.1.4</a>).
-- All identifiers with external linkage in any of the following subclauses (including the
future library directions) and errno are always reserved for use as identifiers with
- external linkage.184)
+ external linkage.<sup><a href="#note184"><b>184)</b></a></sup>
-- Each identifier with file scope listed in any of the following subclauses (including the
future library directions) is reserved for use as a macro name and as an identifier with
file scope in the same name space if any of its associated headers is included.
- 184) The list of reserved identifiers with external linkage includes math_errhandling, setjmp,
+ <sup><a name="note184" href="#note184"><b>184)</b></a></sup> The list of reserved identifiers with external linkage includes math_errhandling, setjmp,
va_copy, and va_end.
-[<a name="
#p181" href="p181">page 181</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p181" href="#p181">page 181</a>] (<a href="#Contents">Contents</a>)
<a name="7.1.4" href="#7.1.4"><b> 7.1.4 Use of library functions</b></a>
1 Each of the following statements applies unless explicitly stated otherwise in the detailed
the name of the function in parentheses, because the name is then not followed by the left
parenthesis that indicates expansion of a macro function name. For the same syntactic
reason, it is permitted to take the address of a library function even if it is also defined as
- a macro.185) The use of #undef to remove any macro definition will also ensure that an
+ a macro.<sup><a href="#note185"><b>185)</b></a></sup> The use of #undef to remove any macro definition will also ensure that an
actual function is referred to. Any invocation of a library function that is implemented as
a macro shall expand to code that evaluates each of its arguments exactly once, fully
protected by parentheses where necessary, so it is generally safe to use arbitrary
- expressions as arguments.186) Likewise, those function-like macros described in the
+ expressions as arguments.<sup><a href="#note186"><b>186)</b></a></sup> Likewise, those function-like macros described in the
following subclauses may be invoked in an expression anywhere a function with a
- compatible return type could be called.187) All object-like macros listed as expanding to
+ compatible return type could be called.<sup><a href="#note187"><b>187)</b></a></sup> All object-like macros listed as expanding to
- 185) This means that an implementation shall provide an actual function for each library function, even if it
+ <sup><a name="note185" href="#note185"><b>185)</b></a></sup> This means that an implementation shall provide an actual function for each library function, even if it
also provides a macro for that function.
- 186) Such macros might not contain the sequence points that the corresponding function calls do.
- 187) Because external identifiers and some macro names beginning with an underscore are reserved,
+ <sup><a name="note186" href="#note186"><b>186)</b></a></sup> Such macros might not contain the sequence points that the corresponding function calls do.
+ <sup><a name="note187" href="#note187"><b>187)</b></a></sup> Because external identifiers and some macro names beginning with an underscore are reserved,
implementations may provide special semantics for such names. For example, the identifier
_BUILTIN_abs could be used to indicate generation of in-line code for the abs function. Thus, the
appropriate header could specify
implementation. The prototype for the function, which precedes and is hidden by any macro
definition, is thereby revealed also.
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+[<a name="
p182" href="#p182">page 182</a>] (<a href="#Contents">Contents</a>)
integer constant expressions shall additionally be suitable for use in #if preprocessing
directives.
associated header.
3 There is a sequence point immediately before a library function returns.
4 The functions in the standard library are not guaranteed to be reentrant and may modify
- objects with static or thread storage duration.188)
+ objects with static or thread storage duration.<sup><a href="#note188"><b>188)</b></a></sup>
5 Unless explicitly stated otherwise in the detailed descriptions that follow, library
functions shall prevent data races as follows: A library function shall not directly or
indirectly access objects accessible by threads other than the current thread unless the
objects are accessed directly or indirectly via the function's arguments. A library
function shall not directly or indirectly modify objects accessible by threads other than
the current thread unless the objects are accessed directly or indirectly via the function's
- non-const arguments.189) Implementations may share their own internal objects between
+ non-const arguments.<sup><a href="#note189"><b>189)</b></a></sup> Implementations may share their own internal objects between
threads if the objects are not visible to users and are protected against data races.
6 Unless otherwise specified, library functions shall perform all operations solely within the
- current thread if those operations have effects that are visible to users.190)
+ current thread if those operations have effects that are visible to users.<sup><a href="#note190"><b>190)</b></a></sup>
7 EXAMPLE The function atoi may be used in any of several ways:
-- by use of its associated header (possibly generating a macro expansion)
#include <a href="#7.22"><stdlib.h></a>
- 188) Thus, a signal handler cannot, in general, call standard library functions.
- 189) This means, for example, that an implementation is not permitted to use a static object for internal
+ <sup><a name="note188" href="#note188"><b>188)</b></a></sup> Thus, a signal handler cannot, in general, call standard library functions.
+ <sup><a name="note189" href="#note189"><b>189)</b></a></sup> This means, for example, that an implementation is not permitted to use a static object for internal
purposes without synchronization because it could cause a data race even in programs that do not
explicitly share objects between threads.
- 190) This allows implementations to parallelize operations if there are no visible side effects.
+ <sup><a name="note190" href="#note190"><b>190)</b></a></sup> This allows implementations to parallelize operations if there are no visible side effects.
-[<a name="
#p183" href="p183">page 183</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p183" href="#p183">page 183</a>] (<a href="#Contents">Contents</a>)
#include <a href="#7.22"><stdlib.h></a>
#undef atoi
/* ... */
i = atoi(str);
-
-
-
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+[<a name="p184" href="#p184">page 184</a>] (<a href="#Contents">Contents</a>)
<a name="7.2" href="#7.2"><b> 7.2 Diagnostics <assert.h></b></a>
1 The header <a href="#7.2"><assert.h></a> defines the assert and static_assert macros and
expands to _Static_assert.
<a name="7.2.1" href="#7.2.1"><b> 7.2.1 Program diagnostics</b></a>
<a name="7.2.1.1" href="#7.2.1.1"><b> 7.2.1.1 The assert macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.2"><assert.h></a>
void assert(scalar expression);
- Description
+<b> Description</b>
2 The assert macro puts diagnostic tests into programs; it expands to a void expression.
When it is executed, if expression (which shall have a scalar type) is false (that is,
compares equal to 0), the assert macro writes information about the particular call that
failed (including the text of the argument, the name of the source file, the source line
number, and the name of the enclosing function -- the latter are respectively the values of
the preprocessing macros __FILE__ and __LINE__ and of the identifier
- __func__) on the standard error stream in an implementation-defined format.191) It
+ __func__) on the standard error stream in an implementation-defined format.<sup><a href="#note191"><b>191)</b></a></sup> It
then calls the abort function.
- 191) The message written might be of the form:
+ <sup><a name="note191" href="#note191"><b>191)</b></a></sup> The message written might be of the form:
Assertion failed: expression, function abc, file xyz, line nnn.
+[<a name="p185" href="#p185">page 185</a>] (<a href="#Contents">Contents</a>)
-[<a name="#p185" href="p185">page 185</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The assert macro returns no value.
Forward references: the abort function (<a href="#7.22.4.1">7.22.4.1</a>).
-
-
-
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+[<a name="p186" href="#p186">page 186</a>] (<a href="#Contents">Contents</a>)
<a name="7.3" href="#7.3"><b> 7.3 Complex arithmetic <complex.h></b></a>
<a name="7.3.1" href="#7.3.1"><b> 7.3.1 Introduction</b></a>
1 The header <a href="#7.3"><complex.h></a> defines macros and declares functions that support complex
- arithmetic.192)
+ arithmetic.<sup><a href="#note192"><b>192)</b></a></sup>
2 Implementations that define the macro __STDC_NO_COMPLEX__ need not provide
this header nor support any of its facilities.
3 Each synopsis specifies a family of functions consisting of a principal function with one
expands to _Complex; the macro
_Complex_I
expands to a constant expression of type const float _Complex, with the value of
- the imaginary unit.193)
+ the imaginary unit.<sup><a href="#note193"><b>193)</b></a></sup>
5 The macros
imaginary
and
_Imaginary_I
- are defined if and only if the implementation supports imaginary types;194) if defined,
+ are defined if and only if the implementation supports imaginary types;<sup><a href="#note194"><b>194)</b></a></sup> if defined,
they expand to _Imaginary and a constant expression of type const float
_Imaginary with the value of the imaginary unit.
6 The macro
7 Notwithstanding the provisions of <a href="#7.1.3">7.1.3</a>, a program may undefine and perhaps then
redefine the macros complex, imaginary, and I.
-
192) See ''future library directions'' (<a href="#7.30.1">7.30.1</a>).
- 193) The imaginary unit is a number i such that i 2 = -1.
-
194) A specification for imaginary types is in informative <a href="#G">annex G</a>.
+
<sup><a name="note192" href="#note192"><b>192)</b></a></sup> See ''future library directions'' (<a href="#7.30.1">7.30.1</a>).
+ <sup><a name="note193" href="#note193"><b>193)</b></a></sup> The imaginary unit is a number i such that i 2 = -1.
+
<sup><a name="note194" href="#note194"><b>194)</b></a></sup> A specification for imaginary types is in informative <a href="#G">annex G</a>.
-[<a name="
#p187" href="p187">page 187</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p187" href="#p187">page 187</a>] (<a href="#Contents">Contents</a>)
Forward references: IEC 60559-compatible complex arithmetic (<a href="#G">annex G</a>).
<a name="7.3.2" href="#7.3.2"><b> 7.3.2 Conventions</b></a>
the finite endpoint of the cut along the negative real axis approaches the cut from above,
so the cut maps to the positive imaginary axis.
<a name="7.3.4" href="#7.3.4"><b> 7.3.4 The CX_LIMITED_RANGE pragma</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
#pragma STDC CX_LIMITED_RANGE on-off-switch
- Description
+<b> Description</b>
2 The usual mathematical formulas for complex multiply, divide, and absolute value are
problematic because of their treatment of infinities and because of undue overflow and
underflow. The CX_LIMITED_RANGE pragma can be used to inform the
implementation that (where the state is ''on'') the usual mathematical formulas are
- acceptable.195) The pragma can occur either outside external declarations or preceding all
+ acceptable.<sup><a href="#note195"><b>195)</b></a></sup> The pragma can occur either outside external declarations or preceding all
explicit declarations and statements inside a compound statement. When outside external
declarations, the pragma takes effect from its occurrence until another
CX_LIMITED_RANGE pragma is encountered, or until the end of the translation unit.
compound statement), or until the end of the compound statement; at the end of a
compound statement the state for the pragma is restored to its condition just before the
-[<a name="
#p188" href="p188">page 188</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p188" href="#p188">page 188</a>] (<a href="#Contents">Contents</a>)
compound statement. If this pragma is used in any other context, the behavior is
undefined. The default state for the pragma is ''off''.
<a name="7.3.5" href="#7.3.5"><b> 7.3.5 Trigonometric functions</b></a>
<a name="7.3.5.1" href="#7.3.5.1"><b> 7.3.5.1 The cacos functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex cacos(double complex z);
float complex cacosf(float complex z);
long double complex cacosl(long double complex z);
- Description
+<b> Description</b>
2 The cacos functions compute the complex arc cosine of z, with branch cuts outside the
interval [-1, +1] along the real axis.
- Returns
+<b> Returns</b>
3 The cacos functions return the complex arc cosine value, in the range of a strip
mathematically unbounded along the imaginary axis and in the interval [0, pi ] along the
real axis.
<a name="7.3.5.2" href="#7.3.5.2"><b> 7.3.5.2 The casin functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex casin(double complex z);
float complex casinf(float complex z);
long double complex casinl(long double complex z);
- Description
+<b> Description</b>
2 The casin functions compute the complex arc sine of z, with branch cuts outside the
interval [-1, +1] along the real axis.
- Returns
+<b> Returns</b>
3 The casin functions return the complex arc sine value, in the range of a strip
mathematically unbounded along the imaginary axis and in the interval [-pi /2, +pi /2]
- 195) The purpose of the pragma is to allow the implementation to use the formulas:
+ <sup><a name="note195" href="#note195"><b>195)</b></a></sup> The purpose of the pragma is to allow the implementation to use the formulas:
(x + iy) x (u + iv) = (xu - yv) + i(yu + xv)
(x + iy) / (u + iv) = [(xu + yv) + i(yu - xv)]/(u2 + v 2 )
- | x + iy | = sqrt: x 2 + y 2
+ | x + iy | = (sqrt) x 2 + y 2
-----
where the programmer can determine they are safe.
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#p189" href="p189">page 189</a>] (<a href="#Contents">Contents</a>)
+[<a name="
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along the real axis.
<a name="7.3.5.3" href="#7.3.5.3"><b> 7.3.5.3 The catan functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex catan(double complex z);
float complex catanf(float complex z);
long double complex catanl(long double complex z);
- Description
+<b> Description</b>
2 The catan functions compute the complex arc tangent of z, with branch cuts outside the
interval [-i, +i] along the imaginary axis.
- Returns
+<b> Returns</b>
3 The catan functions return the complex arc tangent value, in the range of a strip
mathematically unbounded along the imaginary axis and in the interval [-pi /2, +pi /2]
along the real axis.
<a name="7.3.5.4" href="#7.3.5.4"><b> 7.3.5.4 The ccos functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex ccos(double complex z);
float complex ccosf(float complex z);
long double complex ccosl(long double complex z);
- Description
+<b> Description</b>
2 The ccos functions compute the complex cosine of z.
- Returns
+<b> Returns</b>
3 The ccos functions return the complex cosine value.
<a name="7.3.5.5" href="#7.3.5.5"><b> 7.3.5.5 The csin functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex csin(double complex z);
float complex csinf(float complex z);
long double complex csinl(long double complex z);
- Description
+<b> Description</b>
2 The csin functions compute the complex sine of z.
+[<a name="p190" href="#p190">page 190</a>] (<a href="#Contents">Contents</a>)
-
-[<a name="#p190" href="p190">page 190</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The csin functions return the complex sine value.
<a name="7.3.5.6" href="#7.3.5.6"><b> 7.3.5.6 The ctan functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex ctan(double complex z);
float complex ctanf(float complex z);
long double complex ctanl(long double complex z);
- Description
+<b> Description</b>
2 The ctan functions compute the complex tangent of z.
- Returns
+<b> Returns</b>
3 The ctan functions return the complex tangent value.
<a name="7.3.6" href="#7.3.6"><b> 7.3.6 Hyperbolic functions</b></a>
<a name="7.3.6.1" href="#7.3.6.1"><b> 7.3.6.1 The cacosh functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex cacosh(double complex z);
float complex cacoshf(float complex z);
long double complex cacoshl(long double complex z);
- Description
+<b> Description</b>
2 The cacosh functions compute the complex arc hyperbolic cosine of z, with a branch
cut at values less than 1 along the real axis.
- Returns
+<b> Returns</b>
3 The cacosh functions return the complex arc hyperbolic cosine value, in the range of a
half-strip of nonnegative values along the real axis and in the interval [-ipi , +ipi ] along the
imaginary axis.
<a name="7.3.6.2" href="#7.3.6.2"><b> 7.3.6.2 The casinh functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex casinh(double complex z);
float complex casinhf(float complex z);
long double complex casinhl(long double complex z);
+[<a name="p191" href="#p191">page 191</a>] (<a href="#Contents">Contents</a>)
-
-[<a name="#p191" href="p191">page 191</a>] (<a href="#Contents">Contents</a>)
-
- Description
+<b> Description</b>
2 The casinh functions compute the complex arc hyperbolic sine of z, with branch cuts
outside the interval [-i, +i] along the imaginary axis.
- Returns
+<b> Returns</b>
3 The casinh functions return the complex arc hyperbolic sine value, in the range of a
strip mathematically unbounded along the real axis and in the interval [-ipi /2, +ipi /2]
along the imaginary axis.
<a name="7.3.6.3" href="#7.3.6.3"><b> 7.3.6.3 The catanh functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex catanh(double complex z);
float complex catanhf(float complex z);
long double complex catanhl(long double complex z);
- Description
+<b> Description</b>
2 The catanh functions compute the complex arc hyperbolic tangent of z, with branch
cuts outside the interval [-1, +1] along the real axis.
- Returns
+<b> Returns</b>
3 The catanh functions return the complex arc hyperbolic tangent value, in the range of a
strip mathematically unbounded along the real axis and in the interval [-ipi /2, +ipi /2]
along the imaginary axis.
<a name="7.3.6.4" href="#7.3.6.4"><b> 7.3.6.4 The ccosh functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex ccosh(double complex z);
float complex ccoshf(float complex z);
long double complex ccoshl(long double complex z);
- Description
+<b> Description</b>
2 The ccosh functions compute the complex hyperbolic cosine of z.
- Returns
+<b> Returns</b>
3 The ccosh functions return the complex hyperbolic cosine value.
-
-
-
-[<a name="#p192" href="p192">page 192</a>] (<a href="#Contents">Contents</a>)
+[<a name="p192" href="#p192">page 192</a>] (<a href="#Contents">Contents</a>)
<a name="7.3.6.5" href="#7.3.6.5"><b> 7.3.6.5 The csinh functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex csinh(double complex z);
float complex csinhf(float complex z);
long double complex csinhl(long double complex z);
- Description
+<b> Description</b>
2 The csinh functions compute the complex hyperbolic sine of z.
- Returns
+<b> Returns</b>
3 The csinh functions return the complex hyperbolic sine value.
<a name="7.3.6.6" href="#7.3.6.6"><b> 7.3.6.6 The ctanh functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex ctanh(double complex z);
float complex ctanhf(float complex z);
long double complex ctanhl(long double complex z);
- Description
+<b> Description</b>
2 The ctanh functions compute the complex hyperbolic tangent of z.
- Returns
+<b> Returns</b>
3 The ctanh functions return the complex hyperbolic tangent value.
<a name="7.3.7" href="#7.3.7"><b> 7.3.7 Exponential and logarithmic functions</b></a>
<a name="7.3.7.1" href="#7.3.7.1"><b> 7.3.7.1 The cexp functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex cexp(double complex z);
float complex cexpf(float complex z);
long double complex cexpl(long double complex z);
- Description
+<b> Description</b>
2 The cexp functions compute the complex base-e exponential of z.
- Returns
+<b> Returns</b>
3 The cexp functions return the complex base-e exponential value.
-
-
-[<a name="#p193" href="p193">page 193</a>] (<a href="#Contents">Contents</a>)
+[<a name="p193" href="#p193">page 193</a>] (<a href="#Contents">Contents</a>)
<a name="7.3.7.2" href="#7.3.7.2"><b> 7.3.7.2 The clog functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex clog(double complex z);
float complex clogf(float complex z);
long double complex clogl(long double complex z);
- Description
+<b> Description</b>
2 The clog functions compute the complex natural (base-e) logarithm of z, with a branch
cut along the negative real axis.
- Returns
+<b> Returns</b>
3 The clog functions return the complex natural logarithm value, in the range of a strip
mathematically unbounded along the real axis and in the interval [-ipi , +ipi ] along the
imaginary axis.
<a name="7.3.8" href="#7.3.8"><b> 7.3.8 Power and absolute-value functions</b></a>
<a name="7.3.8.1" href="#7.3.8.1"><b> 7.3.8.1 The cabs functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double cabs(double complex z);
float cabsf(float complex z);
long double cabsl(long double complex z);
- Description
+<b> Description</b>
2 The cabs functions compute the complex absolute value (also called norm, modulus, or
magnitude) of z.
- Returns
+<b> Returns</b>
3 The cabs functions return the complex absolute value.
<a name="7.3.8.2" href="#7.3.8.2"><b> 7.3.8.2 The cpow functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex cpow(double complex x, double complex y);
float complex cpowf(float complex x, float complex y);
long double complex cpowl(long double complex x,
long double complex y);
+[<a name="p194" href="#p194">page 194</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p194" href="p194">page 194</a>] (<a href="#Contents">Contents</a>)
-
- Description
+<b> Description</b>
2 The cpow functions compute the complex power function xy , with a branch cut for the
first parameter along the negative real axis.
- Returns
+<b> Returns</b>
3 The cpow functions return the complex power function value.
<a name="7.3.8.3" href="#7.3.8.3"><b> 7.3.8.3 The csqrt functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex csqrt(double complex z);
float complex csqrtf(float complex z);
long double complex csqrtl(long double complex z);
- Description
+<b> Description</b>
2 The csqrt functions compute the complex square root of z, with a branch cut along the
negative real axis.
- Returns
+<b> Returns</b>
3 The csqrt functions return the complex square root value, in the range of the right half-
plane (including the imaginary axis).
<a name="7.3.9" href="#7.3.9"><b> 7.3.9 Manipulation functions</b></a>
<a name="7.3.9.1" href="#7.3.9.1"><b> 7.3.9.1 The carg functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double carg(double complex z);
float cargf(float complex z);
long double cargl(long double complex z);
- Description
+<b> Description</b>
2 The carg functions compute the argument (also called phase angle) of z, with a branch
cut along the negative real axis.
- Returns
+<b> Returns</b>
3 The carg functions return the value of the argument in the interval [-pi , +pi ].
-
-
-
-[<a name="#p195" href="p195">page 195</a>] (<a href="#Contents">Contents</a>)
+[<a name="p195" href="#p195">page 195</a>] (<a href="#Contents">Contents</a>)
<a name="7.3.9.2" href="#7.3.9.2"><b> 7.3.9.2 The cimag functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double cimag(double complex z);
float cimagf(float complex z);
long double cimagl(long double complex z);
- Description
-2 The cimag functions compute the imaginary part of z.196)
- Returns
+<b> Description</b>
+2 The cimag functions compute the imaginary part of z.<sup><a href="#note196"><b>196)</b></a></sup>
+<b> Returns</b>
3 The cimag functions return the imaginary part value (as a real).
<a name="7.3.9.3" href="#7.3.9.3"><b> 7.3.9.3 The CMPLX macros</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex CMPLX(double x, double y);
float complex CMPLXF(float x, float y);
long double complex CMPLXL(long double x, long double y);
- Description
+<b> Description</b>
2 The CMPLX macros expand to an expression of the specified complex type, with the real
part having the (converted) value of x and the imaginary part having the (converted)
value of y.
Recommended practice
3 The resulting expression should be suitable for use as an initializer for an object with
static or thread storage duration, provided both arguments are likewise suitable.
- Returns
+<b> Returns</b>
4 The CMPLX macros return the complex value x + i y.
5 NOTE These macros act as if the implementation supported imaginary types and the definitions were:
#define CMPLX(x, y) ((double complex)((double)(x) + \
- 196) For a variable z of complex type, z == creal(z) + cimag(z)*I.
+ <sup><a name="note196" href="#note196"><b>196)</b></a></sup> For a variable z of complex type, z == creal(z) + cimag(z)*I.
-[<a name="
#p196" href="p196">page 196</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p196" href="#p196">page 196</a>] (<a href="#Contents">Contents</a>)
<a name="7.3.9.4" href="#7.3.9.4"><b> 7.3.9.4 The conj functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex conj(double complex z);
float complex conjf(float complex z);
long double complex conjl(long double complex z);
- Description
+<b> Description</b>
2 The conj functions compute the complex conjugate of z, by reversing the sign of its
imaginary part.
- Returns
+<b> Returns</b>
3 The conj functions return the complex conjugate value.
<a name="7.3.9.5" href="#7.3.9.5"><b> 7.3.9.5 The cproj functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double complex cproj(double complex z);
float complex cprojf(float complex z);
long double complex cprojl(long double complex z);
- Description
+<b> Description</b>
2 The cproj functions compute a projection of z onto the Riemann sphere: z projects to
z except that all complex infinities (even those with one infinite part and one NaN part)
project to positive infinity on the real axis. If z has an infinite part, then cproj(z) is
equivalent to
INFINITY + I * copysign(0.0, cimag(z))
- Returns
+<b> Returns</b>
3 The cproj functions return the value of the projection onto the Riemann sphere.
<a name="7.3.9.6" href="#7.3.9.6"><b> 7.3.9.6 The creal functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.3"><complex.h></a>
double creal(double complex z);
float crealf(float complex z);
long double creall(long double complex z);
- Description
-2 The creal functions compute the real part of z.197)
+<b> Description</b>
+2 The creal functions compute the real part of z.<sup><a href="#note197"><b>197)</b></a></sup>
+[<a name="p197" href="#p197">page 197</a>] (<a href="#Contents">Contents</a>)
-[<a name="#p197" href="p197">page 197</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The creal functions return the real part value.
- 197) For a variable z of complex type, z == creal(z) + cimag(z)*I.
+ <sup><a name="note197" href="#note197"><b>197)</b></a></sup> For a variable z of complex type, z == creal(z) + cimag(z)*I.
-[<a name="
#p198" href="p198">page 198</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p198" href="#p198">page 198</a>] (<a href="#Contents">Contents</a>)
<a name="7.4" href="#7.4"><b> 7.4 Character handling <ctype.h></b></a>
1 The header <a href="#7.4"><ctype.h></a> declares several functions useful for classifying and mapping
- characters.198) In all cases the argument is an int, the value of which shall be
+ characters.<sup><a href="#note198"><b>198)</b></a></sup> In all cases the argument is an int, the value of which shall be
representable as an unsigned char or shall equal the value of the macro EOF. If the
argument has any other value, the behavior is undefined.
2 The behavior of these functions is affected by the current locale. Those functions that
3 The term printing character refers to a member of a locale-specific set of characters, each
of which occupies one printing position on a display device; the term control character
refers to a member of a locale-specific set of characters that are not printing
- characters.199) All letters and digits are printing characters.
+ characters.<sup><a href="#note199"><b>199)</b></a></sup> All letters and digits are printing characters.
Forward references: EOF (<a href="#7.21.1">7.21.1</a>), localization (<a href="#7.11">7.11</a>).
<a name="7.4.1" href="#7.4.1"><b> 7.4.1 Character classification functions</b></a>
1 The functions in this subclause return nonzero (true) if and only if the value of the
argument c conforms to that in the description of the function.
<a name="7.4.1.1" href="#7.4.1.1"><b> 7.4.1.1 The isalnum function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int isalnum(int c);
- Description
+<b> Description</b>
2 The isalnum function tests for any character for which isalpha or isdigit is true.
<a name="7.4.1.2" href="#7.4.1.2"><b> 7.4.1.2 The isalpha function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int isalpha(int c);
- Description
+<b> Description</b>
2 The isalpha function tests for any character for which isupper or islower is true,
or any character that is one of a locale-specific set of alphabetic characters for which
-
198) See ''future library directions'' (<a href="#7.30.2">7.30.2</a>).
- 199) In an implementation that uses the seven-bit US ASCII character set, the printing characters are those
+
<sup><a name="note198" href="#note198"><b>198)</b></a></sup> See ''future library directions'' (<a href="#7.30.2">7.30.2</a>).
+ <sup><a name="note199" href="#note199"><b>199)</b></a></sup> In an implementation that uses the seven-bit US ASCII character set, the printing characters are those
whose values lie from 0x20 (space) through 0x7E (tilde); the control characters are those whose
values lie from 0 (NUL) through 0x1F (US), and the character 0x7F (DEL).
-[<a name="
#p199" href="p199">page 199</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p199" href="#p199">page 199</a>] (<a href="#Contents">Contents</a>)
- none of iscntrl, isdigit, ispunct, or isspace is true.200) In the "C" locale,
+ none of iscntrl, isdigit, ispunct, or isspace is true.<sup><a href="#note200"><b>200)</b></a></sup> In the "C" locale,
isalpha returns true only for the characters for which isupper or islower is true.
<a name="7.4.1.3" href="#7.4.1.3"><b> 7.4.1.3 The isblank function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int isblank(int c);
- Description
+<b> Description</b>
2 The isblank function tests for any character that is a standard blank character or is one
of a locale-specific set of characters for which isspace is true and that is used to
separate words within a line of text. The standard blank characters are the following:
space (' '), and horizontal tab ('\t'). In the "C" locale, isblank returns true only
for the standard blank characters.
<a name="7.4.1.4" href="#7.4.1.4"><b> 7.4.1.4 The iscntrl function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int iscntrl(int c);
- Description
+<b> Description</b>
2 The iscntrl function tests for any control character.
<a name="7.4.1.5" href="#7.4.1.5"><b> 7.4.1.5 The isdigit function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int isdigit(int c);
- Description
+<b> Description</b>
2 The isdigit function tests for any decimal-digit character (as defined in <a href="#5.2.1">5.2.1</a>).
<a name="7.4.1.6" href="#7.4.1.6"><b> 7.4.1.6 The isgraph function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int isgraph(int c);
- 200) The functions islower and isupper test true or false separately for each of these additional
+ <sup><a name="note200" href="#note200"><b>200)</b></a></sup> The functions islower and isupper test true or false separately for each of these additional
characters; all four combinations are possible.
-[<a name="
#p200" href="p200">page 200</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p200" href="#p200">page 200</a>] (<a href="#Contents">Contents</a>)
- Description
+<b> Description</b>
2 The isgraph function tests for any printing character except space (' ').
<a name="7.4.1.7" href="#7.4.1.7"><b> 7.4.1.7 The islower function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int islower(int c);
- Description
+<b> Description</b>
2 The islower function tests for any character that is a lowercase letter or is one of a
locale-specific set of characters for which none of iscntrl, isdigit, ispunct, or
isspace is true. In the "C" locale, islower returns true only for the lowercase
letters (as defined in <a href="#5.2.1">5.2.1</a>).
<a name="7.4.1.8" href="#7.4.1.8"><b> 7.4.1.8 The isprint function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int isprint(int c);
- Description
+<b> Description</b>
2 The isprint function tests for any printing character including space (' ').
<a name="7.4.1.9" href="#7.4.1.9"><b> 7.4.1.9 The ispunct function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int ispunct(int c);
- Description
+<b> Description</b>
2 The ispunct function tests for any printing character that is one of a locale-specific set
of punctuation characters for which neither isspace nor isalnum is true. In the "C"
locale, ispunct returns true for every printing character for which neither isspace
nor isalnum is true.
<a name="7.4.1.10" href="#7.4.1.10"><b> 7.4.1.10 The isspace function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int isspace(int c);
- Description
+<b> Description</b>
2 The isspace function tests for any character that is a standard white-space character or
is one of a locale-specific set of characters for which isalnum is false. The standard
-[<a name="
#p201" href="p201">page 201</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p201" href="#p201">page 201</a>] (<a href="#Contents">Contents</a>)
white-space characters are the following: space (' '), form feed ('\f'), new-line
('\n'), carriage return ('\r'), horizontal tab ('\t'), and vertical tab ('\v'). In the
"C" locale, isspace returns true only for the standard white-space characters.
<a name="7.4.1.11" href="#7.4.1.11"><b> 7.4.1.11 The isupper function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int isupper(int c);
- Description
+<b> Description</b>
2 The isupper function tests for any character that is an uppercase letter or is one of a
locale-specific set of characters for which none of iscntrl, isdigit, ispunct, or
isspace is true. In the "C" locale, isupper returns true only for the uppercase
letters (as defined in <a href="#5.2.1">5.2.1</a>).
<a name="7.4.1.12" href="#7.4.1.12"><b> 7.4.1.12 The isxdigit function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int isxdigit(int c);
- Description
+<b> Description</b>
2 The isxdigit function tests for any hexadecimal-digit character (as defined in <a href="#6.4.4.1">6.4.4.1</a>).
<a name="7.4.2" href="#7.4.2"><b> 7.4.2 Character case mapping functions</b></a>
<a name="7.4.2.1" href="#7.4.2.1"><b> 7.4.2.1 The tolower function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int tolower(int c);
- Description
+<b> Description</b>
2 The tolower function converts an uppercase letter to a corresponding lowercase letter.
- Returns
+<b> Returns</b>
3 If the argument is a character for which isupper is true and there are one or more
corresponding characters, as specified by the current locale, for which islower is true,
the tolower function returns one of the corresponding characters (always the same one
for any given locale); otherwise, the argument is returned unchanged.
-
-
-
-[<a name="#p202" href="p202">page 202</a>] (<a href="#Contents">Contents</a>)
+[<a name="p202" href="#p202">page 202</a>] (<a href="#Contents">Contents</a>)
<a name="7.4.2.2" href="#7.4.2.2"><b> 7.4.2.2 The toupper function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.4"><ctype.h></a>
int toupper(int c);
- Description
+<b> Description</b>
2 The toupper function converts a lowercase letter to a corresponding uppercase letter.
- Returns
+<b> Returns</b>
3 If the argument is a character for which islower is true and there are one or more
corresponding characters, as specified by the current locale, for which isupper is true,
the toupper function returns one of the corresponding characters (always the same one
for any given locale); otherwise, the argument is returned unchanged.
-
-
-
-[<a name="#p203" href="p203">page 203</a>] (<a href="#Contents">Contents</a>)
+[<a name="p203" href="#p203">page 203</a>] (<a href="#Contents">Contents</a>)
<a name="7.5" href="#7.5"><b> 7.5 Errors <errno.h></b></a>
1 The header <a href="#7.5"><errno.h></a> defines several macros, all relating to the reporting of error
which expand to integer constant expressions with type int, distinct positive values, and
which are suitable for use in #if preprocessing directives; and
errno
- which expands to a modifiable lvalue201) that has type int and thread local storage
+ which expands to a modifiable lvalue<sup><a href="#note201"><b>201)</b></a></sup> that has type int and thread local storage
duration, the value of which is set to a positive error number by several library functions.
If a macro definition is suppressed in order to access an actual object, or a program
defines an identifier with the name errno, the behavior is undefined.
3 The value of errno in the initial thread is zero at program startup (the initial value of
errno in other threads is an indeterminate value), but is never set to zero by any library
- function.202) The value of errno may be set to nonzero by a library function call
+ function.<sup><a href="#note202"><b>202)</b></a></sup> The value of errno may be set to nonzero by a library function call
whether or not there is an error, provided the use of errno is not documented in the
description of the function in this International Standard.
4 Additional macro definitions, beginning with E and a digit or E and an uppercase
- letter,203) may also be specified by the implementation.
+ letter,<sup><a href="#note203"><b>203)</b></a></sup> may also be specified by the implementation.
- 201) The macro errno need not be the identifier of an object. It might expand to a modifiable lvalue
+ <sup><a name="note201" href="#note201"><b>201)</b></a></sup> The macro errno need not be the identifier of an object. It might expand to a modifiable lvalue
resulting from a function call (for example, *errno()).
- 202) Thus, a program that uses errno for error checking should set it to zero before a library function call,
+ <sup><a name="note202" href="#note202"><b>202)</b></a></sup> Thus, a program that uses errno for error checking should set it to zero before a library function call,
then inspect it before a subsequent library function call. Of course, a library function can save the
value of errno on entry and then set it to zero, as long as the original value is restored if errno's
value is still zero just before the return.
-
203) See ''future library directions'' (<a href="#7.30.3">7.30.3</a>).
+
<sup><a name="note203" href="#note203"><b>203)</b></a></sup> See ''future library directions'' (<a href="#7.30.3">7.30.3</a>).
-[<a name="
#p204" href="p204">page 204</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p204" href="#p204">page 204</a>] (<a href="#Contents">Contents</a>)
<a name="7.6" href="#7.6"><b> 7.6 Floating-point environment <fenv.h></b></a>
1 The header <a href="#7.6"><fenv.h></a> defines several macros, and declares types and functions that
provide access to the floating-point environment. The floating-point environment refers
collectively to any floating-point status flags and control modes supported by the
- implementation.204) A floating-point status flag is a system variable whose value is set
+ implementation.<sup><a href="#note204"><b>204)</b></a></sup> A floating-point status flag is a system variable whose value is set
(but never cleared) when a floating-point exception is raised, which occurs as a side effect
- of exceptional floating-point arithmetic to provide auxiliary information.205) A floating-
+ of exceptional floating-point arithmetic to provide auxiliary information.<sup><a href="#note205"><b>205)</b></a></sup> A floating-
point control mode is a system variable whose value may be set by the user to affect the
subsequent behavior of floating-point arithmetic.
2 The floating-point environment has thread storage duration. The initial state for a
thread's floating-point environment is the current state of the floating-point environment
of the thread that creates it at the time of creation.
3 Certain programming conventions support the intended model of use for the floating-
- point environment:206)
+ point environment:<sup><a href="#note206"><b>206)</b></a></sup>
-- a function call does not alter its caller's floating-point control modes, clear its caller's
floating-point status flags, nor depend on the state of its caller's floating-point status
flags unless the function is so documented;
implementation associates with the flags.
- 204) This header is designed to support the floating-point exception status flags and directed-rounding
+ <sup><a name="note204" href="#note204"><b>204)</b></a></sup> This header is designed to support the floating-point exception status flags and directed-rounding
control modes required by IEC 60559, and other similar floating-point state information. It is also
designed to facilitate code portability among all systems.
- 205) A floating-point status flag is not an object and can be set more than once within an expression.
- 206) With these conventions, a programmer can safely assume default floating-point control modes (or be
+ <sup><a name="note205" href="#note205"><b>205)</b></a></sup> A floating-point status flag is not an object and can be set more than once within an expression.
+ <sup><a name="note206" href="#note206"><b>206)</b></a></sup> With these conventions, a programmer can safely assume default floating-point control modes (or be
unaware of them). The responsibilities associated with accessing the floating-point environment fall
on the programmer or program that does so explicitly.
-[<a name="
#p205" href="p205">page 205</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p205" href="#p205">page 205</a>] (<a href="#Contents">Contents</a>)
6 Each of the macros
FE_DIVBYZERO
FE_OVERFLOW
FE_UNDERFLOW
is defined if and only if the implementation supports the floating-point exception by
- means of the functions in 7.6.2.207) Additional implementation-defined floating-point
+ means of the functions in 7.6.2.<sup><a href="#note207"><b>207)</b></a></sup> Additional implementation-defined floating-point
exceptions, with macro definitions beginning with FE_ and an uppercase letter, may also
be specified by the implementation. The defined macros expand to integer constant
expressions with values such that bitwise ORs of all combinations of the macros result in
distinct values, and furthermore, bitwise ANDs of all combinations of the macros result in
- zero.208)
+ zero.<sup><a href="#note208"><b>208)</b></a></sup>
7 The macro
FE_ALL_EXCEPT
is simply the bitwise OR of all floating-point exception macros defined by the
Additional implementation-defined rounding directions, with macro definitions beginning
with FE_ and an uppercase letter, may also be specified by the implementation. The
defined macros expand to integer constant expressions whose values are distinct
- nonnegative values.209)
+ nonnegative values.<sup><a href="#note209"><b>209)</b></a></sup>
9 The macro
- 207) The implementation supports a floating-point exception if there are circumstances where a call to at
+ <sup><a name="note207" href="#note207"><b>207)</b></a></sup> The implementation supports a floating-point exception if there are circumstances where a call to at
least one of the functions in <a href="#7.6.2">7.6.2</a>, using the macro as the appropriate argument, will succeed. It is not
necessary for all the functions to succeed all the time.
- 208) The macros should be distinct powers of two.
- 209) Even though the rounding direction macros may expand to constants corresponding to the values of
+ <sup><a name="note208" href="#note208"><b>208)</b></a></sup> The macros should be distinct powers of two.
+ <sup><a name="note209" href="#note209"><b>209)</b></a></sup> Even though the rounding direction macros may expand to constants corresponding to the values of
FLT_ROUNDS, they are not required to do so.
-[<a name="
#p206" href="p206">page 206</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p206" href="#p206">page 206</a>] (<a href="#Contents">Contents</a>)
FE_DFL_ENV
represents the default floating-point environment -- the one installed at program startup
FE_ and an uppercase letter, and having type ''pointer to const-qualified fenv_t'', may
also be specified by the implementation.
<a name="7.6.1" href="#7.6.1"><b> 7.6.1 The FENV_ACCESS pragma</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.6"><fenv.h></a>
#pragma STDC FENV_ACCESS on-off-switch
- Description
+<b> Description</b>
2 The FENV_ACCESS pragma provides a means to inform the implementation when a
program might access the floating-point environment to test floating-point status flags or
- run under non-default floating-point control modes.210) The pragma shall occur either
+ run under non-default floating-point control modes.<sup><a href="#note210"><b>210)</b></a></sup> The pragma shall occur either
outside external declarations or preceding all explicit declarations and statements inside a
compound statement. When outside external declarations, the pragma takes effect from
its occurrence until another FENV_ACCESS pragma is encountered, or until the end of
- 210) The purpose of the FENV_ACCESS pragma is to allow certain optimizations that could subvert flag
+ <sup><a name="note210" href="#note210"><b>210)</b></a></sup> The purpose of the FENV_ACCESS pragma is to allow certain optimizations that could subvert flag
tests and mode changes (e.g., global common subexpression elimination, code motion, and constant
folding). In general, if the state of FENV_ACCESS is ''off'', the translator can assume that default
modes are in effect and the flags are not tested.
-[<a name="
#p207" href="p207">page 207</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p207" href="#p207">page 207</a>] (<a href="#Contents">Contents</a>)
3 EXAMPLE
#include <a href="#7.6"><fenv.h></a>
}
4 If the function g might depend on status flags set as a side effect of the first x + 1, or if the second
x + 1 might depend on control modes set as a side effect of the call to function g, then the program shall
- contain an appropriately placed invocation of #pragma STDC FENV_ACCESS ON.211)
+ contain an appropriately placed invocation of #pragma STDC FENV_ACCESS ON.<sup><a href="#note211"><b>211)</b></a></sup>
<a name="7.6.2" href="#7.6.2"><b> 7.6.2 Floating-point exceptions</b></a>
-1 The following functions provide access to the floating-point status flags.212) The int
+1 The following functions provide access to the floating-point status flags.<sup><a href="#note212"><b>212)</b></a></sup> The int
input argument for the functions represents a subset of floating-point exceptions, and can
be zero or the bitwise OR of one or more floating-point exception macros, for example
FE_OVERFLOW | FE_INEXACT. For other argument values the behavior of these
functions is undefined.
<a name="7.6.2.1" href="#7.6.2.1"><b> 7.6.2.1 The feclearexcept function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.6"><fenv.h></a>
int feclearexcept(int excepts);
- Description
+<b> Description</b>
2 The feclearexcept function attempts to clear the supported floating-point exceptions
represented by its argument.
- Returns
+<b> Returns</b>
3 The feclearexcept function returns zero if the excepts argument is zero or if all
the specified exceptions were successfully cleared. Otherwise, it returns a nonzero value.
- 211) The side effects impose a temporal ordering that requires two evaluations of x + 1. On the other
+ <sup><a name="note211" href="#note211"><b>211)</b></a></sup> The side effects impose a temporal ordering that requires two evaluations of x + 1. On the other
hand, without the #pragma STDC FENV_ACCESS ON pragma, and assuming the default state is
''off'', just one evaluation of x + 1 would suffice.
- 212) The functions fetestexcept, feraiseexcept, and feclearexcept support the basic
+ <sup><a name="note212" href="#note212"><b>212)</b></a></sup> The functions fetestexcept, feraiseexcept, and feclearexcept support the basic
abstraction of flags that are either set or clear. An implementation may endow floating-point status
flags with more information -- for example, the address of the code which first raised the floating-
point exception; the functions fegetexceptflag and fesetexceptflag deal with the full
content of flags.
-[<a name="
#p208" href="p208">page 208</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p208" href="#p208">page 208</a>] (<a href="#Contents">Contents</a>)
<a name="7.6.2.2" href="#7.6.2.2"><b> 7.6.2.2 The fegetexceptflag function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.6"><fenv.h></a>
int fegetexceptflag(fexcept_t *flagp,
int excepts);
- Description
+<b> Description</b>
2 The fegetexceptflag function attempts to store an implementation-defined
representation of the states of the floating-point status flags indicated by the argument
excepts in the object pointed to by the argument flagp.
- Returns
+<b> Returns</b>
3 The fegetexceptflag function returns zero if the representation was successfully
stored. Otherwise, it returns a nonzero value.
<a name="7.6.2.3" href="#7.6.2.3"><b> 7.6.2.3 The feraiseexcept function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.6"><fenv.h></a>
int feraiseexcept(int excepts);
- Description
+<b> Description</b>
2 The feraiseexcept function attempts to raise the supported floating-point exceptions
- represented by its argument.213) The order in which these floating-point exceptions are
+ represented by its argument.<sup><a href="#note213"><b>213)</b></a></sup> The order in which these floating-point exceptions are
raised is unspecified, except as stated in <a href="#F.8.6">F.8.6</a>. Whether the feraiseexcept function
additionally raises the ''inexact'' floating-point exception whenever it raises the
''overflow'' or ''underflow'' floating-point exception is implementation-defined.
- Returns
+<b> Returns</b>
3 The feraiseexcept function returns zero if the excepts argument is zero or if all
the specified exceptions were successfully raised. Otherwise, it returns a nonzero value.
- 213) The effect is intended to be similar to that of floating-point exceptions raised by arithmetic operations.
+ <sup><a name="note213" href="#note213"><b>213)</b></a></sup> The effect is intended to be similar to that of floating-point exceptions raised by arithmetic operations.
Hence, enabled traps for floating-point exceptions raised by this function are taken. The specification
in <a href="#F.8.6">F.8.6</a> is in the same spirit.
-[<a name="
#p209" href="p209">page 209</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p209" href="#p209">page 209</a>] (<a href="#Contents">Contents</a>)
<a name="7.6.2.4" href="#7.6.2.4"><b> 7.6.2.4 The fesetexceptflag function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.6"><fenv.h></a>
int fesetexceptflag(const fexcept_t *flagp,
int excepts);
- Description
+<b> Description</b>
2 The fesetexceptflag function attempts to set the floating-point status flags
indicated by the argument excepts to the states stored in the object pointed to by
flagp. The value of *flagp shall have been set by a previous call to
fegetexceptflag whose second argument represented at least those floating-point
exceptions represented by the argument excepts. This function does not raise floating-
point exceptions, but only sets the state of the flags.
- Returns
+<b> Returns</b>
3 The fesetexceptflag function returns zero if the excepts argument is zero or if
all the specified flags were successfully set to the appropriate state. Otherwise, it returns
a nonzero value.
<a name="7.6.2.5" href="#7.6.2.5"><b> 7.6.2.5 The fetestexcept function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.6"><fenv.h></a>
int fetestexcept(int excepts);
- Description
+<b> Description</b>
2 The fetestexcept function determines which of a specified subset of the floating-
point exception flags are currently set. The excepts argument specifies the floating-
- point status flags to be queried.214)
- Returns
+ point status flags to be queried.<sup><a href="#note214"><b>214)</b></a></sup>
+<b> Returns</b>
3 The fetestexcept function returns the value of the bitwise OR of the floating-point
exception macros corresponding to the currently set floating-point exceptions included in
excepts.
- 214) This mechanism allows testing several floating-point exceptions with just one function call.
+ <sup><a name="note214" href="#note214"><b>214)</b></a></sup> This mechanism allows testing several floating-point exceptions with just one function call.
-[<a name="
#p210" href="p210">page 210</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p210" href="#p210">page 210</a>] (<a href="#Contents">Contents</a>)
#include <a href="#7.6"><fenv.h></a>
/* ... */
1 The fegetround and fesetround functions provide control of rounding direction
modes.
<a name="7.6.3.1" href="#7.6.3.1"><b> 7.6.3.1 The fegetround function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.6"><fenv.h></a>
int fegetround(void);
- Description
+<b> Description</b>
2 The fegetround function gets the current rounding direction.
- Returns
+<b> Returns</b>
3 The fegetround function returns the value of the rounding direction macro
representing the current rounding direction or a negative value if there is no such
rounding direction macro or the current rounding direction is not determinable.
<a name="7.6.3.2" href="#7.6.3.2"><b> 7.6.3.2 The fesetround function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.6"><fenv.h></a>
int fesetround(int round);
- Description
+<b> Description</b>
2 The fesetround function establishes the rounding direction represented by its
argument round. If the argument is not equal to the value of a rounding direction macro,
the rounding direction is not changed.
- Returns
+<b> Returns</b>
3 The fesetround function returns zero if and only if the requested rounding direction
was established.
-
-[<a name="#p211" href="p211">page 211</a>] (<a href="#Contents">Contents</a>)
+[<a name="p211" href="#p211">page 211</a>] (<a href="#Contents">Contents</a>)
4 EXAMPLE Save, set, and restore the rounding direction. Report an error and abort if setting the
rounding direction fails.
1 The functions in this section manage the floating-point environment -- status flags and
control modes -- as one entity.
<a name="7.6.4.1" href="#7.6.4.1"><b> 7.6.4.1 The fegetenv function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.6"><fenv.h></a>
int fegetenv(fenv_t *envp);
- Description
+<b> Description</b>
2 The fegetenv function attempts to store the current floating-point environment in the
object pointed to by envp.
- Returns
+<b> Returns</b>
3 The fegetenv function returns zero if the environment was successfully stored.
Otherwise, it returns a nonzero value.
<a name="7.6.4.2" href="#7.6.4.2"><b> 7.6.4.2 The feholdexcept function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.6"><fenv.h></a>
int feholdexcept(fenv_t *envp);
- Description
+<b> Description</b>
2 The feholdexcept function saves the current floating-point environment in the object
pointed to by envp, clears the floating-point status flags, and then installs a non-stop
(continue on floating-point exceptions) mode, if available, for all floating-point
- exceptions.215)
+ exceptions.<sup><a href="#note215"><b>215)</b></a></sup>
-[<a name="
#p212" href="p212">page 212</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p212" href="#p212">page 212</a>] (<a href="#Contents">Contents</a>)
- Returns
+<b> Returns</b>
3 The feholdexcept function returns zero if and only if non-stop floating-point
exception handling was successfully installed.
<a name="7.6.4.3" href="#7.6.4.3"><b> 7.6.4.3 The fesetenv function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.6"><fenv.h></a>
int fesetenv(const fenv_t *envp);
- Description
+<b> Description</b>
2 The fesetenv function attempts to establish the floating-point environment represented
by the object pointed to by envp. The argument envp shall point to an object set by a
call to fegetenv or feholdexcept, or equal a floating-point environment macro.
Note that fesetenv merely installs the state of the floating-point status flags
represented through its argument, and does not raise these floating-point exceptions.
- Returns
+<b> Returns</b>
3 The fesetenv function returns zero if the environment was successfully established.
Otherwise, it returns a nonzero value.
<a name="7.6.4.4" href="#7.6.4.4"><b> 7.6.4.4 The feupdateenv function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.6"><fenv.h></a>
int feupdateenv(const fenv_t *envp);
- Description
+<b> Description</b>
2 The feupdateenv function attempts to save the currently raised floating-point
exceptions in its automatic storage, install the floating-point environment represented by
the object pointed to by envp, and then raise the saved floating-point exceptions. The
argument envp shall point to an object set by a call to feholdexcept or fegetenv,
or equal a floating-point environment macro.
- Returns
+<b> Returns</b>
3 The feupdateenv function returns zero if all the actions were successfully carried out.
Otherwise, it returns a nonzero value.
- 215) IEC 60559 systems have a default non-stop mode, and typically at least one other mode for trap
+ <sup><a name="note215" href="#note215"><b>215)</b></a></sup> IEC 60559 systems have a default non-stop mode, and typically at least one other mode for trap
handling or aborting; if the system provides only the non-stop mode then installing it is trivial. For
such systems, the feholdexcept function can be used in conjunction with the feupdateenv
function to write routines that hide spurious floating-point exceptions from their callers.
-[<a name="
#p213" href="p213">page 213</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p213" href="#p213">page 213</a>] (<a href="#Contents">Contents</a>)
4 EXAMPLE Hide spurious underflow floating-point exceptions:
#include <a href="#7.6"><fenv.h></a>
return result;
}
-
-
-
-[<a name="#p214" href="p214">page 214</a>] (<a href="#Contents">Contents</a>)
+[<a name="p214" href="#p214">page 214</a>] (<a href="#Contents">Contents</a>)
<a name="7.7" href="#7.7"><b> 7.7 Characteristics of floating types <float.h></b></a>
1 The header <a href="#7.7"><float.h></a> defines several macros that expand to various limits and
2 The macros, their meanings, and the constraints (or restrictions) on their values are listed
in <a href="#5.2.4.2.2">5.2.4.2.2</a>.
-
-
-
-[<a name="#p215" href="p215">page 215</a>] (<a href="#Contents">Contents</a>)
+[<a name="p215" href="#p215">page 215</a>] (<a href="#Contents">Contents</a>)
<a name="7.8" href="#7.8"><b> 7.8 Format conversion of integer types <inttypes.h></b></a>
1 The header <a href="#7.8"><inttypes.h></a> includes the header <a href="#7.20"><stdint.h></a> and extends it with
imaxdiv_t
which is a structure type that is the type of the value returned by the imaxdiv function.
For each type declared in <a href="#7.20"><stdint.h></a>, it defines corresponding macros for conversion
- specifiers for use with the formatted input/output functions.216)
+ specifiers for use with the formatted input/output functions.<sup><a href="#note216"><b>216)</b></a></sup>
Forward references: integer types <a href="#7.20"><stdint.h></a> (<a href="#7.20">7.20</a>), formatted input/output
functions (<a href="#7.21.6">7.21.6</a>), formatted wide character input/output functions (<a href="#7.28.2">7.28.2</a>).
<a name="7.8.1" href="#7.8.1"><b> 7.8.1 Macros for format specifiers</b></a>
format argument of a formatted input/output function when converting the corresponding
integer type. These macro names have the general form of PRI (character string literals
for the fprintf and fwprintf family) or SCN (character string literals for the
- fscanf and fwscanf family),217) followed by the conversion specifier, followed by a
+ fscanf and fwscanf family),<sup><a href="#note217"><b>217)</b></a></sup> followed by the conversion specifier, followed by a
name corresponding to a similar type name in <a href="#7.20.1">7.20.1</a>. In these names, N represents the
width of the type as described in <a href="#7.20.1">7.20.1</a>. For example, PRIdFAST32 can be used in a
format string to print the value of an integer of type int_fast32_t.
-
216) See ''future library directions'' (<a href="#7.30.4">7.30.4</a>).
- 217) Separate macros are given for use with fprintf and fscanf functions because, in the general case,
+
<sup><a name="note216" href="#note216"><b>216)</b></a></sup> See ''future library directions'' (<a href="#7.30.4">7.30.4</a>).
+ <sup><a name="note217" href="#note217"><b>217)</b></a></sup> Separate macros are given for use with fprintf and fscanf functions because, in the general case,
different format specifiers may be required for fprintf and fscanf, even when the type is the
same.
-[<a name="
#p216" href="p216">page 216</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p216" href="#p216">page 216</a>] (<a href="#Contents">Contents</a>)
SCNdN SCNdLEASTN SCNdFASTN SCNdMAX SCNdPTR
SCNiN SCNiLEASTN SCNiFASTN SCNiMAX SCNiPTR
<a name="7.8.2" href="#7.8.2"><b> 7.8.2 Functions for greatest-width integer types</b></a>
<a name="7.8.2.1" href="#7.8.2.1"><b> 7.8.2.1 The imaxabs function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.8"><inttypes.h></a>
intmax_t imaxabs(intmax_t j);
- Description
+<b> Description</b>
2 The imaxabs function computes the absolute value of an integer j. If the result cannot
- be represented, the behavior is undefined.218)
- Returns
+ be represented, the behavior is undefined.<sup><a href="#note218"><b>218)</b></a></sup>
+<b> Returns</b>
3 The imaxabs function returns the absolute value.
- 218) The absolute value of the most negative number cannot be represented in two's complement.
+ <sup><a name="note218" href="#note218"><b>218)</b></a></sup> The absolute value of the most negative number cannot be represented in two's complement.
-[<a name="
#p217" href="p217">page 217</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p217" href="#p217">page 217</a>] (<a href="#Contents">Contents</a>)
<a name="7.8.2.2" href="#7.8.2.2"><b> 7.8.2.2 The imaxdiv function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.8"><inttypes.h></a>
imaxdiv_t imaxdiv(intmax_t numer, intmax_t denom);
- Description
+<b> Description</b>
2 The imaxdiv function computes numer / denom and numer % denom in a single
operation.
- Returns
+<b> Returns</b>
3 The imaxdiv function returns a structure of type imaxdiv_t comprising both the
quotient and the remainder. The structure shall contain (in either order) the members
quot (the quotient) and rem (the remainder), each of which has type intmax_t. If
either part of the result cannot be represented, the behavior is undefined.
<a name="7.8.2.3" href="#7.8.2.3"><b> 7.8.2.3 The strtoimax and strtoumax functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.8"><inttypes.h></a>
intmax_t strtoimax(const char * restrict nptr,
char ** restrict endptr, int base);
uintmax_t strtoumax(const char * restrict nptr,
char ** restrict endptr, int base);
- Description
+<b> Description</b>
2 The strtoimax and strtoumax functions are equivalent to the strtol, strtoll,
strtoul, and strtoull functions, except that the initial portion of the string is
converted to intmax_t and uintmax_t representation, respectively.
- Returns
+<b> Returns</b>
3 The strtoimax and strtoumax functions return the converted value, if any. If no
conversion could be performed, zero is returned. If the correct value is outside the range
of representable values, INTMAX_MAX, INTMAX_MIN, or UINTMAX_MAX is returned
Forward references: the strtol, strtoll, strtoul, and strtoull functions
(<a href="#7.22.1.4">7.22.1.4</a>).
-
-
-
-[<a name="#p218" href="p218">page 218</a>] (<a href="#Contents">Contents</a>)
+[<a name="p218" href="#p218">page 218</a>] (<a href="#Contents">Contents</a>)
<a name="7.8.2.4" href="#7.8.2.4"><b> 7.8.2.4 The wcstoimax and wcstoumax functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.19"><stddef.h></a> // for wchar_t
#include <a href="#7.8"><inttypes.h></a>
intmax_t wcstoimax(const wchar_t * restrict nptr,
wchar_t ** restrict endptr, int base);
uintmax_t wcstoumax(const wchar_t * restrict nptr,
wchar_t ** restrict endptr, int base);
- Description
+<b> Description</b>
2 The wcstoimax and wcstoumax functions are equivalent to the wcstol, wcstoll,
wcstoul, and wcstoull functions except that the initial portion of the wide string is
converted to intmax_t and uintmax_t representation, respectively.
- Returns
+<b> Returns</b>
3 The wcstoimax function returns the converted value, if any. If no conversion could be
performed, zero is returned. If the correct value is outside the range of representable
values, INTMAX_MAX, INTMAX_MIN, or UINTMAX_MAX is returned (according to the
Forward references: the wcstol, wcstoll, wcstoul, and wcstoull functions
(<a href="#7.28.4.1.2">7.28.4.1.2</a>).
-
-
-
-[<a name="#p219" href="p219">page 219</a>] (<a href="#Contents">Contents</a>)
+[<a name="p219" href="#p219">page 219</a>] (<a href="#Contents">Contents</a>)
<a name="7.9" href="#7.9"><b> 7.9 Alternative spellings <iso646.h></b></a>
1 The header <a href="#7.9"><iso646.h></a> defines the following eleven macros (on the left) that expand
xor ^
xor_eq ^=
-
-
-
-[<a name="#p220" href="p220">page 220</a>] (<a href="#Contents">Contents</a>)
+[<a name="p220" href="#p220">page 220</a>] (<a href="#Contents">Contents</a>)
<a name="7.10" href="#7.10"><b> 7.10 Sizes of integer types <limits.h></b></a>
1 The header <a href="#7.10"><limits.h></a> defines several macros that expand to various limits and
2 The macros, their meanings, and the constraints (or restrictions) on their values are listed
in <a href="#5.2.4.2.1">5.2.4.2.1</a>.
-
-
-
-[<a name="#p221" href="p221">page 221</a>] (<a href="#Contents">Contents</a>)
+[<a name="p221" href="#p221">page 221</a>] (<a href="#Contents">Contents</a>)
<a name="7.11" href="#7.11"><b> 7.11 Localization <locale.h></b></a>
1 The header <a href="#7.11"><locale.h></a> declares two functions, one type, and defines several macros.
char int_p_sign_posn; // CHAR_MAX
char int_n_sign_posn; // CHAR_MAX
-
-
-
-[<a name="#p222" href="p222">page 222</a>] (<a href="#Contents">Contents</a>)
+[<a name="p222" href="#p222">page 222</a>] (<a href="#Contents">Contents</a>)
3 The macros defined are NULL (described in <a href="#7.19">7.19</a>); and
LC_ALL
LC_NUMERIC
LC_TIME
which expand to integer constant expressions with distinct values, suitable for use as the
- first argument to the setlocale function.219) Additional macro definitions, beginning
- with the characters LC_ and an uppercase letter,220) may also be specified by the
+ first argument to the setlocale function.<sup><a href="#note219"><b>219)</b></a></sup> Additional macro definitions, beginning
+ with the characters LC_ and an uppercase letter,<sup><a href="#note220"><b>220)</b></a></sup> may also be specified by the
implementation.
<a name="7.11.1" href="#7.11.1"><b> 7.11.1 Locale control</b></a>
<a name="7.11.1.1" href="#7.11.1.1"><b> 7.11.1.1 The setlocale function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.11"><locale.h></a>
char *setlocale(int category, const char *locale);
- Description
+<b> Description</b>
2 The setlocale function selects the appropriate portion of the program's locale as
specified by the category and locale arguments. The setlocale function may be
used to change or query the program's entire current locale or portions thereof. The value
LC_ALL for category names the program's entire locale; the other values for
category name only a portion of the program's locale. LC_COLLATE affects the
behavior of the strcoll and strxfrm functions. LC_CTYPE affects the behavior of
- the character handling functions221) and the multibyte and wide character functions.
+ the character handling functions<sup><a href="#note221"><b>221)</b></a></sup> and the multibyte and wide character functions.
LC_MONETARY affects the monetary formatting information returned by the
localeconv function. LC_NUMERIC affects the decimal-point character for the
formatted input/output functions and the string conversion functions, as well as the
of "" for locale specifies the locale-specific native environment. Other
implementation-defined strings may be passed as the second argument to setlocale.
- 219) ISO/IEC 9945-2 specifies locale and charmap formats that may be used to specify locales for C.
-
220) See ''future library directions'' (<a href="#7.30.5">7.30.5</a>).
-
221) The only functions in <a href="#7.4">7.4</a> whose behavior is not affected by the current locale are isdigit and
+ <sup><a name="note219" href="#note219"><b>219)</b></a></sup> ISO/IEC 9945-2 specifies locale and charmap formats that may be used to specify locales for C.
+
<sup><a name="note220" href="#note220"><b>220)</b></a></sup> See ''future library directions'' (<a href="#7.30.5">7.30.5</a>).
+
<sup><a name="note221" href="#note221"><b>221)</b></a></sup> The only functions in <a href="#7.4">7.4</a> whose behavior is not affected by the current locale are isdigit and
isxdigit.
-[<a name="
#p223" href="p223">page 223</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p223" href="#p223">page 223</a>] (<a href="#Contents">Contents</a>)
4 At program startup, the equivalent of
setlocale(LC_ALL, "C");
5 A call to the setlocale function may introduce a data race with other calls to the
setlocale function or with calls to functions that are affected by the current locale.
The implementation shall behave as if no library function calls the setlocale function.
- Returns
+<b> Returns</b>
6 If a pointer to a string is given for locale and the selection can be honored, the
setlocale function returns a pointer to the string associated with the specified
category for the new locale. If the selection cannot be honored, the setlocale
function returns a null pointer and the program's locale is not changed.
7 A null pointer for locale causes the setlocale function to return a pointer to the
string associated with the category for the program's current locale; the program's
- locale is not changed.222)
+ locale is not changed.<sup><a href="#note222"><b>222)</b></a></sup>
8 The pointer to string returned by the setlocale function is such that a subsequent call
with that string value and its associated category will restore that part of the program's
locale. The string pointed to shall not be modified by the program, but may be
strftime function (<a href="#7.26.3.5">7.26.3.5</a>), the strxfrm function (<a href="#7.23.4.5">7.23.4.5</a>).
<a name="7.11.2" href="#7.11.2"><b> 7.11.2 Numeric formatting convention inquiry</b></a>
<a name="7.11.2.1" href="#7.11.2.1"><b> 7.11.2.1 The localeconv function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.11"><locale.h></a>
struct lconv *localeconv(void);
- Description
+<b> Description</b>
2 The localeconv function sets the components of an object with type struct lconv
with values appropriate for the formatting of numeric quantities (monetary and otherwise)
according to the rules of the current locale.
- 222) The implementation shall arrange to encode in a string the various categories due to a heterogeneous
+ <sup><a name="note222" href="#note222"><b>222)</b></a></sup> The implementation shall arrange to encode in a string the various categories due to a heterogeneous
locale when category has the value LC_ALL.
-[<a name="
#p224" href="p224">page 224</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p224" href="#p224">page 224</a>] (<a href="#Contents">Contents</a>)
3 The members of the structure with type char * are pointers to strings, any of which
(except decimal_point) can point to "", to indicate that the value is not available in
Set to 1 or 0 if the currency_symbol respectively precedes or
succeeds the value for a nonnegative locally formatted monetary quantity.
-
-
-[<a name="#p225" href="p225">page 225</a>] (<a href="#Contents">Contents</a>)
+[<a name="p225" href="#p225">page 225</a>] (<a href="#Contents">Contents</a>)
char n_cs_precedes
Set to 1 or 0 if the currency_symbol respectively precedes or
Set to a value indicating the separation of the int_curr_symbol, the
sign string, and the value for a nonnegative internationally formatted
monetary quantity.
-[<a name="#p226" href="p226">page 226</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p226" href="#p226">page 226</a>] (<a href="#Contents">Contents</a>)
char int_n_sep_by_space
Set to a value indicating the separation of the int_curr_symbol, the
3 The sign string immediately precedes the currency symbol.
4 The sign string immediately succeeds the currency symbol.
-
-[<a name="#p227" href="p227">page 227</a>] (<a href="#Contents">Contents</a>)
+[<a name="p227" href="#p227">page 227</a>] (<a href="#Contents">Contents</a>)
7 The implementation shall behave as if no library function calls the localeconv
function.
- Returns
+<b> Returns</b>
8 The localeconv function returns a pointer to the filled-in object. The structure
pointed to by the return value shall not be modified by the program, but may be
overwritten by a subsequent call to the localeconv function. In addition, calls to the
int_p_sign_posn 1 1 1 1
int_n_sign_posn 4 1 4 2
-
-
-
-[<a name="#p228" href="p228">page 228</a>] (<a href="#Contents">Contents</a>)
+[<a name="p228" href="#p228">page 228</a>] (<a href="#Contents">Contents</a>)
11 EXAMPLE 2 The following table illustrates how the cs_precedes, sep_by_space, and sign_posn members
affect the formatted value.
3 +$1.25 +$ <a href="#1.25">1.25</a> + $1.25
4 $+1.25 $+ <a href="#1.25">1.25</a> $ +1.25
-
-
-
-[<a name="#p229" href="p229">page 229</a>] (<a href="#Contents">Contents</a>)
+[<a name="p229" href="#p229">page 229</a>] (<a href="#Contents">Contents</a>)
<a name="7.12" href="#7.12"><b> 7.12 Mathematics <math.h></b></a>
1 The header <a href="#7.12"><math.h></a> declares two types and many mathematical functions and defines
several macros. Most synopses specify a family of functions consisting of a principal
function with one or more double parameters, a double return value, or both; and
other functions with the same name but with f and l suffixes, which are corresponding
- functions with float and long double parameters, return values, or both.223)
+ functions with float and long double parameters, return values, or both.<sup><a href="#note223"><b>223)</b></a></sup>
Integer arithmetic functions and conversion functions are discussed later.
2 The types
float_t
float_t and double_t are float and double, respectively; if
FLT_EVAL_METHOD equals 1, they are both double; if FLT_EVAL_METHOD equals
2, they are both long double; and for other values of FLT_EVAL_METHOD, they are
- otherwise implementation-defined.224)
+ otherwise implementation-defined.<sup><a href="#note224"><b>224)</b></a></sup>
3 The macro
HUGE_VAL
expands to a positive double constant expression, not necessarily representable as a
float. The macros
HUGE_VALF
HUGE_VALL
- are respectively float and long double analogs of HUGE_VAL.225)
+ are respectively float and long double analogs of HUGE_VAL.<sup><a href="#note225"><b>225)</b></a></sup>
4 The macro
INFINITY
expands to a constant expression of type float representing positive or unsigned
-
223) Particularly on systems with wide expression evaluation, a <a href="#7.12"><math.h></a> function might pass arguments
+
<sup><a name="note223" href="#note223"><b>223)</b></a></sup> Particularly on systems with wide expression evaluation, a <a href="#7.12"><math.h></a> function might pass arguments
and return values in wider format than the synopsis prototype indicates.
- 224) The types float_t and double_t are intended to be the implementation's most efficient types at
+ <sup><a name="note224" href="#note224"><b>224)</b></a></sup> The types float_t and double_t are intended to be the implementation's most efficient types at
least as wide as float and double, respectively. For FLT_EVAL_METHOD equal 0, 1, or 2, the
type float_t is the narrowest type used by the implementation to evaluate floating expressions.
- 225) HUGE_VAL, HUGE_VALF, and HUGE_VALL can be positive infinities in an implementation that
+ <sup><a name="note225" href="#note225"><b>225)</b></a></sup> HUGE_VAL, HUGE_VALF, and HUGE_VALL can be positive infinities in an implementation that
supports infinities.
-[<a name="
#p230" href="p230">page 230</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p230" href="#p230">page 230</a>] (<a href="#Contents">Contents</a>)
- translation time.226)
+ translation time.<sup><a href="#note226"><b>226)</b></a></sup>
5 The macro
NAN
is defined if and only if the implementation supports quiet NaNs for the float type. It
7 The macro
FP_FAST_FMA
is optionally defined. If defined, it indicates that the fma function generally executes
- about as fast as, or faster than, a multiply and an add of double operands.227) The
+ about as fast as, or faster than, a multiply and an add of double operands.<sup><a href="#note227"><b>227)</b></a></sup> The
macros
FP_FAST_FMAF
FP_FAST_FMAL
-INT_MAX. The value of FP_ILOGBNAN shall be either INT_MAX or INT_MIN.
-
226) In this case, using INFINITY will violate the constraint in <a href="#6.4.4">6.4.4</a> and thus require a diagnostic.
- 227) Typically, the FP_FAST_FMA macro is defined if and only if the fma function is implemented
+
<sup><a name="note226" href="#note226"><b>226)</b></a></sup> In this case, using INFINITY will violate the constraint in <a href="#6.4.4">6.4.4</a> and thus require a diagnostic.
+ <sup><a name="note227" href="#note227"><b>227)</b></a></sup> Typically, the FP_FAST_FMA macro is defined if and only if the fma function is implemented
directly with a hardware multiply-add instruction. Software implementations are expected to be
substantially slower.
-[<a name="
#p231" href="p231">page 231</a>] (<a href="#Contents">Contents</a>)
+[<a name="
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9 The macros
MATH_ERRNO
2 For all functions, a domain error occurs if an input argument is outside the domain over
which the mathematical function is defined. The description of each function lists any
required domain errors; an implementation may define additional domain errors, provided
- that such errors are consistent with the mathematical definition of the function.228) On a
+ that such errors are consistent with the mathematical definition of the function.<sup><a href="#note228"><b>228)</b></a></sup> On a
domain error, the function returns an implementation-defined value; if the integer
expression math_errhandling & MATH_ERRNO is nonzero, the integer expression
errno acquires the value EDOM; if the integer expression math_errhandling &
error, the function returns an implementation-defined value; if the integer expression
- 228) In an implementation that supports infinities, this allows an infinity as an argument to be a domain
+ <sup><a name="note228" href="#note228"><b>228)</b></a></sup> In an implementation that supports infinities, this allows an infinity as an argument to be a domain
error if the mathematical domain of the function does not include the infinity.
-[<a name="
#p232" href="p232">page 232</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p232" href="#p232">page 232</a>] (<a href="#Contents">Contents</a>)
math_errhandling & MATH_ERRNO is nonzero, the integer expression errno
acquires the value ERANGE; if the integer expression math_errhandling &
point exception is raised.
6 The result underflows if the magnitude of the mathematical result is so small that the
mathematical result cannot be represented, without extraordinary roundoff error, in an
- object of the specified type.229) If the result underflows, the function returns an
+ object of the specified type.<sup><a href="#note229"><b>229)</b></a></sup> If the result underflows, the function returns an
implementation-defined value whose magnitude is no greater than the smallest
normalized positive number in the specified type; if the integer expression
math_errhandling & MATH_ERRNO is nonzero, whether errno acquires the
math_errhandling & MATH_ERREXCEPT is nonzero, whether the ''underflow''
floating-point exception is raised is implementation-defined.
7 If a domain, pole, or range error occurs and the integer expression
- math_errhandling & MATH_ERRNO is zero,230) then errno shall either be set to
+ math_errhandling & MATH_ERRNO is zero,<sup><a href="#note230"><b>230)</b></a></sup> then errno shall either be set to
the value corresponding to the error or left unmodified. If no such error occurs, errno
shall be left unmodified regardless of the setting of math_errhandling.
- 229) The term underflow here is intended to encompass both ''gradual underflow'' as in IEC 60559 and
+ <sup><a name="note229" href="#note229"><b>229)</b></a></sup> The term underflow here is intended to encompass both ''gradual underflow'' as in IEC 60559 and
also ''flush-to-zero'' underflow.
- 230) Math errors are being indicated by the floating-point exception flags rather than by errno.
+ <sup><a name="note230" href="#note230"><b>230)</b></a></sup> Math errors are being indicated by the floating-point exception flags rather than by errno.
-[<a name="
#p233" href="p233">page 233</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p233" href="#p233">page 233</a>] (<a href="#Contents">Contents</a>)
<a name="7.12.2" href="#7.12.2"><b> 7.12.2 The FP_CONTRACT pragma</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
#pragma STDC FP_CONTRACT on-off-switch
- Description
+<b> Description</b>
2 The FP_CONTRACT pragma can be used to allow (if the state is ''on'') or disallow (if the
state is ''off'') the implementation to contract expressions (<a href="#6.5">6.5</a>). Each pragma can occur
either outside external declarations or preceding all explicit declarations and statements
1 In the synopses in this subclause, real-floating indicates that the argument shall be an
expression of real floating type.
<a name="7.12.3.1" href="#7.12.3.1"><b> 7.12.3.1 The fpclassify macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int fpclassify(real-floating x);
- Description
+<b> Description</b>
2 The fpclassify macro classifies its argument value as NaN, infinite, normal,
subnormal, zero, or into another implementation-defined category. First, an argument
represented in a format wider than its semantic type is converted to its semantic type.
- Then classification is based on the type of the argument.231)
- Returns
+ Then classification is based on the type of the argument.<sup><a href="#note231"><b>231)</b></a></sup>
+<b> Returns</b>
3 The fpclassify macro returns the value of the number classification macro
appropriate to the value of its argument. *
- 231) Since an expression can be evaluated with more range and precision than its type has, it is important to
+ <sup><a name="note231" href="#note231"><b>231)</b></a></sup> Since an expression can be evaluated with more range and precision than its type has, it is important to
know the type that classification is based on. For example, a normal long double value might
become subnormal when converted to double, and zero when converted to float.
-[<a name="
#p234" href="p234">page 234</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p234" href="#p234">page 234</a>] (<a href="#Contents">Contents</a>)
<a name="7.12.3.2" href="#7.12.3.2"><b> 7.12.3.2 The isfinite macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int isfinite(real-floating x);
- Description
+<b> Description</b>
2 The isfinite macro determines whether its argument has a finite value (zero,
subnormal, or normal, and not infinite or NaN). First, an argument represented in a
format wider than its semantic type is converted to its semantic type. Then determination
is based on the type of the argument.
- Returns
+<b> Returns</b>
3 The isfinite macro returns a nonzero value if and only if its argument has a finite
value.
<a name="7.12.3.3" href="#7.12.3.3"><b> 7.12.3.3 The isinf macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int isinf(real-floating x);
- Description
+<b> Description</b>
2 The isinf macro determines whether its argument value is an infinity (positive or
negative). First, an argument represented in a format wider than its semantic type is
converted to its semantic type. Then determination is based on the type of the argument.
- Returns
+<b> Returns</b>
3 The isinf macro returns a nonzero value if and only if its argument has an infinite
value.
<a name="7.12.3.4" href="#7.12.3.4"><b> 7.12.3.4 The isnan macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int isnan(real-floating x);
- Description
+<b> Description</b>
2 The isnan macro determines whether its argument value is a NaN. First, an argument
represented in a format wider than its semantic type is converted to its semantic type.
- Then determination is based on the type of the argument.232)
+ Then determination is based on the type of the argument.<sup><a href="#note232"><b>232)</b></a></sup>
- 232) For the isnan macro, the type for determination does not matter unless the implementation supports
+ <sup><a name="note232" href="#note232"><b>232)</b></a></sup> For the isnan macro, the type for determination does not matter unless the implementation supports
NaNs in the evaluation type but not in the semantic type.
-[<a name="
#p235" href="p235">page 235</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p235" href="#p235">page 235</a>] (<a href="#Contents">Contents</a>)
- Returns
+<b> Returns</b>
3 The isnan macro returns a nonzero value if and only if its argument has a NaN value.
<a name="7.12.3.5" href="#7.12.3.5"><b> 7.12.3.5 The isnormal macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int isnormal(real-floating x);
- Description
+<b> Description</b>
2 The isnormal macro determines whether its argument value is normal (neither zero,
subnormal, infinite, nor NaN). First, an argument represented in a format wider than its
semantic type is converted to its semantic type. Then determination is based on the type
of the argument.
- Returns
+<b> Returns</b>
3 The isnormal macro returns a nonzero value if and only if its argument has a normal
value.
<a name="7.12.3.6" href="#7.12.3.6"><b> 7.12.3.6 The signbit macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int signbit(real-floating x);
- Description
-2 The signbit macro determines whether the sign of its argument value is negative.233)
- Returns
+<b> Description</b>
+2 The signbit macro determines whether the sign of its argument value is negative.<sup><a href="#note233"><b>233)</b></a></sup>
+<b> Returns</b>
3 The signbit macro returns a nonzero value if and only if the sign of its argument value
is negative.
- 233) The signbit macro reports the sign of all values, including infinities, zeros, and NaNs. If zero is
+ <sup><a name="note233" href="#note233"><b>233)</b></a></sup> The signbit macro reports the sign of all values, including infinities, zeros, and NaNs. If zero is
unsigned, it is treated as positive.
-[<a name="
#p236" href="p236">page 236</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p236" href="#p236">page 236</a>] (<a href="#Contents">Contents</a>)
<a name="7.12.4" href="#7.12.4"><b> 7.12.4 Trigonometric functions</b></a>
<a name="7.12.4.1" href="#7.12.4.1"><b> 7.12.4.1 The acos functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double acos(double x);
float acosf(float x);
long double acosl(long double x);
- Description
+<b> Description</b>
2 The acos functions compute the principal value of the arc cosine of x. A domain error
occurs for arguments not in the interval [-1, +1].
- Returns
+<b> Returns</b>
3 The acos functions return arccos x in the interval [0, pi ] radians.
<a name="7.12.4.2" href="#7.12.4.2"><b> 7.12.4.2 The asin functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double asin(double x);
float asinf(float x);
long double asinl(long double x);
- Description
+<b> Description</b>
2 The asin functions compute the principal value of the arc sine of x. A domain error
occurs for arguments not in the interval [-1, +1].
- Returns
+<b> Returns</b>
3 The asin functions return arcsin x in the interval [-pi /2, +pi /2] radians.
<a name="7.12.4.3" href="#7.12.4.3"><b> 7.12.4.3 The atan functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double atan(double x);
float atanf(float x);
long double atanl(long double x);
- Description
+<b> Description</b>
2 The atan functions compute the principal value of the arc tangent of x.
+[<a name="p237" href="#p237">page 237</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p237" href="p237">page 237</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The atan functions return arctan x in the interval [-pi /2, +pi /2] radians.
<a name="7.12.4.4" href="#7.12.4.4"><b> 7.12.4.4 The atan2 functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double atan2(double y, double x);
float atan2f(float y, float x);
long double atan2l(long double y, long double x);
- Description
+<b> Description</b>
2 The atan2 functions compute the value of the arc tangent of y/x, using the signs of both
arguments to determine the quadrant of the return value. A domain error may occur if
both arguments are zero.
- Returns
+<b> Returns</b>
3 The atan2 functions return arctan y/x in the interval [-pi , +pi ] radians.
<a name="7.12.4.5" href="#7.12.4.5"><b> 7.12.4.5 The cos functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double cos(double x);
float cosf(float x);
long double cosl(long double x);
- Description
+<b> Description</b>
2 The cos functions compute the cosine of x (measured in radians).
- Returns
+<b> Returns</b>
3 The cos functions return cos x.
<a name="7.12.4.6" href="#7.12.4.6"><b> 7.12.4.6 The sin functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double sin(double x);
float sinf(float x);
long double sinl(long double x);
- Description
+<b> Description</b>
2 The sin functions compute the sine of x (measured in radians).
+[<a name="p238" href="#p238">page 238</a>] (<a href="#Contents">Contents</a>)
-
-[<a name="#p238" href="p238">page 238</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The sin functions return sin x.
<a name="7.12.4.7" href="#7.12.4.7"><b> 7.12.4.7 The tan functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double tan(double x);
float tanf(float x);
long double tanl(long double x);
- Description
+<b> Description</b>
2 The tan functions return the tangent of x (measured in radians).
- Returns
+<b> Returns</b>
3 The tan functions return tan x.
<a name="7.12.5" href="#7.12.5"><b> 7.12.5 Hyperbolic functions</b></a>
<a name="7.12.5.1" href="#7.12.5.1"><b> 7.12.5.1 The acosh functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double acosh(double x);
float acoshf(float x);
long double acoshl(long double x);
- Description
+<b> Description</b>
2 The acosh functions compute the (nonnegative) arc hyperbolic cosine of x. A domain
error occurs for arguments less than 1.
- Returns
+<b> Returns</b>
3 The acosh functions return arcosh x in the interval [0, +(inf)].
<a name="7.12.5.2" href="#7.12.5.2"><b> 7.12.5.2 The asinh functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double asinh(double x);
float asinhf(float x);
long double asinhl(long double x);
- Description
+<b> Description</b>
2 The asinh functions compute the arc hyperbolic sine of x.
+[<a name="p239" href="#p239">page 239</a>] (<a href="#Contents">Contents</a>)
-[<a name="#p239" href="p239">page 239</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The asinh functions return arsinh x.
<a name="7.12.5.3" href="#7.12.5.3"><b> 7.12.5.3 The atanh functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double atanh(double x);
float atanhf(float x);
long double atanhl(long double x);
- Description
+<b> Description</b>
2 The atanh functions compute the arc hyperbolic tangent of x. A domain error occurs
for arguments not in the interval [-1, +1]. A pole error may occur if the argument equals
-1 or +1.
- Returns
+<b> Returns</b>
3 The atanh functions return artanh x.
<a name="7.12.5.4" href="#7.12.5.4"><b> 7.12.5.4 The cosh functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double cosh(double x);
float coshf(float x);
long double coshl(long double x);
- Description
+<b> Description</b>
2 The cosh functions compute the hyperbolic cosine of x. A range error occurs if the
magnitude of x is too large.
- Returns
+<b> Returns</b>
3 The cosh functions return cosh x.
<a name="7.12.5.5" href="#7.12.5.5"><b> 7.12.5.5 The sinh functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double sinh(double x);
float sinhf(float x);
long double sinhl(long double x);
- Description
+<b> Description</b>
2 The sinh functions compute the hyperbolic sine of x. A range error occurs if the
magnitude of x is too large.
-[<a name="#p240" href="p240">page 240</a>] (<a href="#Contents">Contents</a>)
- Returns
+[<a name="p240" href="#p240">page 240</a>] (<a href="#Contents">Contents</a>)
+
+<b> Returns</b>
3 The sinh functions return sinh x.
<a name="7.12.5.6" href="#7.12.5.6"><b> 7.12.5.6 The tanh functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double tanh(double x);
float tanhf(float x);
long double tanhl(long double x);
- Description
+<b> Description</b>
2 The tanh functions compute the hyperbolic tangent of x.
- Returns
+<b> Returns</b>
3 The tanh functions return tanh x.
<a name="7.12.6" href="#7.12.6"><b> 7.12.6 Exponential and logarithmic functions</b></a>
<a name="7.12.6.1" href="#7.12.6.1"><b> 7.12.6.1 The exp functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double exp(double x);
float expf(float x);
long double expl(long double x);
- Description
+<b> Description</b>
2 The exp functions compute the base-e exponential of x. A range error occurs if the
magnitude of x is too large.
- Returns
+<b> Returns</b>
3 The exp functions return ex .
<a name="7.12.6.2" href="#7.12.6.2"><b> 7.12.6.2 The exp2 functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double exp2(double x);
float exp2f(float x);
long double exp2l(long double x);
- Description
+<b> Description</b>
2 The exp2 functions compute the base-2 exponential of x. A range error occurs if the
magnitude of x is too large.
-[<a name="
#p241" href="p241">page 241</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p241" href="#p241">page 241</a>] (<a href="#Contents">Contents</a>)
- Returns
+<b> Returns</b>
3 The exp2 functions return 2x .
<a name="7.12.6.3" href="#7.12.6.3"><b> 7.12.6.3 The expm1 functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double expm1(double x);
float expm1f(float x);
long double expm1l(long double x);
- Description
+<b> Description</b>
2 The expm1 functions compute the base-e exponential of the argument, minus 1. A range
- error occurs if x is too large.234)
- Returns
+ error occurs if x is too large.<sup><a href="#note234"><b>234)</b></a></sup>
+<b> Returns</b>
3 The expm1 functions return ex - 1.
<a name="7.12.6.4" href="#7.12.6.4"><b> 7.12.6.4 The frexp functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double frexp(double value, int *exp);
float frexpf(float value, int *exp);
long double frexpl(long double value, int *exp);
- Description
+<b> Description</b>
2 The frexp functions break a floating-point number into a normalized fraction and an
integral power of 2. They store the integer in the int object pointed to by exp.
- Returns
+<b> Returns</b>
3 If value is not a floating-point number or if the integral power of 2 is outside the range
of int, the results are unspecified. Otherwise, the frexp functions return the value x,
such that x has a magnitude in the interval [1/2, 1) or zero, and value equals x x 2*exp .
- 234) For small magnitude x, expm1(x) is expected to be more accurate than exp(x) - 1.
+ <sup><a name="note234" href="#note234"><b>234)</b></a></sup> For small magnitude x, expm1(x) is expected to be more accurate than exp(x) - 1.
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<a name="7.12.6.5" href="#7.12.6.5"><b> 7.12.6.5 The ilogb functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int ilogb(double x);
int ilogbf(float x);
int ilogbl(long double x);
- Description
+<b> Description</b>
2 The ilogb functions extract the exponent of x as a signed int value. If x is zero they
compute the value FP_ILOGB0; if x is infinite they compute the value INT_MAX; if x is
a NaN they compute the value FP_ILOGBNAN; otherwise, they are equivalent to calling
the corresponding logb function and casting the returned value to type int. A domain
error or range error may occur if x is zero, infinite, or NaN. If the correct value is outside
the range of the return type, the numeric result is unspecified.
- Returns
+<b> Returns</b>
3 The ilogb functions return the exponent of x as a signed int value.
Forward references: the logb functions (<a href="#7.12.6.11">7.12.6.11</a>).
<a name="7.12.6.6" href="#7.12.6.6"><b> 7.12.6.6 The ldexp functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double ldexp(double x, int exp);
float ldexpf(float x, int exp);
long double ldexpl(long double x, int exp);
- Description
+<b> Description</b>
2 The ldexp functions multiply a floating-point number by an integral power of 2. A
range error may occur.
- Returns
+<b> Returns</b>
3 The ldexp functions return x x 2exp .
<a name="7.12.6.7" href="#7.12.6.7"><b> 7.12.6.7 The log functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double log(double x);
float logf(float x);
long double logl(long double x);
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-
-[<a name="#p243" href="p243">page 243</a>] (<a href="#Contents">Contents</a>)
-
- Description
+<b> Description</b>
2 The log functions compute the base-e (natural) logarithm of x. A domain error occurs if
the argument is negative. A pole error may occur if the argument is zero.
- Returns
+<b> Returns</b>
3 The log functions return loge x.
<a name="7.12.6.8" href="#7.12.6.8"><b> 7.12.6.8 The log10 functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double log10(double x);
float log10f(float x);
long double log10l(long double x);
- Description
+<b> Description</b>
2 The log10 functions compute the base-10 (common) logarithm of x. A domain error
occurs if the argument is negative. A pole error may occur if the argument is zero.
- Returns
+<b> Returns</b>
3 The log10 functions return log10 x.
<a name="7.12.6.9" href="#7.12.6.9"><b> 7.12.6.9 The log1p functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double log1p(double x);
float log1pf(float x);
long double log1pl(long double x);
- Description
-2 The log1p functions compute the base-e (natural) logarithm of 1 plus the argument.235)
+<b> Description</b>
+2 The log1p functions compute the base-e (natural) logarithm of 1 plus the argument.<sup><a href="#note235"><b>235)</b></a></sup>
A domain error occurs if the argument is less than -1. A pole error may occur if the
argument equals -1.
- Returns
+<b> Returns</b>
3 The log1p functions return loge (1 + x).
- 235) For small magnitude x, log1p(x) is expected to be more accurate than log(1 + x).
+ <sup><a name="note235" href="#note235"><b>235)</b></a></sup> For small magnitude x, log1p(x) is expected to be more accurate than log(1 + x).
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<a name="7.12.6.10" href="#7.12.6.10"><b> 7.12.6.10 The log2 functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double log2(double x);
float log2f(float x);
long double log2l(long double x);
- Description
+<b> Description</b>
2 The log2 functions compute the base-2 logarithm of x. A domain error occurs if the
argument is less than zero. A pole error may occur if the argument is zero.
- Returns
+<b> Returns</b>
3 The log2 functions return log2 x.
<a name="7.12.6.11" href="#7.12.6.11"><b> 7.12.6.11 The logb functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double logb(double x);
float logbf(float x);
long double logbl(long double x);
- Description
+<b> Description</b>
2 The logb functions extract the exponent of x, as a signed integer value in floating-point
format. If x is subnormal it is treated as though it were normalized; thus, for positive
finite x,
1 <= x x FLT_RADIX-logb(x) < FLT_RADIX
A domain error or pole error may occur if the argument is zero.
- Returns
+<b> Returns</b>
3 The logb functions return the signed exponent of x.
<a name="7.12.6.12" href="#7.12.6.12"><b> 7.12.6.12 The modf functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double modf(double value, double *iptr);
float modff(float value, float *iptr);
long double modfl(long double value, long double *iptr);
- Description
+<b> Description</b>
2 The modf functions break the argument value into integral and fractional parts, each of
which has the same type and sign as the argument. They store the integral part (in
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+
+[<a name="p245" href="#p245">page 245</a>] (<a href="#Contents">Contents</a>)
floating-point format) in the object pointed to by iptr.
- Returns
+<b> Returns</b>
3 The modf functions return the signed fractional part of value.
<a name="7.12.6.13" href="#7.12.6.13"><b> 7.12.6.13 The scalbn and scalbln functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double scalbn(double x, int n);
float scalbnf(float x, int n);
double scalbln(double x, long int n);
float scalblnf(float x, long int n);
long double scalblnl(long double x, long int n);
- Description
+<b> Description</b>
2 The scalbn and scalbln functions compute x x FLT_RADIXn efficiently, not
normally by computing FLT_RADIXn explicitly. A range error may occur.
- Returns
+<b> Returns</b>
3 The scalbn and scalbln functions return x x FLT_RADIXn .
<a name="7.12.7" href="#7.12.7"><b> 7.12.7 Power and absolute-value functions</b></a>
<a name="7.12.7.1" href="#7.12.7.1"><b> 7.12.7.1 The cbrt functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double cbrt(double x);
float cbrtf(float x);
long double cbrtl(long double x);
- Description
+<b> Description</b>
2 The cbrt functions compute the real cube root of x.
- Returns
+<b> Returns</b>
3 The cbrt functions return x1/3 .
-
-
-
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+[<a name="p246" href="#p246">page 246</a>] (<a href="#Contents">Contents</a>)
<a name="7.12.7.2" href="#7.12.7.2"><b> 7.12.7.2 The fabs functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double fabs(double x);
float fabsf(float x);
long double fabsl(long double x);
- Description
+<b> Description</b>
2 The fabs functions compute the absolute value of a floating-point number x.
- Returns
+<b> Returns</b>
3 The fabs functions return | x |.
<a name="7.12.7.3" href="#7.12.7.3"><b> 7.12.7.3 The hypot functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double hypot(double x, double y);
float hypotf(float x, float y);
long double hypotl(long double x, long double y);
- Description
+<b> Description</b>
2 The hypot functions compute the square root of the sum of the squares of x and y,
without undue overflow or underflow. A range error may occur.
3 Returns
-4 The hypot functions return sqrt:x2 + y2 .
+4 The hypot functions return (sqrt)x2 + y2 .
-
-----
<a name="7.12.7.4" href="#7.12.7.4"><b> 7.12.7.4 The pow functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double pow(double x, double y);
float powf(float x, float y);
long double powl(long double x, long double y);
- Description
+<b> Description</b>
2 The pow functions compute x raised to the power y. A domain error occurs if x is finite
and negative and y is finite and not an integer value. A range error may occur. A domain
error may occur if x is zero and y is zero. A domain error or pole error may occur if x is
zero and y is less than zero.
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-
-
-[<a name="#p247" href="p247">page 247</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The pow functions return xy .
<a name="7.12.7.5" href="#7.12.7.5"><b> 7.12.7.5 The sqrt functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double sqrt(double x);
float sqrtf(float x);
long double sqrtl(long double x);
- Description
+<b> Description</b>
2 The sqrt functions compute the nonnegative square root of x. A domain error occurs if
the argument is less than zero.
- Returns
-3 The sqrt functions return sqrt:x.
+<b> Returns</b>
+3 The sqrt functions return (sqrt)x.
-
-
<a name="7.12.8" href="#7.12.8"><b> 7.12.8 Error and gamma functions</b></a>
<a name="7.12.8.1" href="#7.12.8.1"><b> 7.12.8.1 The erf functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double erf(double x);
float erff(float x);
long double erfl(long double x);
- Description
+<b> Description</b>
2 The erf functions compute the error function of x.
- Returns
+<b> Returns</b>
3 2 x
(integral) e-t dt.
2
The erf functions return erf x =
- sqrt:pi
+ (sqrt)pi
-
- 0
<a name="7.12.8.2" href="#7.12.8.2"><b> 7.12.8.2 The erfc functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double erfc(double x);
float erfcf(float x);
long double erfcl(long double x);
- Description
+<b> Description</b>
2 The erfc functions compute the complementary error function of x. A range error
occurs if x is too large.
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- Returns
+[<a name="p248" href="#p248">page 248</a>] (<a href="#Contents">Contents</a>)
+
+<b> Returns</b>
3 2 (inf)
(integral) e-t dt.
2
The erfc functions return erfc x = 1 - erf x =
- sqrt:pi
+ (sqrt)pi
-
- x
<a name="7.12.8.3" href="#7.12.8.3"><b> 7.12.8.3 The lgamma functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double lgamma(double x);
float lgammaf(float x);
long double lgammal(long double x);
- Description
+<b> Description</b>
2 The lgamma functions compute the natural logarithm of the absolute value of gamma of
x. A range error occurs if x is too large. A pole error may occur if x is a negative integer
or zero.
- Returns
+<b> Returns</b>
3 The lgamma functions return loge | (Gamma)(x) |.
<a name="7.12.8.4" href="#7.12.8.4"><b> 7.12.8.4 The tgamma functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double tgamma(double x);
float tgammaf(float x);
long double tgammal(long double x);
- Description
+<b> Description</b>
2 The tgamma functions compute the gamma function of x. A domain error or pole error
may occur if x is a negative integer or zero. A range error occurs if the magnitude of x is
too large and may occur if the magnitude of x is too small.
- Returns
+<b> Returns</b>
3 The tgamma functions return (Gamma)(x).
-
-
-
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<a name="7.12.9" href="#7.12.9"><b> 7.12.9 Nearest integer functions</b></a>
<a name="7.12.9.1" href="#7.12.9.1"><b> 7.12.9.1 The ceil functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double ceil(double x);
float ceilf(float x);
long double ceill(long double x);
- Description
+<b> Description</b>
2 The ceil functions compute the smallest integer value not less than x.
- Returns
+<b> Returns</b>
3 The ceil functions return [^x^], expressed as a floating-point number.
<a name="7.12.9.2" href="#7.12.9.2"><b> 7.12.9.2 The floor functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double floor(double x);
float floorf(float x);
long double floorl(long double x);
- Description
+<b> Description</b>
2 The floor functions compute the largest integer value not greater than x.
- Returns
+<b> Returns</b>
3 The floor functions return [_x_], expressed as a floating-point number.
<a name="7.12.9.3" href="#7.12.9.3"><b> 7.12.9.3 The nearbyint functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double nearbyint(double x);
float nearbyintf(float x);
long double nearbyintl(long double x);
- Description
+<b> Description</b>
2 The nearbyint functions round their argument to an integer value in floating-point
format, using the current rounding direction and without raising the ''inexact'' floating-
point exception.
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-
-
-[<a name="#p250" href="p250">page 250</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The nearbyint functions return the rounded integer value.
<a name="7.12.9.4" href="#7.12.9.4"><b> 7.12.9.4 The rint functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double rint(double x);
float rintf(float x);
long double rintl(long double x);
- Description
+<b> Description</b>
2 The rint functions differ from the nearbyint functions (<a href="#7.12.9.3">7.12.9.3</a>) only in that the
rint functions may raise the ''inexact'' floating-point exception if the result differs in
value from the argument.
- Returns
+<b> Returns</b>
3 The rint functions return the rounded integer value.
<a name="7.12.9.5" href="#7.12.9.5"><b> 7.12.9.5 The lrint and llrint functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
long int lrint(double x);
long int lrintf(float x);
long long int llrint(double x);
long long int llrintf(float x);
long long int llrintl(long double x);
- Description
+<b> Description</b>
2 The lrint and llrint functions round their argument to the nearest integer value,
rounding according to the current rounding direction. If the rounded value is outside the
range of the return type, the numeric result is unspecified and a domain error or range
error may occur.
- Returns
+<b> Returns</b>
3 The lrint and llrint functions return the rounded integer value.
-
-
-
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<a name="7.12.9.6" href="#7.12.9.6"><b> 7.12.9.6 The round functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double round(double x);
float roundf(float x);
long double roundl(long double x);
- Description
+<b> Description</b>
2 The round functions round their argument to the nearest integer value in floating-point
format, rounding halfway cases away from zero, regardless of the current rounding
direction.
- Returns
+<b> Returns</b>
3 The round functions return the rounded integer value.
<a name="7.12.9.7" href="#7.12.9.7"><b> 7.12.9.7 The lround and llround functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
long int lround(double x);
long int lroundf(float x);
long long int llround(double x);
long long int llroundf(float x);
long long int llroundl(long double x);
- Description
+<b> Description</b>
2 The lround and llround functions round their argument to the nearest integer value,
rounding halfway cases away from zero, regardless of the current rounding direction. If
the rounded value is outside the range of the return type, the numeric result is unspecified
and a domain error or range error may occur.
- Returns
+<b> Returns</b>
3 The lround and llround functions return the rounded integer value.
<a name="7.12.9.8" href="#7.12.9.8"><b> 7.12.9.8 The trunc functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double trunc(double x);
float truncf(float x);
long double truncl(long double x);
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-[<a name="#p252" href="p252">page 252</a>] (<a href="#Contents">Contents</a>)
-
- Description
+<b> Description</b>
2 The trunc functions round their argument to the integer value, in floating format,
nearest to but no larger in magnitude than the argument.
- Returns
+<b> Returns</b>
3 The trunc functions return the truncated integer value.
<a name="7.12.10" href="#7.12.10"><b> 7.12.10 Remainder functions</b></a>
<a name="7.12.10.1" href="#7.12.10.1"><b> 7.12.10.1 The fmod functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double fmod(double x, double y);
float fmodf(float x, float y);
long double fmodl(long double x, long double y);
- Description
+<b> Description</b>
2 The fmod functions compute the floating-point remainder of x/y.
- Returns
+<b> Returns</b>
3 The fmod functions return the value x - ny, for some integer n such that, if y is nonzero,
the result has the same sign as x and magnitude less than the magnitude of y. If y is zero,
whether a domain error occurs or the fmod functions return zero is implementation-
defined.
<a name="7.12.10.2" href="#7.12.10.2"><b> 7.12.10.2 The remainder functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double remainder(double x, double y);
float remainderf(float x, float y);
long double remainderl(long double x, long double y);
- Description
-2 The remainder functions compute the remainder x REM y required by IEC 60559.236)
+<b> Description</b>
+2 The remainder functions compute the remainder x REM y required by IEC 60559.<sup><a href="#note236"><b>236)</b></a></sup>
- 236) ''When y != 0, the remainder r = x REM y is defined regardless of the rounding mode by the
+ <sup><a name="note236" href="#note236"><b>236)</b></a></sup> ''When y != 0, the remainder r = x REM y is defined regardless of the rounding mode by the
mathematical relation r = x - ny, where n is the integer nearest the exact value of x/y; whenever
| n - x/y | = 1/2, then n is even. If r = 0, its sign shall be that of x.'' This definition is applicable for *
all implementations.
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#p253" href="p253">page 253</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p253" href="#p253">page 253</a>] (<a href="#Contents">Contents</a>)
- Returns
+<b> Returns</b>
3 The remainder functions return x REM y. If y is zero, whether a domain error occurs
or the functions return zero is implementation defined.
<a name="7.12.10.3" href="#7.12.10.3"><b> 7.12.10.3 The remquo functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double remquo(double x, double y, int *quo);
float remquof(float x, float y, int *quo);
long double remquol(long double x, long double y,
int *quo);
- Description
+<b> Description</b>
2 The remquo functions compute the same remainder as the remainder functions. In
the object pointed to by quo they store a value whose sign is the sign of x/y and whose
magnitude is congruent modulo 2n to the magnitude of the integral quotient of x/y, where
n is an implementation-defined integer greater than or equal to 3.
- Returns
+<b> Returns</b>
3 The remquo functions return x REM y. If y is zero, the value stored in the object
pointed to by quo is unspecified and whether a domain error occurs or the functions
return zero is implementation defined.
<a name="7.12.11" href="#7.12.11"><b> 7.12.11 Manipulation functions</b></a>
<a name="7.12.11.1" href="#7.12.11.1"><b> 7.12.11.1 The copysign functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double copysign(double x, double y);
float copysignf(float x, float y);
long double copysignl(long double x, long double y);
- Description
+<b> Description</b>
2 The copysign functions produce a value with the magnitude of x and the sign of y.
They produce a NaN (with the sign of y) if x is a NaN. On implementations that
represent a signed zero but do not treat negative zero consistently in arithmetic
operations, the copysign functions regard the sign of zero as positive.
- Returns
+<b> Returns</b>
3 The copysign functions return a value with the magnitude of x and the sign of y.
-
-
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<a name="7.12.11.2" href="#7.12.11.2"><b> 7.12.11.2 The nan functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double nan(const char *tagp);
float nanf(const char *tagp);
long double nanl(const char *tagp);
- Description
+<b> Description</b>
2 The call nan("n-char-sequence") is equivalent to strtod("NAN(n-char-
sequence)", (char**) NULL); the call nan("") is equivalent to
strtod("NAN()", (char**) NULL). If tagp does not point to an n-char
sequence or an empty string, the call is equivalent to strtod("NAN", (char**)
NULL). Calls to nanf and nanl are equivalent to the corresponding calls to strtof
and strtold.
- Returns
+<b> Returns</b>
3 The nan functions return a quiet NaN, if available, with content indicated through tagp.
If the implementation does not support quiet NaNs, the functions return zero.
Forward references: the strtod, strtof, and strtold functions (<a href="#7.22.1.3">7.22.1.3</a>).
<a name="7.12.11.3" href="#7.12.11.3"><b> 7.12.11.3 The nextafter functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double nextafter(double x, double y);
float nextafterf(float x, float y);
long double nextafterl(long double x, long double y);
- Description
+<b> Description</b>
2 The nextafter functions determine the next representable value, in the type of the
function, after x in the direction of y, where x and y are first converted to the type of the
- function.237) The nextafter functions return y if x equals y. A range error may occur
+ function.<sup><a href="#note237"><b>237)</b></a></sup> The nextafter functions return y if x equals y. A range error may occur
if the magnitude of x is the largest finite value representable in the type and the result is
infinite or not representable in the type.
- Returns
+<b> Returns</b>
3 The nextafter functions return the next representable value in the specified format
after x in the direction of y.
- 237) The argument values are converted to the type of the function, even by a macro implementation of the
+ <sup><a name="note237" href="#note237"><b>237)</b></a></sup> The argument values are converted to the type of the function, even by a macro implementation of the
function.
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+[<a name="
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<a name="7.12.11.4" href="#7.12.11.4"><b> 7.12.11.4 The nexttoward functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double nexttoward(double x, long double y);
float nexttowardf(float x, long double y);
long double nexttowardl(long double x, long double y);
- Description
+<b> Description</b>
2 The nexttoward functions are equivalent to the nextafter functions except that the
second parameter has type long double and the functions return y converted to the
- type of the function if x equals y.238)
+ type of the function if x equals y.<sup><a href="#note238"><b>238)</b></a></sup>
<a name="7.12.12" href="#7.12.12"><b> 7.12.12 Maximum, minimum, and positive difference functions</b></a>
<a name="7.12.12.1" href="#7.12.12.1"><b> 7.12.12.1 The fdim functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double fdim(double x, double y);
float fdimf(float x, float y);
long double fdiml(long double x, long double y);
- Description
+<b> Description</b>
2 The fdim functions determine the positive difference between their arguments:
{x - y if x > y
{
{+0 if x <= y
A range error may occur.
- Returns
+<b> Returns</b>
3 The fdim functions return the positive difference value.
<a name="7.12.12.2" href="#7.12.12.2"><b> 7.12.12.2 The fmax functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double fmax(double x, double y);
float fmaxf(float x, float y);
- 238) The result of the nexttoward functions is determined in the type of the function, without loss of
+ <sup><a name="note238" href="#note238"><b>238)</b></a></sup> The result of the nexttoward functions is determined in the type of the function, without loss of
range or precision in a floating second argument.
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+[<a name="
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- Description
-2 The fmax functions determine the maximum numeric value of their arguments.239)
- Returns
+<b> Description</b>
+2 The fmax functions determine the maximum numeric value of their arguments.<sup><a href="#note239"><b>239)</b></a></sup>
+<b> Returns</b>
3 The fmax functions return the maximum numeric value of their arguments.
<a name="7.12.12.3" href="#7.12.12.3"><b> 7.12.12.3 The fmin functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double fmin(double x, double y);
float fminf(float x, float y);
long double fminl(long double x, long double y);
- Description
-2 The fmin functions determine the minimum numeric value of their arguments.240)
- Returns
+<b> Description</b>
+2 The fmin functions determine the minimum numeric value of their arguments.<sup><a href="#note240"><b>240)</b></a></sup>
+<b> Returns</b>
3 The fmin functions return the minimum numeric value of their arguments.
<a name="7.12.13" href="#7.12.13"><b> 7.12.13 Floating multiply-add</b></a>
<a name="7.12.13.1" href="#7.12.13.1"><b> 7.12.13.1 The fma functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
double fma(double x, double y, double z);
float fmaf(float x, float y, float z);
long double fmal(long double x, long double y,
long double z);
- Description
+<b> Description</b>
2 The fma functions compute (x x y) + z, rounded as one ternary operation: they compute
the value (as if) to infinite precision and round once to the result format, according to the
current rounding mode. A range error may occur.
- Returns
+<b> Returns</b>
3 The fma functions return (x x y) + z, rounded as one ternary operation.
- 239) NaN arguments are treated as missing data: if one argument is a NaN and the other numeric, then the
+ <sup><a name="note239" href="#note239"><b>239)</b></a></sup> NaN arguments are treated as missing data: if one argument is a NaN and the other numeric, then the
fmax functions choose the numeric value. See <a href="#F.10.9.2">F.10.9.2</a>.
- 240) The fmin functions are analogous to the fmax functions in their treatment of NaNs.
+ <sup><a name="note240" href="#note240"><b>240)</b></a></sup> The fmin functions are analogous to the fmax functions in their treatment of NaNs.
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<a name="7.12.14" href="#7.12.14"><b> 7.12.14 Comparison macros</b></a>
1 The relational and equality operators support the usual mathematical relationships
between numeric values. For any ordered pair of numeric values exactly one of the
relationships -- less, greater, and equal -- is true. Relational operators may raise the
''invalid'' floating-point exception when argument values are NaNs. For a NaN and a
- numeric value, or for two NaNs, just the unordered relationship is true.241) The following
+ numeric value, or for two NaNs, just the unordered relationship is true.<sup><a href="#note241"><b>241)</b></a></sup> The following
subclauses provide macros that are quiet (non floating-point exception raising) versions
of the relational operators, and other comparison macros that facilitate writing efficient
code that accounts for NaNs without suffering the ''invalid'' floating-point exception. In
the synopses in this subclause, real-floating indicates that the argument shall be an
- expression of real floating type242) (both arguments need not have the same type).243)
+ expression of real floating type<sup><a href="#note242"><b>242)</b></a></sup> (both arguments need not have the same type).<sup><a href="#note243"><b>243)</b></a></sup>
<a name="7.12.14.1" href="#7.12.14.1"><b> 7.12.14.1 The isgreater macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int isgreater(real-floating x, real-floating y);
- Description
+<b> Description</b>
2 The isgreater macro determines whether its first argument is greater than its second
argument. The value of isgreater(x, y) is always equal to (x) > (y); however,
unlike (x) > (y), isgreater(x, y) does not raise the ''invalid'' floating-point
exception when x and y are unordered.
- Returns
+<b> Returns</b>
3 The isgreater macro returns the value of (x) > (y).
<a name="7.12.14.2" href="#7.12.14.2"><b> 7.12.14.2 The isgreaterequal macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int isgreaterequal(real-floating x, real-floating y);
- 241) IEC 60559 requires that the built-in relational operators raise the ''invalid'' floating-point exception if
+ <sup><a name="note241" href="#note241"><b>241)</b></a></sup> IEC 60559 requires that the built-in relational operators raise the ''invalid'' floating-point exception if
the operands compare unordered, as an error indicator for programs written without consideration of
NaNs; the result in these cases is false.
- 242) If any argument is of integer type, or any other type that is not a real floating type, the behavior is
+ <sup><a name="note242" href="#note242"><b>242)</b></a></sup> If any argument is of integer type, or any other type that is not a real floating type, the behavior is
undefined.
- 243) Whether an argument represented in a format wider than its semantic type is converted to the semantic
+ <sup><a name="note243" href="#note243"><b>243)</b></a></sup> Whether an argument represented in a format wider than its semantic type is converted to the semantic
type is unspecified.
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+[<a name="
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- Description
+<b> Description</b>
2 The isgreaterequal macro determines whether its first argument is greater than or
equal to its second argument. The value of isgreaterequal(x, y) is always equal
to (x) >= (y); however, unlike (x) >= (y), isgreaterequal(x, y) does
not raise the ''invalid'' floating-point exception when x and y are unordered.
- Returns
+<b> Returns</b>
3 The isgreaterequal macro returns the value of (x) >= (y).
<a name="7.12.14.3" href="#7.12.14.3"><b> 7.12.14.3 The isless macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int isless(real-floating x, real-floating y);
- Description
+<b> Description</b>
2 The isless macro determines whether its first argument is less than its second
argument. The value of isless(x, y) is always equal to (x) < (y); however,
unlike (x) < (y), isless(x, y) does not raise the ''invalid'' floating-point
exception when x and y are unordered.
- Returns
+<b> Returns</b>
3 The isless macro returns the value of (x) < (y).
<a name="7.12.14.4" href="#7.12.14.4"><b> 7.12.14.4 The islessequal macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int islessequal(real-floating x, real-floating y);
- Description
+<b> Description</b>
2 The islessequal macro determines whether its first argument is less than or equal to
its second argument. The value of islessequal(x, y) is always equal to
(x) <= (y); however, unlike (x) <= (y), islessequal(x, y) does not raise
the ''invalid'' floating-point exception when x and y are unordered.
- Returns
+<b> Returns</b>
3 The islessequal macro returns the value of (x) <= (y).
-
-
-
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<a name="7.12.14.5" href="#7.12.14.5"><b> 7.12.14.5 The islessgreater macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int islessgreater(real-floating x, real-floating y);
- Description
+<b> Description</b>
2 The islessgreater macro determines whether its first argument is less than or
greater than its second argument. The islessgreater(x, y) macro is similar to
(x) < (y) || (x) > (y); however, islessgreater(x, y) does not raise
the ''invalid'' floating-point exception when x and y are unordered (nor does it evaluate x
and y twice).
- Returns
+<b> Returns</b>
3 The islessgreater macro returns the value of (x) < (y) || (x) > (y).
<a name="7.12.14.6" href="#7.12.14.6"><b> 7.12.14.6 The isunordered macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.12"><math.h></a>
int isunordered(real-floating x, real-floating y);
- Description
+<b> Description</b>
2 The isunordered macro determines whether its arguments are unordered.
- Returns
+<b> Returns</b>
3 The isunordered macro returns 1 if its arguments are unordered and 0 otherwise.
-
-
-
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+[<a name="p260" href="#p260">page 260</a>] (<a href="#Contents">Contents</a>)
<a name="7.13" href="#7.13"><b> 7.13 Nonlocal jumps <setjmp.h></b></a>
1 The header <a href="#7.13"><setjmp.h></a> defines the macro setjmp, and declares one function and
- one type, for bypassing the normal function call and return discipline.244)
+ one type, for bypassing the normal function call and return discipline.<sup><a href="#note244"><b>244)</b></a></sup>
2 The type declared is
jmp_buf
which is an array type suitable for holding the information needed to restore a calling
program defines an external identifier with the name setjmp, the behavior is undefined.
<a name="7.13.1" href="#7.13.1"><b> 7.13.1 Save calling environment</b></a>
<a name="7.13.1.1" href="#7.13.1.1"><b> 7.13.1.1 The setjmp macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.13"><setjmp.h></a>
int setjmp(jmp_buf env);
- Description
+<b> Description</b>
2 The setjmp macro saves its calling environment in its jmp_buf argument for later use
by the longjmp function.
- Returns
+<b> Returns</b>
3 If the return is from a direct invocation, the setjmp macro returns the value zero. If the
return is from a call to the longjmp function, the setjmp macro returns a nonzero
value.
constant expression, with the resulting expression being the entire controlling
- 244) These functions are useful for dealing with unusual conditions encountered in a low-level function of
+ <sup><a name="note244" href="#note244"><b>244)</b></a></sup> These functions are useful for dealing with unusual conditions encountered in a low-level function of
a program.
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expression of a selection or iteration statement;
-- the operand of a unary ! operator with the resulting expression being the entire
5 If the invocation appears in any other context, the behavior is undefined.
<a name="7.13.2" href="#7.13.2"><b> 7.13.2 Restore calling environment</b></a>
<a name="7.13.2.1" href="#7.13.2.1"><b> 7.13.2.1 The longjmp function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.13"><setjmp.h></a>
_Noreturn void longjmp(jmp_buf env, int val);
- Description
+<b> Description</b>
2 The longjmp function restores the environment saved by the most recent invocation of
the setjmp macro in the same invocation of the program with the corresponding
jmp_buf argument. If there has been no such invocation, or if the function containing
- the invocation of the setjmp macro has terminated execution245) in the interim, or if the
+ the invocation of the setjmp macro has terminated execution<sup><a href="#note245"><b>245)</b></a></sup> in the interim, or if the
invocation of the setjmp macro was within the scope of an identifier with variably
modified type and execution has left that scope in the interim, the behavior is undefined.
-3 All accessible objects have values, and all other components of the abstract machine246)
+3 All accessible objects have values, and all other components of the abstract machine<sup><a href="#note246"><b>246)</b></a></sup>
have state, as of the time the longjmp function was called, except that the values of
objects of automatic storage duration that are local to the function containing the
invocation of the corresponding setjmp macro that do not have volatile-qualified type
and have been changed between the setjmp invocation and longjmp call are
indeterminate.
- Returns
+<b> Returns</b>
4 After longjmp is completed, program execution continues as if the corresponding
invocation of the setjmp macro had just returned the value specified by val. The
longjmp function cannot cause the setjmp macro to return the value 0; if val is 0,
- 245) For example, by executing a return statement or because another longjmp call has caused a
+ <sup><a name="note245" href="#note245"><b>245)</b></a></sup> For example, by executing a return statement or because another longjmp call has caused a
transfer to a setjmp invocation in a function earlier in the set of nested calls.
- 246) This includes, but is not limited to, the floating-point status flags and the state of open files.
+ <sup><a name="note246" href="#note246"><b>246)</b></a></sup> This includes, but is not limited to, the floating-point status flags and the state of open files.
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#include <a href="#7.13"><setjmp.h></a>
jmp_buf buf;
longjmp(buf, 2); // might cause memory loss
}
-
-
-
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+[<a name="p263" href="#p263">page 263</a>] (<a href="#Contents">Contents</a>)
<a name="7.14" href="#7.14"><b> 7.14 Signal handling <signal.h></b></a>
1 The header <a href="#7.14"><signal.h></a> declares a type and two functions and defines several macros,
4 An implementation need not generate any of these signals, except as a result of explicit
calls to the raise function. Additional signals and pointers to undeclarable functions,
with macro definitions beginning, respectively, with the letters SIG and an uppercase
- letter or with SIG_ and an uppercase letter,247) may also be specified by the
+ letter or with SIG_ and an uppercase letter,<sup><a href="#note247"><b>247)</b></a></sup> may also be specified by the
implementation. The complete set of signals, their semantics, and their default handling
is implementation-defined; all signal numbers shall be positive.
-
247) See ''future library directions'' (<a href="#7.30.6">7.30.6</a>). The names of the signal numbers reflect the following terms
+
<sup><a name="note247" href="#note247"><b>247)</b></a></sup> See ''future library directions'' (<a href="#7.30.6">7.30.6</a>). The names of the signal numbers reflect the following terms
(respectively): abort, floating-point exception, illegal instruction, interrupt, segmentation violation,
and termination.
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<a name="7.14.1" href="#7.14.1"><b> 7.14.1 Specify signal handling</b></a>
<a name="7.14.1.1" href="#7.14.1.1"><b> 7.14.1.1 The signal function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.14"><signal.h></a>
void (*signal(int sig, void (*func)(int)))(int);
- Description
+<b> Description</b>
2 The signal function chooses one of three ways in which receipt of the signal number
sig is to be subsequently handled. If the value of func is SIG_DFL, default handling
for that signal will occur. If the value of func is SIG_IGN, the signal will be ignored.
Otherwise, func shall point to a function to be called when that signal occurs. An
invocation of such a function because of a signal, or (recursively) of any further functions
- called by that invocation (other than functions in the standard library),248) is called a
+ called by that invocation (other than functions in the standard library),<sup><a href="#note248"><b>248)</b></a></sup> is called a
signal handler.
3 When a signal occurs and func points to a function, it is implementation-defined
whether the equivalent of signal(sig, SIG_DFL); is executed or the
quick_exit function, or the signal function with the first argument equal to the
signal number corresponding to the signal that caused the invocation of the handler.
Furthermore, if such a call to the signal function results in a SIG_ERR return, the
- value of errno is indeterminate.249)
+ value of errno is indeterminate.<sup><a href="#note249"><b>249)</b></a></sup>
- 248) This includes functions called indirectly via standard library functions (e.g., a SIGABRT handler
+ <sup><a name="note248" href="#note248"><b>248)</b></a></sup> This includes functions called indirectly via standard library functions (e.g., a SIGABRT handler
called via the abort function).
- 249) If any signal is generated by an asynchronous signal handler, the behavior is undefined.
+ <sup><a name="note249" href="#note249"><b>249)</b></a></sup> If any signal is generated by an asynchronous signal handler, the behavior is undefined.
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6 At program startup, the equivalent of
signal(sig, SIG_IGN);
signal(sig, SIG_DFL);
is executed for all other signals defined by the implementation.
7 The implementation shall behave as if no library function calls the signal function.
- Returns
+<b> Returns</b>
8 If the request can be honored, the signal function returns the value of func for the
most recent successful call to signal for the specified signal sig. Otherwise, a value of
SIG_ERR is returned and a positive value is stored in errno.
_Exit function (<a href="#7.22.4.5">7.22.4.5</a>), the quick_exit function (<a href="#7.22.4.7">7.22.4.7</a>).
<a name="7.14.2" href="#7.14.2"><b> 7.14.2 Send signal</b></a>
<a name="7.14.2.1" href="#7.14.2.1"><b> 7.14.2.1 The raise function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.14"><signal.h></a>
int raise(int sig);
- Description
+<b> Description</b>
2 The raise function carries out the actions described in <a href="#7.14.1.1">7.14.1.1</a> for the signal sig. If a
signal handler is called, the raise function shall not return until after the signal handler
does.
- Returns
+<b> Returns</b>
3 The raise function returns zero if successful, nonzero if unsuccessful.
-
-
-
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+[<a name="p266" href="#p266">page 266</a>] (<a href="#Contents">Contents</a>)
<a name="7.15" href="#7.15"><b> 7.15 Alignment <stdalign.h></b></a>
1 The header <a href="#7.15"><stdalign.h></a> defines two macros.
__alignas_is_defined
which expands to the integer constant 1.
-
-
-
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+[<a name="p267" href="#p267">page 267</a>] (<a href="#Contents">Contents</a>)
<a name="7.16" href="#7.16"><b> 7.16 Variable arguments <stdarg.h></b></a>
1 The header <a href="#7.16"><stdarg.h></a> declares a type and defines four macros, for advancing
subclause) having type va_list. The object ap may be passed as an argument to
another function; if that function invokes the va_arg macro with parameter ap, the
value of ap in the calling function is indeterminate and shall be passed to the va_end
- macro prior to any further reference to ap.250)
+ macro prior to any further reference to ap.<sup><a href="#note250"><b>250)</b></a></sup>
<a name="7.16.1" href="#7.16.1"><b> 7.16.1 Variable argument list access macros</b></a>
1 The va_start and va_arg macros described in this subclause shall be implemented
as macros, not functions. It is unspecified whether va_copy and va_end are macros or
shall be matched by a corresponding invocation of the va_end macro in the same
function.
<a name="7.16.1.1" href="#7.16.1.1"><b> 7.16.1.1 The va_arg macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
type va_arg(va_list ap, type);
- Description
+<b> Description</b>
2 The va_arg macro expands to an expression that has the specified type and the value of
the next argument in the call. The parameter ap shall have been initialized by the
va_start or va_copy macro (without an intervening invocation of the va_end
- 250) It is permitted to create a pointer to a va_list and pass that pointer to another function, in which
+ <sup><a name="note250" href="#note250"><b>250)</b></a></sup> It is permitted to create a pointer to a va_list and pass that pointer to another function, in which
case the original function may make further use of the original list after the other function returns.
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macro for the same ap). Each invocation of the va_arg macro modifies ap so that the
values of successive arguments are returned in turn. The parameter type shall be a type
-- one type is a signed integer type, the other type is the corresponding unsigned integer
type, and the value is representable in both types;
-- one type is pointer to void and the other is a pointer to a character type.
- Returns
+<b> Returns</b>
3 The first invocation of the va_arg macro after that of the va_start macro returns the
value of the argument after that specified by parmN . Successive invocations return the
values of the remaining arguments in succession.
<a name="7.16.1.2" href="#7.16.1.2"><b> 7.16.1.2 The va_copy macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
void va_copy(va_list dest, va_list src);
- Description
+<b> Description</b>
2 The va_copy macro initializes dest as a copy of src, as if the va_start macro had
been applied to dest followed by the same sequence of uses of the va_arg macro as
had previously been used to reach the present state of src. Neither the va_copy nor
va_start macro shall be invoked to reinitialize dest without an intervening
invocation of the va_end macro for the same dest.
- Returns
+<b> Returns</b>
3 The va_copy macro returns no value.
<a name="7.16.1.3" href="#7.16.1.3"><b> 7.16.1.3 The va_end macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
void va_end(va_list ap);
- Description
+<b> Description</b>
2 The va_end macro facilitates a normal return from the function whose variable
argument list was referred to by the expansion of the va_start macro, or the function
containing the expansion of the va_copy macro, that initialized the va_list ap. The
va_end macro may modify ap so that it is no longer usable (without being reinitialized
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by the va_start or va_copy macro). If there is no corresponding invocation of the
va_start or va_copy macro, or if the va_end macro is not invoked before the
return, the behavior is undefined.
- Returns
+<b> Returns</b>
3 The va_end macro returns no value.
<a name="7.16.1.4" href="#7.16.1.4"><b> 7.16.1.4 The va_start macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
void va_start(va_list ap, parmN);
- Description
+<b> Description</b>
2 The va_start macro shall be invoked before any access to the unnamed arguments.
3 The va_start macro initializes ap for subsequent use by the va_arg and va_end
macros. Neither the va_start nor va_copy macro shall be invoked to reinitialize ap
parmN is declared with the register storage class, with a function or array type, or
with a type that is not compatible with the type that results after application of the default
argument promotions, the behavior is undefined.
- Returns
+<b> Returns</b>
5 The va_start macro returns no value.
6 EXAMPLE 1 The function f1 gathers into an array a list of arguments that are pointers to strings (but not
more than MAXARGS arguments), then passes the array as a single argument to function f2. The number of
char *array[MAXARGS];
int ptr_no = 0;
-
-
-
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if (n_ptrs > MAXARGS)
n_ptrs = MAXARGS;
f4(n_ptrs, array);
}
-
-
-
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+[<a name="p271" href="#p271">page 271</a>] (<a href="#Contents">Contents</a>)
<a name="7.17" href="#7.17"><b> 7.17 Atomics <stdatomic.h></b></a>
<a name="7.17.1" href="#7.17.1"><b> 7.17.1 Introduction</b></a>
5 In the following operation definitions:
-- An A refers to one of the atomic types.
-
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-- A C refers to its corresponding non-atomic type. The atomic_address atomic
type corresponds to the void * non-atomic type.
<a name="7.17.2" href="#7.17.2"><b> 7.17.2 Initialization</b></a>
<a name="7.17.2.1" href="#7.17.2.1"><b> 7.17.2.1 The ATOMIC_VAR_INIT macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.17"><stdatomic.h></a>
#define ATOMIC_VAR_INIT(C value)
- Description
+<b> Description</b>
2 The ATOMIC_VAR_INIT macro expands to a token sequence suitable for initializing an
atomic object of a type that is initialization-compatible with value. An atomic object
with automatic storage duration that is not explicitly initialized using
atomic_int guide = ATOMIC_VAR_INIT(42);
<a name="7.17.2.2" href="#7.17.2.2"><b> 7.17.2.2 The atomic_init generic function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.17"><stdatomic.h></a>
void atomic_init(volatile A *obj, C value);
- Description
+<b> Description</b>
2 The atomic_init generic function initializes the atomic object pointed to by obj to
the value value, while also initializing any additional state that the implementation
might need to carry for the atomic object.
-
-
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3 Although this function initializes an atomic object, it does not avoid data races;
concurrent access to the variable being initialized, even via an atomic operation,
constitutes a data race.
- Returns
+<b> Returns</b>
4 The atomic_init generic function returns no value.
5 EXAMPLE
atomic_int guide;
8 NOTE 2 Atomic operations specifying memory_order_relaxed are relaxed only with respect to
memory ordering. Implementations must still guarantee that any given atomic access to a particular atomic
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object be indivisible with respect to all other atomic accesses to that object.
13 An atomic store shall only store a value that has been computed from constants and
program input values by a finite sequence of program evaluations, such that each
evaluation observes the values of variables as computed by the last prior assignment in
- the sequence.251) The ordering of evaluations in this sequence shall be such that
+ the sequence.<sup><a href="#note251"><b>251)</b></a></sup> The ordering of evaluations in this sequence shall be such that
-- If an evaluation B observes a value computed by A in a different thread, then B does
not happen before A.
-- If an evaluation A is included in the sequence, then all evaluations that assign to the
- 251) Among other implications, atomic variables shall not decay.
+ <sup><a name="note251" href="#note251"><b>251)</b></a></sup> Among other implications, atomic variables shall not decay.
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atomic_store_explicit(&y, 42, memory_order_relaxed);
r1 = atomic_load_explicit(&y, memory_order_relaxed);
16 Implementations should make atomic stores visible to atomic loads within a reasonable
amount of time.
<a name="7.17.3.1" href="#7.17.3.1"><b> 7.17.3.1 The kill_dependency macro</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.17"><stdatomic.h></a>
type kill_dependency(type y);
- Description
+<b> Description</b>
2 The kill_dependency macro terminates a dependency chain; the argument does not
carry a dependency to the return value.
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-
-[<a name="#p276" href="p276">page 276</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The kill_dependency macro returns the value of y.
<a name="7.17.4" href="#7.17.4"><b> 7.17.4 Fences</b></a>
1 This subclause introduces synchronization primitives called fences. Fences can have
sequenced before B and reads the value written by A or a value written by any side effect
in the release sequence headed by A.
<a name="7.17.4.1" href="#7.17.4.1"><b> 7.17.4.1 The atomic_thread_fence function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.17"><stdatomic.h></a>
void atomic_thread_fence(memory_order order);
- Description
+<b> Description</b>
2 Depending on the value of order, this operation:
-- has no effects, if order == memory_order_relaxed;
-- is an acquire fence, if order == memory_order_acquire or order ==
-- is a sequentially consistent acquire and release fence, if order ==
memory_order_seq_cst.
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-[<a name="#p277" href="p277">page 277</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The atomic_thread_fence function returns no value.
<a name="7.17.4.2" href="#7.17.4.2"><b> 7.17.4.2 The atomic_signal_fence function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.17"><stdatomic.h></a>
void atomic_signal_fence(memory_order order);
- Description
+<b> Description</b>
2 Equivalent to atomic_thread_fence(order), except that ''synchronizes with''
relationships are established only between a thread and a signal handler executed in the
same thread.
atomic_thread_fence, but the hardware fence instructions that atomic_thread_fence would
have inserted are not emitted.
- Returns
+<b> Returns</b>
5 The atomic_signal_fence function returns no value.
<a name="7.17.5" href="#7.17.5"><b> 7.17.5 Lock-free property</b></a>
1 The atomic lock-free macros indicate the lock-free property of integer and address atomic
process more than once and memory shared between two processes.
<a name="7.17.5.1" href="#7.17.5.1"><b> 7.17.5.1 The atomic_is_lock_free generic function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.17"><stdatomic.h></a>
_Bool atomic_is_lock_free(atomic_type const volatile *obj);
- Description
+<b> Description</b>
2 The atomic_is_lock_free generic function indicates whether or not the object
pointed to by obj is lock-free. atomic_type can be any atomic type.
- Returns
+<b> Returns</b>
3 The atomic_is_lock_free generic function returns nonzero (true) if and only if the
object's operations are lock-free. The result of a lock-free query on one object cannot be
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inferred from the result of a lock-free query on another object.
<a name="7.17.6" href="#7.17.6"><b> 7.17.6 Atomic integer and address types</b></a>
1 For each line in the following table, the atomic type name is declared as the
corresponding direct type.
-
-
-
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+[<a name="p279" href="#p279">page 279</a>] (<a href="#Contents">Contents</a>)
Atomic type name Direct type
atomic_char _Atomic char
2 The semantics of the operations on these types are defined in <a href="#7.17.7">7.17.7</a>.
3 The atomic_bool type provides an atomic boolean.
-
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+[<a name="p280" href="#p280">page 280</a>] (<a href="#Contents">Contents</a>)
4 The atomic_address type provides atomic void * operations. The unit of
addition/subtraction shall be one byte.
1 There are only a few kinds of operations on atomic types, though there are many
instances of those kinds. This subclause specifies each general kind.
<a name="7.17.7.1" href="#7.17.7.1"><b> 7.17.7.1 The atomic_store generic functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.17"><stdatomic.h></a>
void atomic_store(volatile A *object, C desired);
void atomic_store_explicit(volatile A *object,
C desired, memory_order order);
- Description
+<b> Description</b>
2 The order argument shall not be memory_order_acquire,
memory_order_consume, nor memory_order_acq_rel. Atomically replace the
value pointed to by object with the value of desired. Memory is affected according
to the value of order.
- Returns
+<b> Returns</b>
3 The atomic_store generic functions return no value.
<a name="7.17.7.2" href="#7.17.7.2"><b> 7.17.7.2 The atomic_load generic functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.17"><stdatomic.h></a>
C atomic_load(volatile A *object);
C atomic_load_explicit(volatile A *object,
memory_order order);
- Description
+<b> Description</b>
2 The order argument shall not be memory_order_release nor
memory_order_acq_rel. Memory is affected according to the value of order.
- Returns
+<b> Returns</b>
Atomically returns the value pointed to by object.
-
-
-
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+[<a name="p281" href="#p281">page 281</a>] (<a href="#Contents">Contents</a>)
<a name="7.17.7.3" href="#7.17.7.3"><b> 7.17.7.3 The atomic_exchange generic functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.17"><stdatomic.h></a>
C atomic_exchange(volatile A *object, C desired);
C atomic_exchange_explicit(volatile A *object,
C desired, memory_order order);
- Description
+<b> Description</b>
2 Atomically replace the value pointed to by object with desired. Memory is affected
according to the value of order. These operations are read-modify-write operations
(<a href="#5.1.2.4">5.1.2.4</a>).
- Returns
+<b> Returns</b>
3 Atomically returns the value pointed to by object immediately before the effects.
<a name="7.17.7.4" href="#7.17.7.4"><b> 7.17.7.4 The atomic_compare_exchange generic functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.17"><stdatomic.h></a>
_Bool atomic_compare_exchange_strong(volatile A *object,
C *expected, C desired);
_Bool atomic_compare_exchange_weak_explicit(
volatile A *object, C *expected, C desired,
memory_order success, memory_order failure);
- Description
+<b> Description</b>
2 The failure argument shall not be memory_order_release nor
memory_order_acq_rel. The failure argument shall be no stronger than the
success argument. Atomically, compares the value pointed to by object for equality
failure. These operations are atomic read-modify-write operations (<a href="#5.1.2.4">5.1.2.4</a>).
3 NOTE 1 The effect of the compare-and-exchange operations is
-
-
-
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if (*object == *expected)
*object = desired;
platforms. When a weak compare-and-exchange would require a loop and a strong one would not, the
strong one is preferable.
- Returns
+<b> Returns</b>
7 The result of the comparison.
<a name="7.17.7.5" href="#7.17.7.5"><b> 7.17.7.5 The atomic_fetch and modify generic functions</b></a>
1 The following operations perform arithmetic and bitwise computations. All of these
or | bitwise inclusive or
xor ^ bitwise exclusive or
and & bitwise and
- Synopsis
+<b> Synopsis</b>
2 #include <a href="#7.17"><stdatomic.h></a>
C atomic_fetch_key(volatile A *object, M operand);
C atomic_fetch_key_explicit(volatile A *object,
M operand, memory_order order);
- Description
+<b> Description</b>
3 Atomically replaces the value pointed to by object with the result of the computation
applied to the value pointed to by object and the given operand. Memory is affected
according to the value of order. These operations are atomic read-modify-write
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+
+[<a name="p283" href="#p283">page 283</a>] (<a href="#Contents">Contents</a>)
operations (<a href="#5.1.2.4">5.1.2.4</a>). For signed integer types, arithmetic is defined to use two's
complement representation with silent wrap-around on overflow; there are no undefined
results. For address types, the result may be an undefined address, but the operations
otherwise have no undefined behavior.
- Returns
+<b> Returns</b>
4 Atomically, the value pointed to by object immediately before the effects.
5 NOTE The operation of the atomic_fetch and modify generic functions are nearly equivalent to the
operation of the corresponding op= compound assignment operators. The only differences are that the
atomic_flag guard = ATOMIC_FLAG_INIT;
<a name="7.17.8.1" href="#7.17.8.1"><b> 7.17.8.1 The atomic_flag_test_and_set functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.17"><stdatomic.h></a>
bool atomic_flag_test_and_set(
volatile atomic_flag *object);
bool atomic_flag_test_and_set_explicit(
volatile atomic_flag *object, memory_order order);
- Description
+<b> Description</b>
2 Atomically sets the value pointed to by object to true. Memory is affected according
to the value of order. These operations are atomic read-modify-write operations
(<a href="#5.1.2.4">5.1.2.4</a>).
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-
-
-[<a name="#p284" href="p284">page 284</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 Atomically, the value of the object immediately before the effects.
<a name="7.17.8.2" href="#7.17.8.2"><b> 7.17.8.2 The atomic_flag_clear functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.17"><stdatomic.h></a>
void atomic_flag_clear(volatile atomic_flag *object);
void atomic_flag_clear_explicit(
volatile atomic_flag *object, memory_order order);
- Description
+<b> Description</b>
2 The order argument shall not be memory_order_acquire nor
memory_order_acq_rel. Atomically sets the value pointed to by object to false.
Memory is affected according to the value of order.
- Returns
+<b> Returns</b>
3 The atomic_flag_clear functions return no value.
-
-
-
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<a name="7.18" href="#7.18"><b> 7.18 Boolean type and values <stdbool.h></b></a>
1 The header <a href="#7.18"><stdbool.h></a> defines four macros.
__bool_true_false_are_defined
which expands to the integer constant 1.
4 Notwithstanding the provisions of <a href="#7.1.3">7.1.3</a>, a program may undefine and perhaps then
- redefine the macros bool, true, and false.252)
+ redefine the macros bool, true, and false.<sup><a href="#note252"><b>252)</b></a></sup>
-
252) See ''future library directions'' (<a href="#7.30.7">7.30.7</a>).
+
<sup><a name="note252" href="#note252"><b>252)</b></a></sup> See ''future library directions'' (<a href="#7.30.7">7.30.7</a>).
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<a name="7.19" href="#7.19"><b> 7.19 Common definitions <stddef.h></b></a>
1 The header <a href="#7.19"><stddef.h></a> defines the following macros and declares the following types.
greater than that of signed long int unless the implementation supports objects
large enough to make this necessary.
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Forward references: localization (<a href="#7.11">7.11</a>).
-
-
-
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+[<a name="p288" href="#p288">page 288</a>] (<a href="#Contents">Contents</a>)
<a name="7.20" href="#7.20"><b> 7.20 Integer types <stdint.h></b></a>
1 The header <a href="#7.20"><stdint.h></a> declares sets of integer types having specified widths, and
- defines corresponding sets of macros.253) It also defines macros that specify limits of
+ defines corresponding sets of macros.<sup><a href="#note253"><b>253)</b></a></sup> It also defines macros that specify limits of
integer types corresponding to types defined in other standard headers.
2 Types are defined in the following categories:
-- integer types having certain exact widths;
(Some of these types may denote the same type.)
3 Corresponding macros specify limits of the declared types and construct suitable
constants.
-4 For each type described herein that the implementation provides,
254) <a href="#7.20"><stdint.h></a> shall
+4 For each type described herein that the implementation provides,
<sup><a href="#note254"><b>254)</b></a></sup> <a href="#7.20"><stdint.h></a> shall
declare that typedef name and define the associated macros. Conversely, for each type
described herein that the implementation does not provide, <a href="#7.20"><stdint.h></a> shall not
declare that typedef name nor shall it define the associated macros. An implementation
-
253) See ''future library directions'' (<a href="#7.30.8">7.30.8</a>).
- 254) Some of these types may denote implementation-defined extended integer types.
+
<sup><a name="note253" href="#note253"><b>253)</b></a></sup> See ''future library directions'' (<a href="#7.30.8">7.30.8</a>).
+ <sup><a name="note254" href="#note254"><b>254)</b></a></sup> Some of these types may denote implementation-defined extended integer types.
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<a name="7.20.1.1" href="#7.20.1.1"><b> 7.20.1.1 Exact-width integer types</b></a>
1 The typedef name intN_t designates a signed integer type with width N , no padding
int_least64_t uint_least64_t
All other types of this form are optional.
<a name="7.20.1.3" href="#7.20.1.3"><b> 7.20.1.3 Fastest minimum-width integer types</b></a>
-1 Each of the following types designates an integer type that is usually fastest255) to operate
+1 Each of the following types designates an integer type that is usually fastest<sup><a href="#note255"><b>255)</b></a></sup> to operate
with among all integer types that have at least the specified width.
2 The typedef name int_fastN_t designates the fastest signed integer type with a width
of at least N . The typedef name uint_fastN_t designates the fastest unsigned integer
- 255) The designated type is not guaranteed to be fastest for all purposes; if the implementation has no clear
+ <sup><a name="note255" href="#note255"><b>255)</b></a></sup> The designated type is not guaranteed to be fastest for all purposes; if the implementation has no clear
grounds for choosing one type over another, it will simply pick some integer type satisfying the
signedness and width requirements.
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3 The following types are required:
int_fast8_t uint_fast8_t
<a name="7.20.2" href="#7.20.2"><b> 7.20.2 Limits of specified-width integer types</b></a>
1 The following object-like macros specify the minimum and maximum limits of the types *
declared in <a href="#7.20"><stdint.h></a>. Each macro name corresponds to a similar type name in
-<a name="7.20.1" href="#7.20.1"><b> 7.20.1.</b></a>
+ <a href="#7.20.1">7.20.1</a>.
2 Each instance of any defined macro shall be replaced by a constant expression suitable
for use in #if preprocessing directives, and this expression shall have the same type as
would an expression that is an object of the corresponding type converted according to
magnitude (absolute value) than the corresponding value given below, with the same sign,
except where stated to be exactly the given value.
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<a name="7.20.2.1" href="#7.20.2.1"><b> 7.20.2.1 Limits of exact-width integer types</b></a>
1 -- minimum values of exact-width signed integer types
-- maximum value of pointer-holding unsigned integer type
UINTPTR_MAX 216 - 1
-
-
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<a name="7.20.2.5" href="#7.20.2.5"><b> 7.20.2.5 Limits of greatest-width integer types</b></a>
1 -- minimum value of greatest-width signed integer type
promotions. Its implementation-defined value shall be equal to or greater in magnitude
(absolute value) than the corresponding value given below, with the same sign. An
implementation shall define only the macros corresponding to those typedef names it
- actually provides.256)
+ actually provides.<sup><a href="#note256"><b>256)</b></a></sup>
-- limits of ptrdiff_t
PTRDIFF_MIN -65535
PTRDIFF_MAX +65535
- 256) A freestanding implementation need not provide all of these types.
+ <sup><a name="note256" href="#note256"><b>256)</b></a></sup> A freestanding implementation need not provide all of these types.
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WINT_MIN see below
WINT_MAX see below
4 If wchar_t (see <a href="#7.19">7.19</a>) is defined as a signed integer type, the value of WCHAR_MIN
shall be no greater than -127 and the value of WCHAR_MAX shall be no less than 127;
otherwise, wchar_t is defined as an unsigned integer type, and the value of
- WCHAR_MIN shall be 0 and the value of WCHAR_MAX shall be no less than 255.257)
+ WCHAR_MIN shall be 0 and the value of WCHAR_MAX shall be no less than 255.<sup><a href="#note257"><b>257)</b></a></sup>
5 If wint_t (see <a href="#7.28">7.28</a>) is defined as a signed integer type, the value of WINT_MIN shall
be no greater than -32767 and the value of WINT_MAX shall be no less than 32767;
otherwise, wint_t is defined as an unsigned integer type, and the value of WINT_MIN
- 257) The values WCHAR_MIN and WCHAR_MAX do not necessarily correspond to members of the extended
+ <sup><a name="note257" href="#note257"><b>257)</b></a></sup> The values WCHAR_MIN and WCHAR_MAX do not necessarily correspond to members of the extended
character set.
-[<a name="
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+[<a name="
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<a name="7.20.4.2" href="#7.20.4.2"><b> 7.20.4.2 Macros for greatest-width integer constants</b></a>
1 The following macro expands to an integer constant expression having the value specified
by its argument and the type uintmax_t:
UINTMAX_C(value)
-
-
-
-[<a name="#p295" href="p295">page 295</a>] (<a href="#Contents">Contents</a>)
+[<a name="p295" href="#p295">page 295</a>] (<a href="#Contents">Contents</a>)
<a name="7.21" href="#7.21"><b> 7.21 Input/output <stdio.h></b></a>
<a name="7.21.1" href="#7.21.1"><b> 7.21.1 Introduction</b></a>
which expands to an integer constant expression that is the size needed for an array of
char large enough to hold the longest file name string that the implementation
+[<a name="p296" href="#p296">page 296</a>] (<a href="#Contents">Contents</a>)
-
-[<a name="#p296" href="p296">page 296</a>] (<a href="#Contents">Contents</a>)
-
- guarantees can be opened;258)
+ guarantees can be opened;<sup><a href="#note258"><b>258)</b></a></sup>
L_tmpnam
which expands to an integer constant expression that is the size needed for an array of
char large enough to hold a temporary file name string generated by the tmpnam
putwchar, fwprintf, wprintf, vfwprintf, and vwprintf.
- 258) If the implementation imposes no practical limit on the length of file name strings, the value of
+ <sup><a name="note258" href="#note258"><b>258)</b></a></sup> If the implementation imposes no practical limit on the length of file name strings, the value of
FILENAME_MAX should instead be the recommended size of an array intended to hold a file name
string. Of course, file name string contents are subject to other system-specific constraints; therefore
all possible strings of length FILENAME_MAX cannot be expected to be opened successfully.
-[<a name="
#p297" href="p297">page 297</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p297" href="#p297">page 297</a>] (<a href="#Contents">Contents</a>)
-- The wide character input/output functions -- the union of the ungetwc function, the
wide character input functions, and the wide character output functions.
or whether to or from files supported on structured storage devices, are mapped into
logical data streams, whose properties are more uniform than their various inputs and
outputs. Two forms of mapping are supported, for text streams and for binary
- streams.259)
+ streams.<sup><a href="#note259"><b>259)</b></a></sup>
2 A text stream is an ordered sequence of characters composed into lines, each line
consisting of zero or more characters plus a terminating new-line character. Whether the
last line requires a terminating new-line character is implementation-defined. Characters
character input/output function has been applied to a stream without orientation, the
- 259) An implementation need not distinguish between text streams and binary streams. In such an
+ <sup><a name="note259" href="#note259"><b>259)</b></a></sup> An implementation need not distinguish between text streams and binary streams. In such an
implementation, there need be no new-line characters in a text stream nor any limit to the length of a
line.
-[<a name="
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+[<a name="
p298" href="#p298">page 298</a>] (<a href="#Contents">Contents</a>)
stream becomes a wide-oriented stream. Similarly, once a byte input/output function has
been applied to a stream without orientation, the stream becomes a byte-oriented stream.
Only a call to the freopen function or the fwide function can otherwise alter the
- orientation of a stream. (A successful call to freopen removes any orientation.)260)
+ orientation of a stream. (A successful call to freopen removes any orientation.)<sup><a href="#note260"><b>260)</b></a></sup>
5 Byte input/output functions shall not be applied to a wide-oriented stream and wide
character input/output functions shall not be applied to a byte-oriented stream. The
remaining stream operations do not affect, and are not affected by, a stream's orientation,
- 260) The three predefined streams stdin, stdout, and stderr are unoriented at program startup.
+ <sup><a name="note260" href="#note260"><b>260)</b></a></sup> The three predefined streams stdin, stdout, and stderr are unoriented at program startup.
-[<a name="
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+[<a name="
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<a name="7.21.3" href="#7.21.3"><b> 7.21.3 Files</b></a>
1 A stream is associated with an external file (which may be a physical device) by opening
6 The address of the FILE object used to control a stream may be significant; a copy of a
FILE object need not serve in place of the original.
-[<a name="
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+[<a name="
p300" href="#p300">page 300</a>] (<a href="#Contents">Contents</a>)
7 At program startup, three text streams are predefined and need not be opened explicitly
-- standard input (for reading conventional input), standard output (for writing
multibyte characters, generalized as follows:
-- Multibyte encodings within files may contain embedded null bytes (unlike multibyte
encodings valid for use internal to the program).
- -- A file need not begin nor end in the initial shift state.261)
+ -- A file need not begin nor end in the initial shift state.<sup><a href="#note261"><b>261)</b></a></sup>
10 Moreover, the encodings used for multibyte characters may differ among files. Both the
nature and choice of such encodings are implementation-defined.
11 The wide character input functions read multibyte characters from the stream and convert
value passed to the underlying wcrtomb does not correspond to a valid (generalized)
- 261) Setting the file position indicator to end-of-file, as with fseek(file, 0, SEEK_END), has
+ <sup><a name="note261" href="#note261"><b>261)</b></a></sup> Setting the file position indicator to end-of-file, as with fseek(file, 0, SEEK_END), has
undefined behavior for a binary stream (because of possible trailing null characters) or for any stream
with state-dependent encoding that does not assuredly end in the initial shift state.
-[<a name="
#p301" href="p301">page 301</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p301" href="#p301">page 301</a>] (<a href="#Contents">Contents</a>)
multibyte character. The wide character input/output functions and the byte input/output
functions store the value of the macro EILSEQ in errno if and only if an encoding error
(<a href="#7.28.6.3.2">7.28.6.3.2</a>), the wcrtomb function (<a href="#7.28.6.3.3">7.28.6.3.3</a>).
<a name="7.21.4" href="#7.21.4"><b> 7.21.4 Operations on files</b></a>
<a name="7.21.4.1" href="#7.21.4.1"><b> 7.21.4.1 The remove function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int remove(const char *filename);
- Description
+<b> Description</b>
2 The remove function causes the file whose name is the string pointed to by filename
to be no longer accessible by that name. A subsequent attempt to open that file using that
name will fail, unless it is created anew. If the file is open, the behavior of the remove
function is implementation-defined.
- Returns
+<b> Returns</b>
3 The remove function returns zero if the operation succeeds, nonzero if it fails.
<a name="7.21.4.2" href="#7.21.4.2"><b> 7.21.4.2 The rename function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int rename(const char *old, const char *new);
- Description
+<b> Description</b>
2 The rename function causes the file whose name is the string pointed to by old to be
henceforth known by the name given by the string pointed to by new. The file named
old is no longer accessible by that name. If a file named by the string pointed to by new
exists prior to the call to the rename function, the behavior is implementation-defined.
+[<a name="p302" href="#p302">page 302</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p302" href="p302">page 302</a>] (<a href="#Contents">Contents</a>)
-
- Returns
-3 The rename function returns zero if the operation succeeds, nonzero if it fails,262) in
+<b> Returns</b>
+3 The rename function returns zero if the operation succeeds, nonzero if it fails,<sup><a href="#note262"><b>262)</b></a></sup> in
which case if the file existed previously it is still known by its original name.
<a name="7.21.4.3" href="#7.21.4.3"><b> 7.21.4.3 The tmpfile function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
FILE *tmpfile(void);
- Description
+<b> Description</b>
2 The tmpfile function creates a temporary binary file that is different from any other
existing file and that will automatically be removed when it is closed or at program
termination. If the program terminates abnormally, whether an open temporary file is
program (this limit may be shared with tmpnam) and there should be no limit on the
number simultaneously open other than this limit and any limit on the number of open
files (FOPEN_MAX).
- Returns
+<b> Returns</b>
4 The tmpfile function returns a pointer to the stream of the file that it created. If the file
cannot be created, the tmpfile function returns a null pointer.
Forward references: the fopen function (<a href="#7.21.5.3">7.21.5.3</a>).
<a name="7.21.4.4" href="#7.21.4.4"><b> 7.21.4.4 The tmpnam function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
char *tmpnam(char *s);
- Description
+<b> Description</b>
2 The tmpnam function generates a string that is a valid file name and that is not the same
- as the name of an existing file.263) The function is potentially capable of generating at
+ as the name of an existing file.<sup><a href="#note263"><b>263)</b></a></sup> The function is potentially capable of generating at
- 262) Among the reasons the implementation may cause the rename function to fail are that the file is open
+ <sup><a name="note262" href="#note262"><b>262)</b></a></sup> Among the reasons the implementation may cause the rename function to fail are that the file is open
or that it is necessary to copy its contents to effectuate its renaming.
- 263) Files created using strings generated by the tmpnam function are temporary only in the sense that
+ <sup><a name="note263" href="#note263"><b>263)</b></a></sup> Files created using strings generated by the tmpnam function are temporary only in the sense that
their names should not collide with those generated by conventional naming rules for the
implementation. It is still necessary to use the remove function to remove such files when their use
is ended, and before program termination.
-[<a name="
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+[<a name="
p303" href="#p303">page 303</a>] (<a href="#Contents">Contents</a>)
least TMP_MAX different strings, but any or all of them may already be in use by existing
files and thus not be suitable return values.
4 Calls to the tmpnam function with a null pointer argument may introduce data races with
each other. The implementation shall behave as if no library function calls the tmpnam
function.
- Returns
+<b> Returns</b>
5 If no suitable string can be generated, the tmpnam function returns a null pointer.
Otherwise, if the argument is a null pointer, the tmpnam function leaves its result in an
internal static object and returns a pointer to that object (subsequent calls to the tmpnam
6 The value of the macro TMP_MAX shall be at least 25.
<a name="7.21.5" href="#7.21.5"><b> 7.21.5 File access functions</b></a>
<a name="7.21.5.1" href="#7.21.5.1"><b> 7.21.5.1 The fclose function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int fclose(FILE *stream);
- Description
+<b> Description</b>
2 A successful call to the fclose function causes the stream pointed to by stream to be
flushed and the associated file to be closed. Any unwritten buffered data for the stream
are delivered to the host environment to be written to the file; any unread buffered data
are discarded. Whether or not the call succeeds, the stream is disassociated from the file
and any buffer set by the setbuf or setvbuf function is disassociated from the stream
(and deallocated if it was automatically allocated).
- Returns
+<b> Returns</b>
3 The fclose function returns zero if the stream was successfully closed, or EOF if any
errors were detected.
-
-
-
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+[<a name="p304" href="#p304">page 304</a>] (<a href="#Contents">Contents</a>)
<a name="7.21.5.2" href="#7.21.5.2"><b> 7.21.5.2 The fflush function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int fflush(FILE *stream);
- Description
+<b> Description</b>
2 If stream points to an output stream or an update stream in which the most recent
operation was not input, the fflush function causes any unwritten data for that stream
to be delivered to the host environment to be written to the file; otherwise, the behavior is
undefined.
3 If stream is a null pointer, the fflush function performs this flushing action on all
streams for which the behavior is defined above.
- Returns
+<b> Returns</b>
4 The fflush function sets the error indicator for the stream and returns EOF if a write
error occurs, otherwise it returns zero.
Forward references: the fopen function (<a href="#7.21.5.3">7.21.5.3</a>).
<a name="7.21.5.3" href="#7.21.5.3"><b> 7.21.5.3 The fopen function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
FILE *fopen(const char * restrict filename,
const char * restrict mode);
- Description
+<b> Description</b>
2 The fopen function opens the file whose name is the string pointed to by filename,
and associates a stream with it.
3 The argument mode points to a string. If the string is one of the following, the file is
- open in the indicated mode. Otherwise, the behavior is undefined.264)
+ open in the indicated mode. Otherwise, the behavior is undefined.<sup><a href="#note264"><b>264)</b></a></sup>
r open text file for reading
w truncate to zero length or create text file for writing
wx create text file for writing
wb truncate to zero length or create binary file for writing
- 264) If the string begins with one of the above sequences, the implementation might choose to ignore the
+ <sup><a name="note264" href="#note264"><b>264)</b></a></sup> If the string begins with one of the above sequences, the implementation might choose to ignore the
remaining characters, or it might use them to select different kinds of a file (some of which might not
conform to the properties in <a href="#7.21.2">7.21.2</a>).
-[<a name="
#p305" href="p305">page 305</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p305" href="#p305">page 305</a>] (<a href="#Contents">Contents</a>)
wbx create binary file for writing
ab append; open or create binary file for writing at end-of-file
binary stream in some implementations.
8 When opened, a stream is fully buffered if and only if it can be determined not to refer to
an interactive device. The error and end-of-file indicators for the stream are cleared.
- Returns
+<b> Returns</b>
9 The fopen function returns a pointer to the object controlling the stream. If the open
operation fails, fopen returns a null pointer.
Forward references: file positioning functions (<a href="#7.21.9">7.21.9</a>).
-
-
-[<a name="#p306" href="p306">page 306</a>] (<a href="#Contents">Contents</a>)
+[<a name="p306" href="#p306">page 306</a>] (<a href="#Contents">Contents</a>)
<a name="7.21.5.4" href="#7.21.5.4"><b> 7.21.5.4 The freopen function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
FILE *freopen(const char * restrict filename,
const char * restrict mode,
FILE * restrict stream);
- Description
+<b> Description</b>
2 The freopen function opens the file whose name is the string pointed to by filename
and associates the stream pointed to by stream with it. The mode argument is used just
- as in the fopen function.265)
+ as in the fopen function.<sup><a href="#note265"><b>265)</b></a></sup>
3 If filename is a null pointer, the freopen function attempts to change the mode of
the stream to that specified by mode, as if the name of the file currently associated with
the stream had been used. It is implementation-defined which changes of mode are
4 The freopen function first attempts to close any file that is associated with the specified
stream. Failure to close the file is ignored. The error and end-of-file indicators for the
stream are cleared.
- Returns
+<b> Returns</b>
5 The freopen function returns a null pointer if the open operation fails. Otherwise,
freopen returns the value of stream.
<a name="7.21.5.5" href="#7.21.5.5"><b> 7.21.5.5 The setbuf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
void setbuf(FILE * restrict stream,
char * restrict buf);
- Description
+<b> Description</b>
2 Except that it returns no value, the setbuf function is equivalent to the setvbuf
function invoked with the values _IOFBF for mode and BUFSIZ for size, or (if buf
is a null pointer), with the value _IONBF for mode.
- 265) The primary use of the freopen function is to change the file associated with a standard text stream
+ <sup><a name="note265" href="#note265"><b>265)</b></a></sup> The primary use of the freopen function is to change the file associated with a standard text stream
(stderr, stdin, or stdout), as those identifiers need not be modifiable lvalues to which the value
returned by the fopen function may be assigned.
-[<a name="
#p307" href="p307">page 307</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p307" href="#p307">page 307</a>] (<a href="#Contents">Contents</a>)
- Returns
+<b> Returns</b>
3 The setbuf function returns no value.
Forward references: the setvbuf function (<a href="#7.21.5.6">7.21.5.6</a>).
<a name="7.21.5.6" href="#7.21.5.6"><b> 7.21.5.6 The setvbuf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int setvbuf(FILE * restrict stream,
char * restrict buf,
int mode, size_t size);
- Description
+<b> Description</b>
2 The setvbuf function may be used only after the stream pointed to by stream has
been associated with an open file and before any other operation (other than an
unsuccessful call to setvbuf) is performed on the stream. The argument mode
determines how stream will be buffered, as follows: _IOFBF causes input/output to be
fully buffered; _IOLBF causes input/output to be line buffered; _IONBF causes
input/output to be unbuffered. If buf is not a null pointer, the array it points to may be
- used instead of a buffer allocated by the setvbuf function266) and the argument size
+ used instead of a buffer allocated by the setvbuf function<sup><a href="#note266"><b>266)</b></a></sup> and the argument size
specifies the size of the array; otherwise, size may determine the size of a buffer
allocated by the setvbuf function. The contents of the array at any time are
indeterminate.
- Returns
+<b> Returns</b>
3 The setvbuf function returns zero on success, or nonzero if an invalid value is given
for mode or if the request cannot be honored.
- 266) The buffer has to have a lifetime at least as great as the open stream, so the stream should be closed
+ <sup><a name="note266" href="#note266"><b>266)</b></a></sup> The buffer has to have a lifetime at least as great as the open stream, so the stream should be closed
before a buffer that has automatic storage duration is deallocated upon block exit.
-[<a name="
#p308" href="p308">page 308</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p308" href="#p308">page 308</a>] (<a href="#Contents">Contents</a>)
<a name="7.21.6" href="#7.21.6"><b> 7.21.6 Formatted input/output functions</b></a>
1 The formatted input/output functions shall behave as if there is a sequence point after the
- actions associated with each specifier.267)
+ actions associated with each specifier.<sup><a href="#note267"><b>267)</b></a></sup>
<a name="7.21.6.1" href="#7.21.6.1"><b> 7.21.6.1 The fprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int fprintf(FILE * restrict stream,
const char * restrict format, ...);
- Description
+<b> Description</b>
2 The fprintf function writes output to the stream pointed to by stream, under control
of the string pointed to by format that specifies how subsequent arguments are
converted for output. If there are insufficient arguments for the format, the behavior is
-- An optional minimum field width. If the converted value has fewer characters than the
field width, it is padded with spaces (by default) on the left (or right, if the left
adjustment flag, described later, has been given) to the field width. The field width
- takes the form of an asterisk * (described later) or a nonnegative decimal integer.268)
+ takes the form of an asterisk * (described later) or a nonnegative decimal integer.<sup><a href="#note268"><b>268)</b></a></sup>
-- An optional precision that gives the minimum number of digits to appear for the d, i,
o, u, x, and X conversions, the number of digits to appear after the decimal-point
character for a, A, e, E, f, and F conversions, the maximum number of significant
digits for the g and G conversions, or the maximum number of bytes to be written for
- 267) The fprintf functions perform writes to memory for the %n specifier.
- 268) Note that 0 is taken as a flag, not as the beginning of a field width.
+ <sup><a name="note267" href="#note267"><b>267)</b></a></sup> The fprintf functions perform writes to memory for the %n specifier.
+ <sup><a name="note268" href="#note268"><b>268)</b></a></sup> Note that 0 is taken as a flag, not as the beginning of a field width.
-[<a name="
#p309" href="p309">page 309</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p309" href="#p309">page 309</a>] (<a href="#Contents">Contents</a>)
s conversions. The precision takes the form of a period (.) followed either by an
asterisk * (described later) or by an optional decimal integer; if only the period is
this flag is not specified.)
+ The result of a signed conversion always begins with a plus or minus sign. (It
begins with a sign only when a negative value is converted if this flag is not
- specified.)269)
+ specified.)<sup><a href="#note269"><b>269)</b></a></sup>
space If the first character of a signed conversion is not a sign, or if a signed conversion
results in no characters, a space is prefixed to the result. If the space and + flags
both appear, the space flag is ignored.
0 and - flags both appear, the 0 flag is ignored. For d, i, o, u, x, and X
- 269) The results of all floating conversions of a negative zero, and of negative values that round to zero,
+ <sup><a name="note269" href="#note269"><b>269)</b></a></sup> The results of all floating conversions of a negative zero, and of negative values that round to zero,
include a minus sign.
-[<a name="
#p310" href="p310">page 310</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p310" href="#p310">page 310</a>] (<a href="#Contents">Contents</a>)
conversions, if a precision is specified, the 0 flag is ignored. For other
conversions, the behavior is undefined.
following n conversion specifier applies to a pointer to a ptrdiff_t
argument.
-
-[<a name="#p311" href="p311">page 311</a>] (<a href="#Contents">Contents</a>)
+[<a name="p311" href="#p311">page 311</a>] (<a href="#Contents">Contents</a>)
L Specifies that a following a, A, e, E, f, F, g, or G conversion specifier
applies to a long double argument.
[-]nan or [-]nan(n-char-sequence) -- which style, and the meaning of
any n-char-sequence, is implementation-defined. The F conversion specifier
produces INF, INFINITY, or NAN instead of inf, infinity, or nan,
- respectively.270)
+ respectively.<sup><a href="#note270"><b>270)</b></a></sup>
e,E A double argument representing a floating-point number is converted in the
style [-]d.ddd e(+-)dd, where there is one digit (which is nonzero if the
argument is nonzero) before the decimal-point character and the number of
digits after it is equal to the precision; if the precision is missing, it is taken as
- 270) When applied to infinite and NaN values, the -, +, and space flag characters have their usual meaning;
+ <sup><a name="note270" href="#note270"><b>270)</b></a></sup> When applied to infinite and NaN values, the -, +, and space flag characters have their usual meaning;
the # and 0 flag characters have no effect.
-[<a name="
#p312" href="p312">page 312</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p312" href="#p312">page 312</a>] (<a href="#Contents">Contents</a>)
6; if the precision is zero and the # flag is not specified, no decimal-point
character appears. The value is rounded to the appropriate number of digits.
a,A A double argument representing a floating-point number is converted in the
style [-]0xh.hhhh p(+-)d, where there is one hexadecimal digit (which is
nonzero if the argument is a normalized floating-point number and is
- otherwise unspecified) before the decimal-point character271) and the number
+ otherwise unspecified) before the decimal-point character<sup><a href="#note271"><b>271)</b></a></sup> and the number
of hexadecimal digits after it is equal to the precision; if the precision is
missing and FLT_RADIX is a power of 2, then the precision is sufficient for
an exact representation of the value; if the precision is missing and
-271) Binary implementations can choose the hexadecimal digit to the left of the decimal-point character so
+<sup><a name="note271" href="#note271"><b>271)</b></a></sup> Binary implementations can choose the hexadecimal digit to the left of the decimal-point character so
that subsequent digits align to nibble (4-bit) boundaries.
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+[<a name="
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- distinguish272) values of type double, except that trailing zeros may be
+ distinguish<sup><a href="#note272"><b>272)</b></a></sup> values of type double, except that trailing zeros may be
omitted; if the precision is zero and the # flag is not specified, no decimal-
point character appears. The letters abcdef are used for a conversion and
the letters ABCDEF for A conversion. The A conversion specifier produces a
containing the wint_t argument to the lc conversion specification and the
second a null wide character.
s If no l length modifier is present, the argument shall be a pointer to the initial
- element of an array of character type.273) Characters from the array are
+ element of an array of character type.<sup><a href="#note273"><b>273)</b></a></sup> Characters from the array are
written up to (but not including) the terminating null character. If the
precision is specified, no more than that many bytes are written. If the
precision is not specified or is greater than the size of the array, the array shall
written (including shift sequences, if any), and the array shall contain a null
wide character if, to equal the multibyte character sequence length given by
-272) The precision p is sufficient to distinguish values of the source type if 16 p-1 > b n where b is
+<sup><a name="note272" href="#note272"><b>272)</b></a></sup> The precision p is sufficient to distinguish values of the source type if 16 p-1 > b n where b is
FLT_RADIX and n is the number of base-b digits in the significand of the source type. A smaller p
might suffice depending on the implementation's scheme for determining the digit to the left of the
decimal-point character.
-273) No special provisions are made for multibyte characters.
+<sup><a name="note273" href="#note273"><b>273)</b></a></sup> No special provisions are made for multibyte characters.
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the precision, the function would need to access a wide character one past the
- end of the array. In no case is a partial multibyte character written.274)
+ end of the array. In no case is a partial multibyte character written.<sup><a href="#note274"><b>274)</b></a></sup>
p The argument shall be a pointer to void. The value of the pointer is
converted to a sequence of printing characters, in an implementation-defined
manner.
undefined.
% A % character is written. No argument is converted. The complete
conversion specification shall be %%.
-9 If a conversion specification is invalid, the behavior is undefined.275) If any argument is
+9 If a conversion specification is invalid, the behavior is undefined.<sup><a href="#note275"><b>275)</b></a></sup> If any argument is
not the correct type for the corresponding conversion specification, the behavior is
undefined.
10 In no case does a nonexistent or small field width cause truncation of a field; if the result
in hexadecimal floating style with the given precision, with the extra stipulation that the
error should have a correct sign for the current rounding direction.
13 For e, E, f, F, g, and G conversions, if the number of significant decimal digits is at most
- DECIMAL_DIG, then the result should be correctly rounded.276) If the number of
+ DECIMAL_DIG, then the result should be correctly rounded.<sup><a href="#note276"><b>276)</b></a></sup> If the number of
significant decimal digits is more than DECIMAL_DIG but the source value is exactly
representable with DECIMAL_DIG digits, then the result should be an exact
representation with trailing zeros. Otherwise, the source value is bounded by two
adjacent decimal strings L < U, both having DECIMAL_DIG significant digits; the value
- 274) Redundant shift sequences may result if multibyte characters have a state-dependent encoding.
-
275) See ''future library directions'' (<a href="#7.30.9">7.30.9</a>).
- 276) For binary-to-decimal conversion, the result format's values are the numbers representable with the
+ <sup><a name="note274" href="#note274"><b>274)</b></a></sup> Redundant shift sequences may result if multibyte characters have a state-dependent encoding.
+
<sup><a name="note275" href="#note275"><b>275)</b></a></sup> See ''future library directions'' (<a href="#7.30.9">7.30.9</a>).
+ <sup><a name="note276" href="#note276"><b>276)</b></a></sup> For binary-to-decimal conversion, the result format's values are the numbers representable with the
given format specifier. The number of significant digits is determined by the format specifier, and in
the case of fixed-point conversion by the source value as well.
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of the resultant decimal string D should satisfy L <= D <= U, with the extra stipulation that
the error should have a correct sign for the current rounding direction.
- Returns
+<b> Returns</b>
14 The fprintf function returns the number of characters transmitted, or a negative value
if an output or encoding error occurred.
Environmental limits
int day, hour, min;
fprintf(stdout, "%s, %s %d, %.2d:%.2d\n",
weekday, month, day, hour, min);
- fprintf(stdout, "pi = %.5f\n", 4 * atan(<a href="#1.0">1.0</a>));
+ fprintf(stdout, "pi = %.5f\n", 4 * atan(1.0));
17 EXAMPLE 2 In this example, multibyte characters do not have a state-dependent encoding, and the
members of the extended character set that consist of more than one byte each consist of exactly two bytes,
Forward references: conversion state (<a href="#7.28.6">7.28.6</a>), the wcrtomb function (<a href="#7.28.6.3.3">7.28.6.3.3</a>).
-
-
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+[<a name="p316" href="#p316">page 316</a>] (<a href="#Contents">Contents</a>)
<a name="7.21.6.2" href="#7.21.6.2"><b> 7.21.6.2 The fscanf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int fscanf(FILE * restrict stream,
const char * restrict format, ...);
- Description
+<b> Description</b>
2 The fscanf function reads input from the stream pointed to by stream, under control
of the string pointed to by format that specifies the admissible input sequences and how
they are to be converted for assignment, using subsequent arguments as pointers to the
7 A directive that is a conversion specification defines a set of matching input sequences, as
described below for each specifier. A conversion specification is executed in the
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following steps:
8 Input white-space characters (as specified by the isspace function) are skipped, unless
- the specification includes a [, c, or n specifier.277)
+ the specification includes a [, c, or n specifier.<sup><a href="#note277"><b>277)</b></a></sup>
9 An input item is read from the stream, unless the specification includes an n specifier. An
input item is defined as the longest sequence of input characters which does not exceed
- any specified field width and which is, or is a prefix of, a matching input sequence.278)
+ any specified field width and which is, or is a prefix of, a matching input sequence.<sup><a href="#note278"><b>278)</b></a></sup>
The first character, if any, after the input item remains unread. If the length of the input
item is zero, the execution of the directive fails; this condition is a matching failure unless
end-of-file, an encoding error, or a read error prevented input from the stream, in which
- 277) These white-space characters are not counted against a specified field width.
- 278) fscanf pushes back at most one input character onto the input stream. Therefore, some sequences
+ <sup><a name="note277" href="#note277"><b>277)</b></a></sup> These white-space characters are not counted against a specified field width.
+ <sup><a name="note278" href="#note278"><b>278)</b></a></sup> fscanf pushes back at most one input character onto the input stream. Therefore, some sequences
that are acceptable to strtod, strtol, etc., are unacceptable to fscanf.
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j Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
to an argument with type pointer to intmax_t or uintmax_t.
format is the same as expected for the subject sequence of the strtod
function. The corresponding argument shall be a pointer to floating.
-
-[<a name="#p319" href="p319">page 319</a>] (<a href="#Contents">Contents</a>)
+[<a name="p319" href="#p319">page 319</a>] (<a href="#Contents">Contents</a>)
c Matches a sequence of characters of exactly the number specified by the field
- width (1 if no field width is present in the directive).279)
+ width (1 if no field width is present in the directive).<sup><a href="#note279"><b>279)</b></a></sup>
If no l length modifier is present, the corresponding argument shall be a
pointer to the initial element of a character array large enough to accept the
sequence. No null character is added.
converted to a wide character as if by a call to the mbrtowc function, with
the conversion state described by an mbstate_t object initialized to zero
-279) No special provisions are made for multibyte characters in the matching rules used by the c, s, and [
+<sup><a name="note279" href="#note279"><b>279)</b></a></sup> No special provisions are made for multibyte characters in the matching rules used by the c, s, and [
conversion specifiers -- the extent of the input field is determined on a byte-by-byte basis. The
resulting field is nevertheless a sequence of multibyte characters that begins in the initial shift state.
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before the first multibyte character is converted. The corresponding argument
shall be a pointer to the initial element of an array of wchar_t large enough
suppressing character or a field width, the behavior is undefined.
% Matches a single % character; no conversion or assignment occurs. The
complete conversion specification shall be %%.
-13 If a conversion specification is invalid, the behavior is undefined.280)
+13 If a conversion specification is invalid, the behavior is undefined.<sup><a href="#note280"><b>280)</b></a></sup>
14 The conversion specifiers A, E, F, G, and X are also valid and behave the same as,
respectively, a, e, f, g, and x.
-
280) See ''future library directions'' (<a href="#7.30.9">7.30.9</a>).
+
<sup><a name="note280" href="#note280"><b>280)</b></a></sup> See ''future library directions'' (<a href="#7.30.9">7.30.9</a>).
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+[<a name="
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15 Trailing white space (including new-line characters) is left unread unless matched by a
directive. The success of literal matches and suppressed assignments is not directly
determinable other than via the %n directive.
- Returns
+<b> Returns</b>
16 The fscanf function returns the value of the macro EOF if an input failure occurs
before the first conversion (if any) has completed. Otherwise, the function returns the
number of input items assigned, which can be fewer than provided for, or even zero, in
dirt
100ergs of energy
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the execution of the above example will be analogous to the following assignments:
quant = 2; strcpy(units, "quarts"); strcpy(item, "oil");
terminating null wide character.
25 However, the call:
-
-
-
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+[<a name="p323" href="#p323">page 323</a>] (<a href="#Contents">Contents</a>)
#include <a href="#7.21"><stdio.h></a>
#include <a href="#7.19"><stddef.h></a>
strtol, strtoll, strtoul, and strtoull functions (<a href="#7.22.1.4">7.22.1.4</a>), conversion state
(<a href="#7.28.6">7.28.6</a>), the wcrtomb function (<a href="#7.28.6.3.3">7.28.6.3.3</a>).
<a name="7.21.6.3" href="#7.21.6.3"><b> 7.21.6.3 The printf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int printf(const char * restrict format, ...);
- Description
+<b> Description</b>
2 The printf function is equivalent to fprintf with the argument stdout interposed
before the arguments to printf.
- Returns
+<b> Returns</b>
3 The printf function returns the number of characters transmitted, or a negative value if
an output or encoding error occurred.
<a name="7.21.6.4" href="#7.21.6.4"><b> 7.21.6.4 The scanf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int scanf(const char * restrict format, ...);
- Description
+<b> Description</b>
2 The scanf function is equivalent to fscanf with the argument stdin interposed
before the arguments to scanf.
+[<a name="p324" href="#p324">page 324</a>] (<a href="#Contents">Contents</a>)
-
-[<a name="#p324" href="p324">page 324</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The scanf function returns the value of the macro EOF if an input failure occurs before
the first conversion (if any) has completed. Otherwise, the scanf function returns the
number of input items assigned, which can be fewer than provided for, or even zero, in
the event of an early matching failure.
<a name="7.21.6.5" href="#7.21.6.5"><b> 7.21.6.5 The snprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int snprintf(char * restrict s, size_t n,
const char * restrict format, ...);
- Description
+<b> Description</b>
2 The snprintf function is equivalent to fprintf, except that the output is written into
an array (specified by argument s) rather than to a stream. If n is zero, nothing is written,
and s may be a null pointer. Otherwise, output characters beyond the n-1st are
discarded rather than being written to the array, and a null character is written at the end
of the characters actually written into the array. If copying takes place between objects
that overlap, the behavior is undefined.
- Returns
+<b> Returns</b>
3 The snprintf function returns the number of characters that would have been written
had n been sufficiently large, not counting the terminating null character, or a negative
value if an encoding error occurred. Thus, the null-terminated output has been
completely written if and only if the returned value is nonnegative and less than n.
<a name="7.21.6.6" href="#7.21.6.6"><b> 7.21.6.6 The sprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int sprintf(char * restrict s,
const char * restrict format, ...);
- Description
+<b> Description</b>
2 The sprintf function is equivalent to fprintf, except that the output is written into
an array (specified by the argument s) rather than to a stream. A null character is written
at the end of the characters written; it is not counted as part of the returned value. If
copying takes place between objects that overlap, the behavior is undefined.
- Returns
+<b> Returns</b>
3 The sprintf function returns the number of characters written in the array, not
counting the terminating null character, or a negative value if an encoding error occurred.
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<a name="7.21.6.7" href="#7.21.6.7"><b> 7.21.6.7 The sscanf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int sscanf(const char * restrict s,
const char * restrict format, ...);
- Description
+<b> Description</b>
2 The sscanf function is equivalent to fscanf, except that input is obtained from a
string (specified by the argument s) rather than from a stream. Reaching the end of the
string is equivalent to encountering end-of-file for the fscanf function. If copying
takes place between objects that overlap, the behavior is undefined.
- Returns
+<b> Returns</b>
3 The sscanf function returns the value of the macro EOF if an input failure occurs
before the first conversion (if any) has completed. Otherwise, the sscanf function
returns the number of input items assigned, which can be fewer than provided for, or even
zero, in the event of an early matching failure.
<a name="7.21.6.8" href="#7.21.6.8"><b> 7.21.6.8 The vfprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
int vfprintf(FILE * restrict stream,
const char * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vfprintf function is equivalent to fprintf, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vfprintf function does not invoke the
- va_end macro.281)
- Returns
+ va_end macro.<sup><a href="#note281"><b>281)</b></a></sup>
+<b> Returns</b>
3 The vfprintf function returns the number of characters transmitted, or a negative
value if an output or encoding error occurred.
4 EXAMPLE The following shows the use of the vfprintf function in a general error-reporting routine.
- 281) As the functions vfprintf, vfscanf, vprintf, vscanf, vsnprintf, vsprintf, and
+ <sup><a name="note281" href="#note281"><b>281)</b></a></sup> As the functions vfprintf, vfscanf, vprintf, vscanf, vsnprintf, vsprintf, and
vsscanf invoke the va_arg macro, the value of arg after the return is indeterminate.
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#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
}
<a name="7.21.6.9" href="#7.21.6.9"><b> 7.21.6.9 The vfscanf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
int vfscanf(FILE * restrict stream,
const char * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vfscanf function is equivalent to fscanf, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vfscanf function does not invoke the
va_end macro.281)
- Returns
+<b> Returns</b>
3 The vfscanf function returns the value of the macro EOF if an input failure occurs
before the first conversion (if any) has completed. Otherwise, the vfscanf function
returns the number of input items assigned, which can be fewer than provided for, or even
zero, in the event of an early matching failure.
<a name="7.21.6.10" href="#7.21.6.10"><b> 7.21.6.10 The vprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
int vprintf(const char * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vprintf function is equivalent to printf, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
-[<a name="
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+[<a name="
p327" href="#p327">page 327</a>] (<a href="#Contents">Contents</a>)
possibly subsequent va_arg calls). The vprintf function does not invoke the
va_end macro.281)
- Returns
+<b> Returns</b>
3 The vprintf function returns the number of characters transmitted, or a negative value
if an output or encoding error occurred.
<a name="7.21.6.11" href="#7.21.6.11"><b> 7.21.6.11 The vscanf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
int vscanf(const char * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vscanf function is equivalent to scanf, with the variable argument list replaced
by arg, which shall have been initialized by the va_start macro (and possibly
subsequent va_arg calls). The vscanf function does not invoke the va_end
macro.281)
- Returns
+<b> Returns</b>
3 The vscanf function returns the value of the macro EOF if an input failure occurs
before the first conversion (if any) has completed. Otherwise, the vscanf function
returns the number of input items assigned, which can be fewer than provided for, or even
zero, in the event of an early matching failure.
<a name="7.21.6.12" href="#7.21.6.12"><b> 7.21.6.12 The vsnprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
int vsnprintf(char * restrict s, size_t n,
const char * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vsnprintf function is equivalent to snprintf, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vsnprintf function does not invoke the
va_end macro.281) If copying takes place between objects that overlap, the behavior is
undefined.
+[<a name="p328" href="#p328">page 328</a>] (<a href="#Contents">Contents</a>)
-
-[<a name="#p328" href="p328">page 328</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The vsnprintf function returns the number of characters that would have been written
had n been sufficiently large, not counting the terminating null character, or a negative
value if an encoding error occurred. Thus, the null-terminated output has been
completely written if and only if the returned value is nonnegative and less than n.
<a name="7.21.6.13" href="#7.21.6.13"><b> 7.21.6.13 The vsprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
int vsprintf(char * restrict s,
const char * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vsprintf function is equivalent to sprintf, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vsprintf function does not invoke the
va_end macro.281) If copying takes place between objects that overlap, the behavior is
undefined.
- Returns
+<b> Returns</b>
3 The vsprintf function returns the number of characters written in the array, not
counting the terminating null character, or a negative value if an encoding error occurred.
<a name="7.21.6.14" href="#7.21.6.14"><b> 7.21.6.14 The vsscanf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
int vsscanf(const char * restrict s,
const char * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vsscanf function is equivalent to sscanf, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vsscanf function does not invoke the
va_end macro.281)
- Returns
+<b> Returns</b>
3 The vsscanf function returns the value of the macro EOF if an input failure occurs
before the first conversion (if any) has completed. Otherwise, the vsscanf function
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+
+[<a name="p329" href="#p329">page 329</a>] (<a href="#Contents">Contents</a>)
returns the number of input items assigned, which can be fewer than provided for, or even
zero, in the event of an early matching failure.
<a name="7.21.7" href="#7.21.7"><b> 7.21.7 Character input/output functions</b></a>
<a name="7.21.7.1" href="#7.21.7.1"><b> 7.21.7.1 The fgetc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int fgetc(FILE *stream);
- Description
+<b> Description</b>
2 If the end-of-file indicator for the input stream pointed to by stream is not set and a
next character is present, the fgetc function obtains that character as an unsigned
char converted to an int and advances the associated file position indicator for the
stream (if defined).
- Returns
+<b> Returns</b>
3 If the end-of-file indicator for the stream is set, or if the stream is at end-of-file, the end-
of-file indicator for the stream is set and the fgetc function returns EOF. Otherwise, the
fgetc function returns the next character from the input stream pointed to by stream.
If a read error occurs, the error indicator for the stream is set and the fgetc function
- returns EOF.282)
+ returns EOF.<sup><a href="#note282"><b>282)</b></a></sup>
<a name="7.21.7.2" href="#7.21.7.2"><b> 7.21.7.2 The fgets function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
char *fgets(char * restrict s, int n,
FILE * restrict stream);
- Description
+<b> Description</b>
2 The fgets function reads at most one less than the number of characters specified by n
from the stream pointed to by stream into the array pointed to by s. No additional
characters are read after a new-line character (which is retained) or after end-of-file. A
null character is written immediately after the last character read into the array.
- Returns
+<b> Returns</b>
3 The fgets function returns s if successful. If end-of-file is encountered and no
characters have been read into the array, the contents of the array remain unchanged and a
null pointer is returned. If a read error occurs during the operation, the array contents are
indeterminate and a null pointer is returned.
- 282) An end-of-file and a read error can be distinguished by use of the feof and ferror functions.
+ <sup><a name="note282" href="#note282"><b>282)</b></a></sup> An end-of-file and a read error can be distinguished by use of the feof and ferror functions.
-[<a name="
#p330" href="p330">page 330</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p330" href="#p330">page 330</a>] (<a href="#Contents">Contents</a>)
<a name="7.21.7.3" href="#7.21.7.3"><b> 7.21.7.3 The fputc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int fputc(int c, FILE *stream);
- Description
+<b> Description</b>
2 The fputc function writes the character specified by c (converted to an unsigned
char) to the output stream pointed to by stream, at the position indicated by the
associated file position indicator for the stream (if defined), and advances the indicator
appropriately. If the file cannot support positioning requests, or if the stream was opened
with append mode, the character is appended to the output stream.
- Returns
+<b> Returns</b>
3 The fputc function returns the character written. If a write error occurs, the error
indicator for the stream is set and fputc returns EOF.
<a name="7.21.7.4" href="#7.21.7.4"><b> 7.21.7.4 The fputs function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int fputs(const char * restrict s,
FILE * restrict stream);
- Description
+<b> Description</b>
2 The fputs function writes the string pointed to by s to the stream pointed to by
stream. The terminating null character is not written.
- Returns
+<b> Returns</b>
3 The fputs function returns EOF if a write error occurs; otherwise it returns a
nonnegative value.
<a name="7.21.7.5" href="#7.21.7.5"><b> 7.21.7.5 The getc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int getc(FILE *stream);
- Description
+<b> Description</b>
2 The getc function is equivalent to fgetc, except that if it is implemented as a macro, it
may evaluate stream more than once, so the argument should never be an expression
with side effects.
+[<a name="p331" href="#p331">page 331</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p331" href="p331">page 331</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The getc function returns the next character from the input stream pointed to by
stream. If the stream is at end-of-file, the end-of-file indicator for the stream is set and
getc returns EOF. If a read error occurs, the error indicator for the stream is set and
getc returns EOF.
<a name="7.21.7.6" href="#7.21.7.6"><b> 7.21.7.6 The getchar function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int getchar(void);
- Description
+<b> Description</b>
2 The getchar function is equivalent to getc with the argument stdin.
- Returns
+<b> Returns</b>
3 The getchar function returns the next character from the input stream pointed to by
stdin. If the stream is at end-of-file, the end-of-file indicator for the stream is set and
getchar returns EOF. If a read error occurs, the error indicator for the stream is set and
getchar returns EOF. *
<a name="7.21.7.7" href="#7.21.7.7"><b> 7.21.7.7 The putc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int putc(int c, FILE *stream);
- Description
+<b> Description</b>
2 The putc function is equivalent to fputc, except that if it is implemented as a macro, it
may evaluate stream more than once, so that argument should never be an expression
with side effects.
- Returns
+<b> Returns</b>
3 The putc function returns the character written. If a write error occurs, the error
indicator for the stream is set and putc returns EOF.
<a name="7.21.7.8" href="#7.21.7.8"><b> 7.21.7.8 The putchar function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int putchar(int c);
- Description
+<b> Description</b>
2 The putchar function is equivalent to putc with the second argument stdout.
+[<a name="p332" href="#p332">page 332</a>] (<a href="#Contents">Contents</a>)
-[<a name="#p332" href="p332">page 332</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The putchar function returns the character written. If a write error occurs, the error
indicator for the stream is set and putchar returns EOF.
<a name="7.21.7.9" href="#7.21.7.9"><b> 7.21.7.9 The puts function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int puts(const char *s);
- Description
+<b> Description</b>
2 The puts function writes the string pointed to by s to the stream pointed to by stdout,
and appends a new-line character to the output. The terminating null character is not
written.
- Returns
+<b> Returns</b>
3 The puts function returns EOF if a write error occurs; otherwise it returns a nonnegative
value.
<a name="7.21.7.10" href="#7.21.7.10"><b> 7.21.7.10 The ungetc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int ungetc(int c, FILE *stream);
- Description
+<b> Description</b>
2 The ungetc function pushes the character specified by c (converted to an unsigned
char) back onto the input stream pointed to by stream. Pushed-back characters will be
returned by subsequent reads on that stream in the reverse order of their pushing. A
back. For a text stream, the value of its file position indicator after a successful call to the
ungetc function is unspecified until all pushed-back characters are read or discarded.
-[<a name="
#p333" href="p333">page 333</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p333" href="#p333">page 333</a>] (<a href="#Contents">Contents</a>)
For a binary stream, its file position indicator is decremented by each successful call to
the ungetc function; if its value was zero before a call, it is indeterminate after the
- call.283)
- Returns
+ call.<sup><a href="#note283"><b>283)</b></a></sup>
+<b> Returns</b>
6 The ungetc function returns the character pushed back after conversion, or EOF if the
operation fails.
Forward references: file positioning functions (<a href="#7.21.9">7.21.9</a>).
<a name="7.21.8" href="#7.21.8"><b> 7.21.8 Direct input/output functions</b></a>
<a name="7.21.8.1" href="#7.21.8.1"><b> 7.21.8.1 The fread function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
size_t fread(void * restrict ptr,
size_t size, size_t nmemb,
FILE * restrict stream);
- Description
+<b> Description</b>
2 The fread function reads, into the array pointed to by ptr, up to nmemb elements
whose size is specified by size, from the stream pointed to by stream. For each
object, size calls are made to the fgetc function and the results stored, in the order
indicator for the stream (if defined) is advanced by the number of characters successfully
read. If an error occurs, the resulting value of the file position indicator for the stream is
indeterminate. If a partial element is read, its value is indeterminate.
- Returns
+<b> Returns</b>
3 The fread function returns the number of elements successfully read, which may be
less than nmemb if a read error or end-of-file is encountered. If size or nmemb is zero,
fread returns zero and the contents of the array and the state of the stream remain
-
283) See ''future library directions'' (<a href="#7.30.9">7.30.9</a>).
+
<sup><a name="note283" href="#note283"><b>283)</b></a></sup> See ''future library directions'' (<a href="#7.30.9">7.30.9</a>).
-[<a name="
#p334" href="p334">page 334</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p334" href="#p334">page 334</a>] (<a href="#Contents">Contents</a>)
<a name="7.21.8.2" href="#7.21.8.2"><b> 7.21.8.2 The fwrite function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
size_t fwrite(const void * restrict ptr,
size_t size, size_t nmemb,
FILE * restrict stream);
- Description
+<b> Description</b>
2 The fwrite function writes, from the array pointed to by ptr, up to nmemb elements
whose size is specified by size, to the stream pointed to by stream. For each object,
size calls are made to the fputc function, taking the values (in order) from an array of
stream (if defined) is advanced by the number of characters successfully written. If an
error occurs, the resulting value of the file position indicator for the stream is
indeterminate.
- Returns
+<b> Returns</b>
3 The fwrite function returns the number of elements successfully written, which will be
less than nmemb only if a write error is encountered. If size or nmemb is zero,
fwrite returns zero and the state of the stream remains unchanged.
<a name="7.21.9" href="#7.21.9"><b> 7.21.9 File positioning functions</b></a>
<a name="7.21.9.1" href="#7.21.9.1"><b> 7.21.9.1 The fgetpos function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int fgetpos(FILE * restrict stream,
fpos_t * restrict pos);
- Description
+<b> Description</b>
2 The fgetpos function stores the current values of the parse state (if any) and file
position indicator for the stream pointed to by stream in the object pointed to by pos.
The values stored contain unspecified information usable by the fsetpos function for
repositioning the stream to its position at the time of the call to the fgetpos function.
- Returns
+<b> Returns</b>
3 If successful, the fgetpos function returns zero; on failure, the fgetpos function
returns nonzero and stores an implementation-defined positive value in errno.
Forward references: the fsetpos function (<a href="#7.21.9.3">7.21.9.3</a>).
-
-
-
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+[<a name="p335" href="#p335">page 335</a>] (<a href="#Contents">Contents</a>)
<a name="7.21.9.2" href="#7.21.9.2"><b> 7.21.9.2 The fseek function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int fseek(FILE *stream, long int offset, int whence);
- Description
+<b> Description</b>
2 The fseek function sets the file position indicator for the stream pointed to by stream.
If a read or write error occurs, the error indicator for the stream is set and fseek fails.
3 For a binary stream, the new position, measured in characters from the beginning of the
effects of the ungetc function on the stream, clears the end-of-file indicator for the
stream, and then establishes the new position. After a successful fseek call, the next
operation on an update stream may be either input or output.
- Returns
+<b> Returns</b>
6 The fseek function returns nonzero only for a request that cannot be satisfied.
Forward references: the ftell function (<a href="#7.21.9.4">7.21.9.4</a>).
<a name="7.21.9.3" href="#7.21.9.3"><b> 7.21.9.3 The fsetpos function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int fsetpos(FILE *stream, const fpos_t *pos);
- Description
+<b> Description</b>
2 The fsetpos function sets the mbstate_t object (if any) and file position indicator
for the stream pointed to by stream according to the value of the object pointed to by
pos, which shall be a value obtained from an earlier successful call to the fgetpos
on the stream, clears the end-of-file indicator for the stream, and then establishes the new
parse state and position. After a successful fsetpos call, the next operation on an
-[<a name="
#p336" href="p336">page 336</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p336" href="#p336">page 336</a>] (<a href="#Contents">Contents</a>)
update stream may be either input or output.
- Returns
+<b> Returns</b>
4 If successful, the fsetpos function returns zero; on failure, the fsetpos function
returns nonzero and stores an implementation-defined positive value in errno.
<a name="7.21.9.4" href="#7.21.9.4"><b> 7.21.9.4 The ftell function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
long int ftell(FILE *stream);
- Description
+<b> Description</b>
2 The ftell function obtains the current value of the file position indicator for the stream
pointed to by stream. For a binary stream, the value is the number of characters from
the beginning of the file. For a text stream, its file position indicator contains unspecified
stream to its position at the time of the ftell call; the difference between two such
return values is not necessarily a meaningful measure of the number of characters written
or read.
- Returns
+<b> Returns</b>
3 If successful, the ftell function returns the current value of the file position indicator
for the stream. On failure, the ftell function returns -1L and stores an
implementation-defined positive value in errno.
<a name="7.21.9.5" href="#7.21.9.5"><b> 7.21.9.5 The rewind function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
void rewind(FILE *stream);
- Description
+<b> Description</b>
2 The rewind function sets the file position indicator for the stream pointed to by
stream to the beginning of the file. It is equivalent to
(void)fseek(stream, 0L, SEEK_SET)
except that the error indicator for the stream is also cleared.
- Returns
+<b> Returns</b>
3 The rewind function returns no value.
-
-
-
-[<a name="#p337" href="p337">page 337</a>] (<a href="#Contents">Contents</a>)
+[<a name="p337" href="#p337">page 337</a>] (<a href="#Contents">Contents</a>)
<a name="7.21.10" href="#7.21.10"><b> 7.21.10 Error-handling functions</b></a>
<a name="7.21.10.1" href="#7.21.10.1"><b> 7.21.10.1 The clearerr function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
void clearerr(FILE *stream);
- Description
+<b> Description</b>
2 The clearerr function clears the end-of-file and error indicators for the stream pointed
to by stream.
- Returns
+<b> Returns</b>
3 The clearerr function returns no value.
<a name="7.21.10.2" href="#7.21.10.2"><b> 7.21.10.2 The feof function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int feof(FILE *stream);
- Description
+<b> Description</b>
2 The feof function tests the end-of-file indicator for the stream pointed to by stream.
- Returns
+<b> Returns</b>
3 The feof function returns nonzero if and only if the end-of-file indicator is set for
stream.
<a name="7.21.10.3" href="#7.21.10.3"><b> 7.21.10.3 The ferror function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
int ferror(FILE *stream);
- Description
+<b> Description</b>
2 The ferror function tests the error indicator for the stream pointed to by stream.
- Returns
+<b> Returns</b>
3 The ferror function returns nonzero if and only if the error indicator is set for
stream.
-
-
-
-[<a name="#p338" href="p338">page 338</a>] (<a href="#Contents">Contents</a>)
+[<a name="p338" href="#p338">page 338</a>] (<a href="#Contents">Contents</a>)
<a name="7.21.10.4" href="#7.21.10.4"><b> 7.21.10.4 The perror function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
void perror(const char *s);
- Description
+<b> Description</b>
2 The perror function maps the error number in the integer expression errno to an
error message. It writes a sequence of characters to the standard error stream thus: first
(if s is not a null pointer and the character pointed to by s is not the null character), the
string pointed to by s followed by a colon (:) and a space; then an appropriate error
message string followed by a new-line character. The contents of the error message
strings are the same as those returned by the strerror function with argument errno.
- Returns
+<b> Returns</b>
3 The perror function returns no value.
Forward references: the strerror function (<a href="#7.23.6.2">7.23.6.2</a>).
-
-
-
-[<a name="#p339" href="p339">page 339</a>] (<a href="#Contents">Contents</a>)
+[<a name="p339" href="#p339">page 339</a>] (<a href="#Contents">Contents</a>)
<a name="7.22" href="#7.22"><b> 7.22 General utilities <stdlib.h></b></a>
1 The header <a href="#7.22"><stdlib.h></a> declares five types and several functions of general utility, and
- defines several macros.284)
+ defines several macros.<sup><a href="#note284"><b>284)</b></a></sup>
2 The types declared are size_t and wchar_t (both described in <a href="#7.19">7.19</a>),
div_t
which is a structure type that is the type of the value returned by the div function,
-
284) See ''future library directions'' (<a href="#7.30.10">7.30.10</a>).
+
<sup><a name="note284" href="#note284"><b>284)</b></a></sup> See ''future library directions'' (<a href="#7.30.10">7.30.10</a>).
-[<a name="
#p340" href="p340">page 340</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p340" href="#p340">page 340</a>] (<a href="#Contents">Contents</a>)
<a name="7.22.1" href="#7.22.1"><b> 7.22.1 Numeric conversion functions</b></a>
1 The functions atof, atoi, atol, and atoll need not affect the value of the integer
expression errno on an error. If the value of the result cannot be represented, the
behavior is undefined.
<a name="7.22.1.1" href="#7.22.1.1"><b> 7.22.1.1 The atof function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
double atof(const char *nptr);
- Description
+<b> Description</b>
2 The atof function converts the initial portion of the string pointed to by nptr to
double representation. Except for the behavior on error, it is equivalent to
strtod(nptr, (char **)NULL)
- Returns
+<b> Returns</b>
3 The atof function returns the converted value.
Forward references: the strtod, strtof, and strtold functions (<a href="#7.22.1.3">7.22.1.3</a>).
<a name="7.22.1.2" href="#7.22.1.2"><b> 7.22.1.2 The atoi, atol, and atoll functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
int atoi(const char *nptr);
long int atol(const char *nptr);
long long int atoll(const char *nptr);
- Description
+<b> Description</b>
2 The atoi, atol, and atoll functions convert the initial portion of the string pointed
to by nptr to int, long int, and long long int representation, respectively.
Except for the behavior on error, they are equivalent to
atoi: (int)strtol(nptr, (char **)NULL, 10)
atol: strtol(nptr, (char **)NULL, 10)
atoll: strtoll(nptr, (char **)NULL, 10)
- Returns
+<b> Returns</b>
3 The atoi, atol, and atoll functions return the converted value.
Forward references: the strtol, strtoll, strtoul, and strtoull functions
(<a href="#7.22.1.4">7.22.1.4</a>).
-
-
-[<a name="#p341" href="p341">page 341</a>] (<a href="#Contents">Contents</a>)
+[<a name="p341" href="#p341">page 341</a>] (<a href="#Contents">Contents</a>)
<a name="7.22.1.3" href="#7.22.1.3"><b> 7.22.1.3 The strtod, strtof, and strtold functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
double strtod(const char * restrict nptr,
char ** restrict endptr);
char ** restrict endptr);
long double strtold(const char * restrict nptr,
char ** restrict endptr);
- Description
+<b> Description</b>
2 The strtod, strtof, and strtold functions convert the initial portion of the string
pointed to by nptr to double, float, and long double representation,
respectively. First, they decompose the input string into three parts: an initial, possibly
4 If the subject sequence has the expected form for a floating-point number, the sequence of
characters starting with the first digit or the decimal-point character (whichever occurs
first) is interpreted as a floating constant according to the rules of <a href="#6.4.4.2">6.4.4.2</a>, except that the
-[<a name="#p342" href="p342">page 342</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p342" href="#p342">page 342</a>] (<a href="#Contents">Contents</a>)
decimal-point character is used in place of a period, and that if neither an exponent part
nor a decimal-point character appears in a decimal floating point number, or if a binary
exponent part does not appear in a hexadecimal floating point number, an exponent part
of the appropriate type with value zero is assumed to follow the last digit in the string. If
- the subject sequence begins with a minus sign, the sequence is interpreted as negated.285)
+ the subject sequence begins with a minus sign, the sequence is interpreted as negated.<sup><a href="#note285"><b>285)</b></a></sup>
A character sequence INF or INFINITY is interpreted as an infinity, if representable in
the return type, else like a floating constant that is too large for the range of the return
type. A character sequence NAN or NAN(n-char-sequenceopt), is interpreted as a quiet
NaN, if supported in the return type, else like a subject sequence part that does not have
- the expected form; the meaning of the n-char sequences is implementation-defined.286) A
+ the expected form; the meaning of the n-char sequences is implementation-defined.<sup><a href="#note286"><b>286)</b></a></sup> A
pointer to the final string is stored in the object pointed to by endptr, provided that
endptr is not a null pointer.
5 If the subject sequence has the hexadecimal form and FLT_RADIX is a power of 2, the
The result should be one of the (equal or adjacent) values that would be obtained by
correctly rounding L and U according to the current rounding direction, with the extra
- 285) It is unspecified whether a minus-signed sequence is converted to a negative number directly or by
+ <sup><a name="note285" href="#note285"><b>285)</b></a></sup> It is unspecified whether a minus-signed sequence is converted to a negative number directly or by
negating the value resulting from converting the corresponding unsigned sequence (see <a href="#F.5">F.5</a>); the two
methods may yield different results if rounding is toward positive or negative infinity. In either case,
the functions honor the sign of zero if floating-point arithmetic supports signed zeros.
- 286) An implementation may use the n-char sequence to determine extra information to be represented in
+ <sup><a name="note286" href="#note286"><b>286)</b></a></sup> An implementation may use the n-char sequence to determine extra information to be represented in
the NaN's significand.
-[<a name="
#p343" href="p343">page 343</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p343" href="#p343">page 343</a>] (<a href="#Contents">Contents</a>)
stipulation that the error with respect to D should have a correct sign for the current
- rounding direction.287)
- Returns
+ rounding direction.<sup><a href="#note287"><b>287)</b></a></sup>
+<b> Returns</b>
10 The functions return the converted value, if any. If no conversion could be performed,
zero is returned. If the correct value overflows and default rounding is in effect (<a href="#7.12.1">7.12.1</a>),
plus or minus HUGE_VAL, HUGE_VALF, or HUGE_VALL is returned (according to the
no greater than the smallest normalized positive number in the return type; whether
errno acquires the value ERANGE is implementation-defined.
<a name="7.22.1.4" href="#7.22.1.4"><b> 7.22.1.4 The strtol, strtoll, strtoul, and strtoull functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
long int strtol(
const char * restrict nptr,
const char * restrict nptr,
char ** restrict endptr,
int base);
- Description
+<b> Description</b>
2 The strtol, strtoll, strtoul, and strtoull functions convert the initial
portion of the string pointed to by nptr to long int, long long int, unsigned
long int, and unsigned long long int representation, respectively. First,
white-space characters (as specified by the isspace function), a subject sequence
-
287) DECIMAL_DIG, defined in <a href="#7.7"><float.h></a>, should be sufficiently large that L and U will usually round
+
<sup><a name="note287" href="#note287"><b>287)</b></a></sup> DECIMAL_DIG, defined in <a href="#7.7"><float.h></a>, should be sufficiently large that L and U will usually round
to the same internal floating value, but if not will round to adjacent values.
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+[<a name="
p344" href="#p344">page 344</a>] (<a href="#Contents">Contents</a>)
resembling an integer represented in some radix determined by the value of base, and a
final string of one or more unrecognized characters, including the terminating null
7 If the subject sequence is empty or does not have the expected form, no conversion is
performed; the value of nptr is stored in the object pointed to by endptr, provided
that endptr is not a null pointer.
- Returns
+<b> Returns</b>
8 The strtol, strtoll, strtoul, and strtoull functions return the converted
value, if any. If no conversion could be performed, zero is returned. If the correct value
is outside the range of representable values, LONG_MIN, LONG_MAX, LLONG_MIN,
LLONG_MAX, ULONG_MAX, or ULLONG_MAX is returned (according to the return type
and sign of the value, if any), and the value of the macro ERANGE is stored in errno.
-
-
-
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+[<a name="p345" href="#p345">page 345</a>] (<a href="#Contents">Contents</a>)
<a name="7.22.2" href="#7.22.2"><b> 7.22.2 Pseudo-random sequence generation functions</b></a>
<a name="7.22.2.1" href="#7.22.2.1"><b> 7.22.2.1 The rand function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
int rand(void);
- Description
+<b> Description</b>
2 The rand function computes a sequence of pseudo-random integers in the range 0 to
- RAND_MAX.288)
+ RAND_MAX.<sup><a href="#note288"><b>288)</b></a></sup>
3 The rand function is not required to avoid data races. The implementation shall behave
as if no library function calls the rand function.
- Returns
+<b> Returns</b>
4 The rand function returns a pseudo-random integer.
Environmental limits
5 The value of the RAND_MAX macro shall be at least 32767.
<a name="7.22.2.2" href="#7.22.2.2"><b> 7.22.2.2 The srand function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
void srand(unsigned int seed);
- Description
+<b> Description</b>
2 The srand function uses the argument as a seed for a new sequence of pseudo-random
numbers to be returned by subsequent calls to rand. If srand is then called with the
same seed value, the sequence of pseudo-random numbers shall be repeated. If rand is
called before any calls to srand have been made, the same sequence shall be generated
as when srand is first called with a seed value of 1.
3 The implementation shall behave as if no library function calls the srand function.
- Returns
+<b> Returns</b>
4 The srand function returns no value.
- 288) There are no guarantees as to the quality of the random sequence produced and some implementations
+ <sup><a name="note288" href="#note288"><b>288)</b></a></sup> There are no guarantees as to the quality of the random sequence produced and some implementations
are known to produce sequences with distressingly non-random low-order bits. Applications with
particular requirements should use a generator that is known to be sufficient for their needs.
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+[<a name="
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5 EXAMPLE The following functions define a portable implementation of rand and srand.
static unsigned long int next = 1;
is returned, or the behavior is as if the size were some nonzero value, except that the
returned pointer shall not be used to access an object.
<a name="7.22.3.1" href="#7.22.3.1"><b> 7.22.3.1 The aligned_alloc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
void *aligned_alloc(size_t alignment, size_t size);
- Description
+<b> Description</b>
2 The aligned_alloc function allocates space for an object whose alignment is
specified by alignment, whose size is specified by size, and whose value is
indeterminate. The value of alignment shall be a valid alignment supported by the
implementation and the value of size shall be an integral multiple of alignment.
- Returns
+<b> Returns</b>
3 The aligned_alloc function returns either a null pointer or a pointer to the allocated
space.
-
-
-
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+[<a name="p347" href="#p347">page 347</a>] (<a href="#Contents">Contents</a>)
<a name="7.22.3.2" href="#7.22.3.2"><b> 7.22.3.2 The calloc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
void *calloc(size_t nmemb, size_t size);
- Description
+<b> Description</b>
2 The calloc function allocates space for an array of nmemb objects, each of whose size
- is size. The space is initialized to all bits zero.289)
- Returns
+ is size. The space is initialized to all bits zero.<sup><a href="#note289"><b>289)</b></a></sup>
+<b> Returns</b>
3 The calloc function returns either a null pointer or a pointer to the allocated space.
<a name="7.22.3.3" href="#7.22.3.3"><b> 7.22.3.3 The free function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
void free(void *ptr);
- Description
+<b> Description</b>
2 The free function causes the space pointed to by ptr to be deallocated, that is, made
available for further allocation. If ptr is a null pointer, no action occurs. Otherwise, if
the argument does not match a pointer earlier returned by a memory management
function, or if the space has been deallocated by a call to free or realloc, the
behavior is undefined.
- Returns
+<b> Returns</b>
3 The free function returns no value.
<a name="7.22.3.4" href="#7.22.3.4"><b> 7.22.3.4 The malloc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
void *malloc(size_t size);
- Description
+<b> Description</b>
2 The malloc function allocates space for an object whose size is specified by size and
whose value is indeterminate.
- 289) Note that this need not be the same as the representation of floating-point zero or a null pointer
+ <sup><a name="note289" href="#note289"><b>289)</b></a></sup> Note that this need not be the same as the representation of floating-point zero or a null pointer
constant.
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#p348" href="p348">page 348</a>] (<a href="#Contents">Contents</a>)
+[<a name="
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- Returns
+<b> Returns</b>
3 The malloc function returns either a null pointer or a pointer to the allocated space.
<a name="7.22.3.5" href="#7.22.3.5"><b> 7.22.3.5 The realloc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
void *realloc(void *ptr, size_t size);
- Description
+<b> Description</b>
2 The realloc function deallocates the old object pointed to by ptr and returns a
pointer to a new object that has the size specified by size. The contents of the new
object shall be the same as that of the old object prior to deallocation, up to the lesser of
management function, or if the space has been deallocated by a call to the free or
realloc function, the behavior is undefined. If memory for the new object cannot be
allocated, the old object is not deallocated and its value is unchanged.
- Returns
+<b> Returns</b>
4 The realloc function returns a pointer to the new object (which may have the same
value as a pointer to the old object), or a null pointer if the new object could not be
allocated.
<a name="7.22.4" href="#7.22.4"><b> 7.22.4 Communication with the environment</b></a>
<a name="7.22.4.1" href="#7.22.4.1"><b> 7.22.4.1 The abort function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
_Noreturn void abort(void);
- Description
+<b> Description</b>
2 The abort function causes abnormal program termination to occur, unless the signal
SIGABRT is being caught and the signal handler does not return. Whether open streams
with unwritten buffered data are flushed, open streams are closed, or temporary files are
unsuccessful termination is returned to the host environment by means of the function
call raise(SIGABRT).
+[<a name="p349" href="#p349">page 349</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p349" href="p349">page 349</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The abort function does not return to its caller.
<a name="7.22.4.2" href="#7.22.4.2"><b> 7.22.4.2 The atexit function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
int atexit(void (*func)(void));
- Description
+<b> Description</b>
2 The atexit function registers the function pointed to by func, to be called without
- arguments at normal program termination.290)
+ arguments at normal program termination.<sup><a href="#note290"><b>290)</b></a></sup>
Environmental limits
3 The implementation shall support the registration of at least 32 functions.
- Returns
+<b> Returns</b>
4 The atexit function returns zero if the registration succeeds, nonzero if it fails.
Forward references: the at_quick_exit function (<a href="#7.22.4.3">7.22.4.3</a>), the exit function
(<a href="#7.22.4.4">7.22.4.4</a>).
<a name="7.22.4.3" href="#7.22.4.3"><b> 7.22.4.3 The at_quick_exit function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
int at_quick_exit(void (*func)(void));
- Description
+<b> Description</b>
2 The at_quick_exit function registers the function pointed to by func, to be called
- without arguments should quick_exit be called.291)
+ without arguments should quick_exit be called.<sup><a href="#note291"><b>291)</b></a></sup>
Environmental limits
3 The implementation shall support the registration of at least 32 functions.
- Returns
+<b> Returns</b>
4 The at_quick_exit function returns zero if the registration succeeds, nonzero if it
fails.
Forward references: the quick_exit function (<a href="#7.22.4.7">7.22.4.7</a>).
- 290) The atexit function registrations are distinct from the at_quick_exit registrations, so
+ <sup><a name="note290" href="#note290"><b>290)</b></a></sup> The atexit function registrations are distinct from the at_quick_exit registrations, so
applications may need to call both registration functions with the same argument.
- 291) The at_quick_exit function registrations are distinct from the atexit registrations, so
+ <sup><a name="note291" href="#note291"><b>291)</b></a></sup> The at_quick_exit function registrations are distinct from the atexit registrations, so
applications may need to call both registration functions with the same argument.
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+[<a name="
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<a name="7.22.4.4" href="#7.22.4.4"><b> 7.22.4.4 The exit function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
_Noreturn void exit(int status);
- Description
+<b> Description</b>
2 The exit function causes normal program termination to occur. No functions registered
by the at_quick_exit function are called. If a program calls the exit function
more than once, or calls the quick_exit function in addition to the exit function, the
behavior is undefined.
3 First, all functions registered by the atexit function are called, in the reverse order of
- their registration,292) except that a function is called after any previously registered
+ their registration,<sup><a href="#note292"><b>292)</b></a></sup> except that a function is called after any previously registered
functions that had already been called at the time it was registered. If, during the call to
any such function, a call to the longjmp function is made that would terminate the call
to the registered function, the behavior is undefined.
returned. If the value of status is EXIT_FAILURE, an implementation-defined form
of the status unsuccessful termination is returned. Otherwise the status returned is
implementation-defined.
- Returns
+<b> Returns</b>
6 The exit function cannot return to its caller.
<a name="7.22.4.5" href="#7.22.4.5"><b> 7.22.4.5 The _Exit function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
_Noreturn void _Exit(int status);
- Description
+<b> Description</b>
2 The _Exit function causes normal program termination to occur and control to be
returned to the host environment. No functions registered by the atexit function, the
at_quick_exit function, or signal handlers registered by the signal function are
called. The status returned to the host environment is determined in the same way as for
- 292) Each function is called as many times as it was registered, and in the correct order with respect to
+ <sup><a name="note292" href="#note292"><b>292)</b></a></sup> Each function is called as many times as it was registered, and in the correct order with respect to
other registered functions.
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the exit function (<a href="#7.22.4.4">7.22.4.4</a>). Whether open streams with unwritten buffered data are
flushed, open streams are closed, or temporary files are removed is implementation-
defined.
- Returns
+<b> Returns</b>
3 The _Exit function cannot return to its caller.
<a name="7.22.4.6" href="#7.22.4.6"><b> 7.22.4.6 The getenv function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
char *getenv(const char *name);
- Description
+<b> Description</b>
2 The getenv function searches an environment list, provided by the host environment,
for a string that matches the string pointed to by name. The set of environment names
and the method for altering the environment list are implementation-defined. The
getenv function need not avoid data races with other threads of execution that modify
- the environment list.293)
+ the environment list.<sup><a href="#note293"><b>293)</b></a></sup>
3 The implementation shall behave as if no library function calls the getenv function.
- Returns
+<b> Returns</b>
4 The getenv function returns a pointer to a string associated with the matched list
member. The string pointed to shall not be modified by the program, but may be
overwritten by a subsequent call to the getenv function. If the specified name cannot
be found, a null pointer is returned.
<a name="7.22.4.7" href="#7.22.4.7"><b> 7.22.4.7 The quick_exit function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
_Noreturn void quick_exit(int status);
- Description
+<b> Description</b>
2 The quick_exit function causes normal program termination to occur. No functions
registered by the atexit function or signal handlers registered by the signal function
are called. If a program calls the quick_exit function more than once, or calls the
exit function in addition to the quick_exit function, the behavior is undefined.
3 The quick_exit function first calls all functions registered by the at_quick_exit
- function, in the reverse order of their registration,294) except that a function is called after
+ function, in the reverse order of their registration,<sup><a href="#note294"><b>294)</b></a></sup> except that a function is called after
- 293) Many implementations provide non-standard functions that modify the environment list.
+ <sup><a name="note293" href="#note293"><b>293)</b></a></sup> Many implementations provide non-standard functions that modify the environment list.
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any previously registered functions that had already been called at the time it was
registered. If, during the call to any such function, a call to the longjmp function is
made that would terminate the call to the registered function, the behavior is undefined.
4 Then control is returned to the host environment by means of the function call
_Exit(status).
- Returns
+<b> Returns</b>
5 The quick_exit function cannot return to its caller.
<a name="7.22.4.8" href="#7.22.4.8"><b> 7.22.4.8 The system function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
int system(const char *string);
- Description
+<b> Description</b>
2 If string is a null pointer, the system function determines whether the host
environment has a command processor. If string is not a null pointer, the system
function passes the string pointed to by string to that command processor to be
executed in a manner which the implementation shall document; this might then cause the
program calling system to behave in a non-conforming manner or to terminate.
- Returns
+<b> Returns</b>
3 If the argument is a null pointer, the system function returns nonzero only if a
command processor is available. If the argument is not a null pointer, and the system
function does return, it returns an implementation-defined value.
in <a href="#7.1.4">7.1.4</a>.
2 The implementation shall ensure that the second argument of the comparison function
(when called from bsearch), or both arguments (when called from qsort), are
- pointers to elements of the array.295) The first argument when called from bsearch
+ pointers to elements of the array.<sup><a href="#note295"><b>295)</b></a></sup> The first argument when called from bsearch
shall equal key.
- 294) Each function is called as many times as it was registered, and in the correct order with respect to
+ <sup><a name="note294" href="#note294"><b>294)</b></a></sup> Each function is called as many times as it was registered, and in the correct order with respect to
other registered functions.
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#p353" href="p353">page 353</a>] (<a href="#Contents">Contents</a>)
+[<a name="
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3 The comparison function shall not alter the contents of the array. The implementation
may reorder elements of the array between calls to the comparison function, but shall not
comparison function, and also between any call to the comparison function and any
movement of the objects passed as arguments to that call.
<a name="7.22.5.1" href="#7.22.5.1"><b> 7.22.5.1 The bsearch function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
void *bsearch(const void *key, const void *base,
size_t nmemb, size_t size,
int (*compar)(const void *, const void *));
- Description
+<b> Description</b>
2 The bsearch function searches an array of nmemb objects, the initial element of which
is pointed to by base, for an element that matches the object pointed to by key. The
size of each element of the array is specified by size.
integer less than, equal to, or greater than zero if the key object is considered,
respectively, to be less than, to match, or to be greater than the array element. The array
shall consist of: all the elements that compare less than, all the elements that compare
- equal to, and all the elements that compare greater than the key object, in that order.296)
- Returns
+ equal to, and all the elements that compare greater than the key object, in that order.<sup><a href="#note296"><b>296)</b></a></sup>
+<b> Returns</b>
4 The bsearch function returns a pointer to a matching element of the array, or a null
pointer if no match is found. If two elements compare as equal, which element is
- 295) That is, if the value passed is p, then the following expressions are always nonzero:
+ <sup><a name="note295" href="#note295"><b>295)</b></a></sup> That is, if the value passed is p, then the following expressions are always nonzero:
((char *)p - (char *)base) % size == 0
(char *)p >= (char *)base
(char *)p < (char *)base + nmemb * size
- 296) In practice, the entire array is sorted according to the comparison function.
+ <sup><a name="note296" href="#note296"><b>296)</b></a></sup> In practice, the entire array is sorted according to the comparison function.
-[<a name="
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matched is unspecified.
<a name="7.22.5.2" href="#7.22.5.2"><b> 7.22.5.2 The qsort function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
void qsort(void *base, size_t nmemb, size_t size,
int (*compar)(const void *, const void *));
- Description
+<b> Description</b>
2 The qsort function sorts an array of nmemb objects, the initial element of which is
pointed to by base. The size of each object is specified by size.
3 The contents of the array are sorted into ascending order according to a comparison
greater than zero if the first argument is considered to be respectively less than, equal to,
or greater than the second.
4 If two elements compare as equal, their order in the resulting sorted array is unspecified.
- Returns
+<b> Returns</b>
5 The qsort function returns no value.
<a name="7.22.6" href="#7.22.6"><b> 7.22.6 Integer arithmetic functions</b></a>
<a name="7.22.6.1" href="#7.22.6.1"><b> 7.22.6.1 The abs, labs and llabs functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
int abs(int j);
long int labs(long int j);
long long int llabs(long long int j);
- Description
+<b> Description</b>
2 The abs, labs, and llabs functions compute the absolute value of an integer j. If the
- result cannot be represented, the behavior is undefined.297)
- Returns
+ result cannot be represented, the behavior is undefined.<sup><a href="#note297"><b>297)</b></a></sup>
+<b> Returns</b>
3 The abs, labs, and llabs, functions return the absolute value.
- 297) The absolute value of the most negative number cannot be represented in two's complement.
+ <sup><a name="note297" href="#note297"><b>297)</b></a></sup> The absolute value of the most negative number cannot be represented in two's complement.
-[<a name="
#p355" href="p355">page 355</a>] (<a href="#Contents">Contents</a>)
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<a name="7.22.6.2" href="#7.22.6.2"><b> 7.22.6.2 The div, ldiv, and lldiv functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
div_t div(int numer, int denom);
ldiv_t ldiv(long int numer, long int denom);
lldiv_t lldiv(long long int numer, long long int denom);
- Description
+<b> Description</b>
2 The div, ldiv, and lldiv, functions compute numer / denom and numer %
denom in a single operation.
- Returns
+<b> Returns</b>
3 The div, ldiv, and lldiv functions return a structure of type div_t, ldiv_t, and
lldiv_t, respectively, comprising both the quotient and the remainder. The structures
shall contain (in either order) the members quot (the quotient) and rem (the remainder),
which its character pointer argument, s, is a null pointer. Subsequent calls with s as
other than a null pointer cause the internal conversion state of the function to be altered as
necessary. A call with s as a null pointer causes these functions to return a nonzero value
- if encodings have state dependency, and zero otherwise.298) Changing the LC_CTYPE
+ if encodings have state dependency, and zero otherwise.<sup><a href="#note298"><b>298)</b></a></sup> Changing the LC_CTYPE
category causes the conversion state of these functions to be indeterminate.
<a name="7.22.7.1" href="#7.22.7.1"><b> 7.22.7.1 The mblen function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
int mblen(const char *s, size_t n);
- Description
+<b> Description</b>
2 If s is not a null pointer, the mblen function determines the number of bytes contained
in the multibyte character pointed to by s. Except that the conversion state of the
mbtowc function is not affected, it is equivalent to
- 298) If the locale employs special bytes to change the shift state, these bytes do not produce separate wide
+ <sup><a name="note298" href="#note298"><b>298)</b></a></sup> If the locale employs special bytes to change the shift state, these bytes do not produce separate wide
character codes, but are grouped with an adjacent multibyte character.
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mbtowc((wchar_t *)0, (const char *)0, 0);
mbtowc((wchar_t *)0, s, n);
3 The implementation shall behave as if no library function calls the mblen function.
- Returns
+<b> Returns</b>
4 If s is a null pointer, the mblen function returns a nonzero or zero value, if multibyte
character encodings, respectively, do or do not have state-dependent encodings. If s is
not a null pointer, the mblen function either returns 0 (if s points to the null character),
multibyte character).
Forward references: the mbtowc function (<a href="#7.22.7.2">7.22.7.2</a>).
<a name="7.22.7.2" href="#7.22.7.2"><b> 7.22.7.2 The mbtowc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
int mbtowc(wchar_t * restrict pwc,
const char * restrict s,
size_t n);
- Description
+<b> Description</b>
2 If s is not a null pointer, the mbtowc function inspects at most n bytes beginning with
the byte pointed to by s to determine the number of bytes needed to complete the next
multibyte character (including any shift sequences). If the function determines that the
the object pointed to by pwc. If the corresponding wide character is the null wide
character, the function is left in the initial conversion state.
3 The implementation shall behave as if no library function calls the mbtowc function.
- Returns
+<b> Returns</b>
4 If s is a null pointer, the mbtowc function returns a nonzero or zero value, if multibyte
character encodings, respectively, do or do not have state-dependent encodings. If s is
not a null pointer, the mbtowc function either returns 0 (if s points to the null character),
5 In no case will the value returned be greater than n or the value of the MB_CUR_MAX
macro.
-
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+[<a name="p357" href="#p357">page 357</a>] (<a href="#Contents">Contents</a>)
<a name="7.22.7.3" href="#7.22.7.3"><b> 7.22.7.3 The wctomb function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
int wctomb(char *s, wchar_t wc);
- Description
+<b> Description</b>
2 The wctomb function determines the number of bytes needed to represent the multibyte
character corresponding to the wide character given by wc (including any shift
sequences), and stores the multibyte character representation in the array whose first
sequence needed to restore the initial shift state, and the function is left in the initial
conversion state.
3 The implementation shall behave as if no library function calls the wctomb function.
- Returns
+<b> Returns</b>
4 If s is a null pointer, the wctomb function returns a nonzero or zero value, if multibyte
character encodings, respectively, do or do not have state-dependent encodings. If s is
not a null pointer, the wctomb function returns -1 if the value of wc does not correspond
1 The behavior of the multibyte string functions is affected by the LC_CTYPE category of
the current locale.
<a name="7.22.8.1" href="#7.22.8.1"><b> 7.22.8.1 The mbstowcs function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
size_t mbstowcs(wchar_t * restrict pwcs,
const char * restrict s,
size_t n);
- Description
+<b> Description</b>
2 The mbstowcs function converts a sequence of multibyte characters that begins in the
initial shift state from the array pointed to by s into a sequence of corresponding wide
characters and stores not more than n wide characters into the array pointed to by pwcs.
No multibyte characters that follow a null character (which is converted into a null wide
character) will be examined or converted. Each multibyte character is converted as if by
a call to the mbtowc function, except that the conversion state of the mbtowc function is
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+
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not affected.
3 No more than n elements will be modified in the array pointed to by pwcs. If copying
takes place between objects that overlap, the behavior is undefined.
- Returns
+<b> Returns</b>
4 If an invalid multibyte character is encountered, the mbstowcs function returns
(size_t)(-1). Otherwise, the mbstowcs function returns the number of array
- elements modified, not including a terminating null wide character, if any.299)
+ elements modified, not including a terminating null wide character, if any.<sup><a href="#note299"><b>299)</b></a></sup>
<a name="7.22.8.2" href="#7.22.8.2"><b> 7.22.8.2 The wcstombs function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
size_t wcstombs(char * restrict s,
const wchar_t * restrict pwcs,
size_t n);
- Description
+<b> Description</b>
2 The wcstombs function converts a sequence of wide characters from the array pointed
to by pwcs into a sequence of corresponding multibyte characters that begins in the
initial shift state, and stores these multibyte characters into the array pointed to by s,
function, except that the conversion state of the wctomb function is not affected.
3 No more than n bytes will be modified in the array pointed to by s. If copying takes place
between objects that overlap, the behavior is undefined.
- Returns
+<b> Returns</b>
4 If a wide character is encountered that does not correspond to a valid multibyte character,
the wcstombs function returns (size_t)(-1). Otherwise, the wcstombs function
returns the number of bytes modified, not including a terminating null character, if
- 299) The array will not be null-terminated if the value returned is n.
+ <sup><a name="note299" href="#note299"><b>299)</b></a></sup> The array will not be null-terminated if the value returned is n.
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+[<a name="
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<a name="7.23" href="#7.23"><b> 7.23 String handling <string.h></b></a>
<a name="7.23.1" href="#7.23.1"><b> 7.23.1 String function conventions</b></a>
1 The header <a href="#7.23"><string.h></a> declares one type and several functions, and defines one
macro useful for manipulating arrays of character type and other objects treated as arrays
- of character type.300) The type is size_t and the macro is NULL (both described in
+ of character type.<sup><a href="#note300"><b>300)</b></a></sup> The type is size_t and the macro is NULL (both described in
<a name="7.19)" href="#7.19)"><b> 7.19). Various methods are used for determining the lengths of the arrays, but in all cases</b></a>
a char * or void * argument points to the initial (lowest addressed) character of the
array. If an array is accessed beyond the end of an object, the behavior is undefined.
different value).
<a name="7.23.2" href="#7.23.2"><b> 7.23.2 Copying functions</b></a>
<a name="7.23.2.1" href="#7.23.2.1"><b> 7.23.2.1 The memcpy function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
void *memcpy(void * restrict s1,
const void * restrict s2,
size_t n);
- Description
+<b> Description</b>
2 The memcpy function copies n characters from the object pointed to by s2 into the
object pointed to by s1. If copying takes place between objects that overlap, the behavior
is undefined.
- Returns
+<b> Returns</b>
3 The memcpy function returns the value of s1.
-
300) See ''future library directions'' (<a href="#7.30.11">7.30.11</a>).
+
<sup><a name="note300" href="#note300"><b>300)</b></a></sup> See ''future library directions'' (<a href="#7.30.11">7.30.11</a>).
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<a name="7.23.2.2" href="#7.23.2.2"><b> 7.23.2.2 The memmove function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
void *memmove(void *s1, const void *s2, size_t n);
- Description
+<b> Description</b>
2 The memmove function copies n characters from the object pointed to by s2 into the
object pointed to by s1. Copying takes place as if the n characters from the object
pointed to by s2 are first copied into a temporary array of n characters that does not
overlap the objects pointed to by s1 and s2, and then the n characters from the
temporary array are copied into the object pointed to by s1.
- Returns
+<b> Returns</b>
3 The memmove function returns the value of s1.
<a name="7.23.2.3" href="#7.23.2.3"><b> 7.23.2.3 The strcpy function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
char *strcpy(char * restrict s1,
const char * restrict s2);
- Description
+<b> Description</b>
2 The strcpy function copies the string pointed to by s2 (including the terminating null
character) into the array pointed to by s1. If copying takes place between objects that
overlap, the behavior is undefined.
- Returns
+<b> Returns</b>
3 The strcpy function returns the value of s1.
<a name="7.23.2.4" href="#7.23.2.4"><b> 7.23.2.4 The strncpy function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
char *strncpy(char * restrict s1,
const char * restrict s2,
size_t n);
- Description
+<b> Description</b>
2 The strncpy function copies not more than n characters (characters that follow a null
character are not copied) from the array pointed to by s2 to the array pointed to by
+[<a name="p361" href="#p361">page 361</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p361" href="p361">page 361</a>] (<a href="#Contents">Contents</a>)
-
- s1.301) If copying takes place between objects that overlap, the behavior is undefined.
+ s1.<sup><a href="#note301"><b>301)</b></a></sup> If copying takes place between objects that overlap, the behavior is undefined.
3 If the array pointed to by s2 is a string that is shorter than n characters, null characters
are appended to the copy in the array pointed to by s1, until n characters in all have been
written.
- Returns
+<b> Returns</b>
4 The strncpy function returns the value of s1.
<a name="7.23.3" href="#7.23.3"><b> 7.23.3 Concatenation functions</b></a>
<a name="7.23.3.1" href="#7.23.3.1"><b> 7.23.3.1 The strcat function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
char *strcat(char * restrict s1,
const char * restrict s2);
- Description
+<b> Description</b>
2 The strcat function appends a copy of the string pointed to by s2 (including the
terminating null character) to the end of the string pointed to by s1. The initial character
of s2 overwrites the null character at the end of s1. If copying takes place between
objects that overlap, the behavior is undefined.
- Returns
+<b> Returns</b>
3 The strcat function returns the value of s1.
<a name="7.23.3.2" href="#7.23.3.2"><b> 7.23.3.2 The strncat function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
char *strncat(char * restrict s1,
const char * restrict s2,
size_t n);
- Description
+<b> Description</b>
2 The strncat function appends not more than n characters (a null character and
characters that follow it are not appended) from the array pointed to by s2 to the end of
the string pointed to by s1. The initial character of s2 overwrites the null character at the
- end of s1. A terminating null character is always appended to the result.302) If copying
+ end of s1. A terminating null character is always appended to the result.<sup><a href="#note302"><b>302)</b></a></sup> If copying
- 301) Thus, if there is no null character in the first n characters of the array pointed to by s2, the result will
+ <sup><a name="note301" href="#note301"><b>301)</b></a></sup> Thus, if there is no null character in the first n characters of the array pointed to by s2, the result will
not be null-terminated.
- 302) Thus, the maximum number of characters that can end up in the array pointed to by s1 is
+ <sup><a name="note302" href="#note302"><b>302)</b></a></sup> Thus, the maximum number of characters that can end up in the array pointed to by s1 is
strlen(s1)+n+1.
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+[<a name="
p362" href="#p362">page 362</a>] (<a href="#Contents">Contents</a>)
takes place between objects that overlap, the behavior is undefined.
- Returns
+<b> Returns</b>
3 The strncat function returns the value of s1.
Forward references: the strlen function (<a href="#7.23.6.3">7.23.6.3</a>).
<a name="7.23.4" href="#7.23.4"><b> 7.23.4 Comparison functions</b></a>
pair of characters (both interpreted as unsigned char) that differ in the objects being
compared.
<a name="7.23.4.1" href="#7.23.4.1"><b> 7.23.4.1 The memcmp function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
int memcmp(const void *s1, const void *s2, size_t n);
- Description
+<b> Description</b>
2 The memcmp function compares the first n characters of the object pointed to by s1 to
- the first n characters of the object pointed to by s2.303)
- Returns
+ the first n characters of the object pointed to by s2.<sup><a href="#note303"><b>303)</b></a></sup>
+<b> Returns</b>
3 The memcmp function returns an integer greater than, equal to, or less than zero,
accordingly as the object pointed to by s1 is greater than, equal to, or less than the object
pointed to by s2.
<a name="7.23.4.2" href="#7.23.4.2"><b> 7.23.4.2 The strcmp function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
int strcmp(const char *s1, const char *s2);
- Description
+<b> Description</b>
2 The strcmp function compares the string pointed to by s1 to the string pointed to by
s2.
- Returns
+<b> Returns</b>
3 The strcmp function returns an integer greater than, equal to, or less than zero,
accordingly as the string pointed to by s1 is greater than, equal to, or less than the string
- 303) The contents of ''holes'' used as padding for purposes of alignment within structure objects are
+ <sup><a name="note303" href="#note303"><b>303)</b></a></sup> The contents of ''holes'' used as padding for purposes of alignment within structure objects are
indeterminate. Strings shorter than their allocated space and unions may also cause problems in
comparison.
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pointed to by s2.
<a name="7.23.4.3" href="#7.23.4.3"><b> 7.23.4.3 The strcoll function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
int strcoll(const char *s1, const char *s2);
- Description
+<b> Description</b>
2 The strcoll function compares the string pointed to by s1 to the string pointed to by
s2, both interpreted as appropriate to the LC_COLLATE category of the current locale.
- Returns
+<b> Returns</b>
3 The strcoll function returns an integer greater than, equal to, or less than zero,
accordingly as the string pointed to by s1 is greater than, equal to, or less than the string
pointed to by s2 when both are interpreted as appropriate to the current locale.
<a name="7.23.4.4" href="#7.23.4.4"><b> 7.23.4.4 The strncmp function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
int strncmp(const char *s1, const char *s2, size_t n);
- Description
+<b> Description</b>
2 The strncmp function compares not more than n characters (characters that follow a
null character are not compared) from the array pointed to by s1 to the array pointed to
by s2.
- Returns
+<b> Returns</b>
3 The strncmp function returns an integer greater than, equal to, or less than zero,
accordingly as the possibly null-terminated array pointed to by s1 is greater than, equal
to, or less than the possibly null-terminated array pointed to by s2.
<a name="7.23.4.5" href="#7.23.4.5"><b> 7.23.4.5 The strxfrm function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
size_t strxfrm(char * restrict s1,
const char * restrict s2,
size_t n);
- Description
+<b> Description</b>
2 The strxfrm function transforms the string pointed to by s2 and places the resulting
string into the array pointed to by s1. The transformation is such that if the strcmp
function is applied to two transformed strings, it returns a value greater than, equal to, or
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less than zero, corresponding to the result of the strcoll function applied to the same
two original strings. No more than n characters are placed into the resulting array
pointed to by s1, including the terminating null character. If n is zero, s1 is permitted to
be a null pointer. If copying takes place between objects that overlap, the behavior is
undefined.
- Returns
+<b> Returns</b>
3 The strxfrm function returns the length of the transformed string (not including the
terminating null character). If the value returned is n or more, the contents of the array
pointed to by s1 are indeterminate.
<a name="7.23.5" href="#7.23.5"><b> 7.23.5 Search functions</b></a>
<a name="7.23.5.1" href="#7.23.5.1"><b> 7.23.5.1 The memchr function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
void *memchr(const void *s, int c, size_t n);
- Description
+<b> Description</b>
2 The memchr function locates the first occurrence of c (converted to an unsigned
char) in the initial n characters (each interpreted as unsigned char) of the object
pointed to by s. The implementation shall behave as if it reads the characters sequentially
and stops as soon as a matching character is found.
- Returns
+<b> Returns</b>
3 The memchr function returns a pointer to the located character, or a null pointer if the
character does not occur in the object.
<a name="7.23.5.2" href="#7.23.5.2"><b> 7.23.5.2 The strchr function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
char *strchr(const char *s, int c);
- Description
+<b> Description</b>
2 The strchr function locates the first occurrence of c (converted to a char) in the
string pointed to by s. The terminating null character is considered to be part of the
string.
+[<a name="p365" href="#p365">page 365</a>] (<a href="#Contents">Contents</a>)
-
-[<a name="#p365" href="p365">page 365</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The strchr function returns a pointer to the located character, or a null pointer if the
character does not occur in the string.
<a name="7.23.5.3" href="#7.23.5.3"><b> 7.23.5.3 The strcspn function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
size_t strcspn(const char *s1, const char *s2);
- Description
+<b> Description</b>
2 The strcspn function computes the length of the maximum initial segment of the string
pointed to by s1 which consists entirely of characters not from the string pointed to by
s2.
- Returns
+<b> Returns</b>
3 The strcspn function returns the length of the segment.
<a name="7.23.5.4" href="#7.23.5.4"><b> 7.23.5.4 The strpbrk function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
char *strpbrk(const char *s1, const char *s2);
- Description
+<b> Description</b>
2 The strpbrk function locates the first occurrence in the string pointed to by s1 of any
character from the string pointed to by s2.
- Returns
+<b> Returns</b>
3 The strpbrk function returns a pointer to the character, or a null pointer if no character
from s2 occurs in s1.
<a name="7.23.5.5" href="#7.23.5.5"><b> 7.23.5.5 The strrchr function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
char *strrchr(const char *s, int c);
- Description
+<b> Description</b>
2 The strrchr function locates the last occurrence of c (converted to a char) in the
string pointed to by s. The terminating null character is considered to be part of the
string.
+[<a name="p366" href="#p366">page 366</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p366" href="p366">page 366</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The strrchr function returns a pointer to the character, or a null pointer if c does not
occur in the string.
<a name="7.23.5.6" href="#7.23.5.6"><b> 7.23.5.6 The strspn function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
size_t strspn(const char *s1, const char *s2);
- Description
+<b> Description</b>
2 The strspn function computes the length of the maximum initial segment of the string
pointed to by s1 which consists entirely of characters from the string pointed to by s2.
- Returns
+<b> Returns</b>
3 The strspn function returns the length of the segment.
<a name="7.23.5.7" href="#7.23.5.7"><b> 7.23.5.7 The strstr function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
char *strstr(const char *s1, const char *s2);
- Description
+<b> Description</b>
2 The strstr function locates the first occurrence in the string pointed to by s1 of the
sequence of characters (excluding the terminating null character) in the string pointed to
by s2.
- Returns
+<b> Returns</b>
3 The strstr function returns a pointer to the located string, or a null pointer if the string
is not found. If s2 points to a string with zero length, the function returns s1.
<a name="7.23.5.8" href="#7.23.5.8"><b> 7.23.5.8 The strtok function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
char *strtok(char * restrict s1,
const char * restrict s2);
- Description
+<b> Description</b>
2 A sequence of calls to the strtok function breaks the string pointed to by s1 into a
sequence of tokens, each of which is delimited by a character from the string pointed to
by s2. The first call in the sequence has a non-null first argument; subsequent calls in the
sequence have a null first argument. The separator string pointed to by s2 may be
different from call to call.
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+
+[<a name="p367" href="#p367">page 367</a>] (<a href="#Contents">Contents</a>)
3 The first call in the sequence searches the string pointed to by s1 for the first character
that is not contained in the current separator string pointed to by s2. If no such character
searching from the saved pointer and behaves as described above.
6 The strtok function is not required to avoid data races. The implementation shall
behave as if no library function calls the strtok function.
- Returns
+<b> Returns</b>
7 The strtok function returns a pointer to the first character of a token, or a null pointer
if there is no token.
8 EXAMPLE
<a name="7.23.6" href="#7.23.6"><b> 7.23.6 Miscellaneous functions</b></a>
<a name="7.23.6.1" href="#7.23.6.1"><b> 7.23.6.1 The memset function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
void *memset(void *s, int c, size_t n);
- Description
+<b> Description</b>
2 The memset function copies the value of c (converted to an unsigned char) into
each of the first n characters of the object pointed to by s.
- Returns
+<b> Returns</b>
3 The memset function returns the value of s.
-
-
-[<a name="#p368" href="p368">page 368</a>] (<a href="#Contents">Contents</a>)
+[<a name="p368" href="#p368">page 368</a>] (<a href="#Contents">Contents</a>)
<a name="7.23.6.2" href="#7.23.6.2"><b> 7.23.6.2 The strerror function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
char *strerror(int errnum);
- Description
+<b> Description</b>
2 The strerror function maps the number in errnum to a message string. Typically,
the values for errnum come from errno, but strerror shall map any value of type
int to a message.
3 The strerror function is not required to avoid data races. The implementation shall
behave as if no library function calls the strerror function.
- Returns
+<b> Returns</b>
4 The strerror function returns a pointer to the string, the contents of which are locale-
specific. The array pointed to shall not be modified by the program, but may be
overwritten by a subsequent call to the strerror function.
<a name="7.23.6.3" href="#7.23.6.3"><b> 7.23.6.3 The strlen function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.23"><string.h></a>
size_t strlen(const char *s);
- Description
+<b> Description</b>
2 The strlen function computes the length of the string pointed to by s.
- Returns
+<b> Returns</b>
3 The strlen function returns the number of characters that precede the terminating null
character.
-
-
-
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+[<a name="p369" href="#p369">page 369</a>] (<a href="#Contents">Contents</a>)
<a name="7.24" href="#7.24"><b> 7.24 Type-generic math <tgmath.h></b></a>
1 The header <a href="#7.24"><tgmath.h></a> includes the headers <a href="#7.12"><math.h></a> and <a href="#7.3"><complex.h></a> and
2 Of the <a href="#7.12"><math.h></a> and <a href="#7.3"><complex.h></a> functions without an f (float) or l (long
double) suffix, several have one or more parameters whose corresponding real type is
double. For each such function, except modf, there is a corresponding type-generic
- macro.304) The parameters whose corresponding real type is double in the function
+ macro.<sup><a href="#note304"><b>304)</b></a></sup> The parameters whose corresponding real type is double in the function
synopsis are generic parameters. Use of the macro invokes a function whose
corresponding real type and type domain are determined by the arguments for the generic
- parameters.305)
+ parameters.<sup><a href="#note305"><b>305)</b></a></sup>
3 Use of the macro invokes a function whose generic parameters have the corresponding
real type determined as follows:
-- First, if any argument for generic parameters has type long double, the type
- 304) Like other function-like macros in Standard libraries, each type-generic macro can be suppressed to
+ <sup><a name="note304" href="#note304"><b>304)</b></a></sup> Like other function-like macros in Standard libraries, each type-generic macro can be suppressed to
make available the corresponding ordinary function.
- 305) If the type of the argument is not compatible with the type of the parameter for the selected function,
+ <sup><a name="note305" href="#note305"><b>305)</b></a></sup> If the type of the argument is not compatible with the type of the parameter for the selected function,
the behavior is undefined.
-[<a name="
#p370" href="p370">page 370</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p370" href="#p370">page 370</a>] (<a href="#Contents">Contents</a>)
<a href="#7.12"><math.h></a> <a href="#7.3"><complex.h></a> type-generic
function function macro
If all arguments for generic parameters are real, then use of the macro invokes a real
function; otherwise, use of the macro results in undefined behavior.
-
-
-
-[<a name="#p371" href="p371">page 371</a>] (<a href="#Contents">Contents</a>)
+[<a name="p371" href="#p371">page 371</a>] (<a href="#Contents">Contents</a>)
6 For each unsuffixed function in <a href="#7.3"><complex.h></a> that is not a c-prefixed counterpart to a
function in <a href="#7.12"><math.h></a>, the corresponding type-generic macro has the same name as the
carg(dc) carg(dc), the function
cproj(ldc) cprojl(ldc)
-
-
-
-[<a name="#p372" href="p372">page 372</a>] (<a href="#Contents">Contents</a>)
+[<a name="p372" href="#p372">page 372</a>] (<a href="#Contents">Contents</a>)
<a name="7.25" href="#7.25"><b> 7.25 Threads <threads.h></b></a>
<a name="7.25.1" href="#7.25.1"><b> 7.25.1 Introduction</b></a>
once_flag
which is a complete object type that holds a flag for use by call_once; and
-
-[<a name="#p373" href="p373">page 373</a>] (<a href="#Contents">Contents</a>)
+[<a name="p373" href="#p373">page 373</a>] (<a href="#Contents">Contents</a>)
xtime
which is a structure type that holds a time specified in seconds and nanoseconds. The
which is returned by a function to indicate that the requested operation failed because it
was unable to allocate memory.
-
-
-
-[<a name="#p374" href="p374">page 374</a>] (<a href="#Contents">Contents</a>)
+[<a name="p374" href="#p374">page 374</a>] (<a href="#Contents">Contents</a>)
<a name="7.25.2" href="#7.25.2"><b> 7.25.2 Initialization functions</b></a>
<a name="7.25.2.1" href="#7.25.2.1"><b> 7.25.2.1 The call_once function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
void call_once(once_flag *flag, void (*func)(void));
- Description
+<b> Description</b>
2 The call_once function uses the once_flag pointed to by flag to ensure that
func is called exactly once, the first time the call_once function is called with that
value of flag. Completion of an effective call to the call_once function synchronizes
with all subsequent calls to the call_once function with the same value of flag.
- Returns
+<b> Returns</b>
3 The call_once function returns no value.
<a name="7.25.3" href="#7.25.3"><b> 7.25.3 Condition variable functions</b></a>
<a name="7.25.3.1" href="#7.25.3.1"><b> 7.25.3.1 The cnd_broadcast function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int cnd_broadcast(cnd_t *cond);
- Description
+<b> Description</b>
2 The cnd_broadcast function unblocks all of the threads that are blocked on the
condition variable pointed to by cond at the time of the call. If no threads are blocked
on the condition variable pointed to by cond at the time of the call, the function does
nothing.
- Returns
+<b> Returns</b>
3 The cnd_broadcast function returns thrd_success on success, or thrd_error
if the request could not be honored.
<a name="7.25.3.2" href="#7.25.3.2"><b> 7.25.3.2 The cnd_destroy function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
void cnd_destroy(cnd_t *cond);
- Description
+<b> Description</b>
2 The cnd_destroy function releases all resources used by the condition variable
pointed to by cond. The cnd_destroy function requires that no threads be blocked
waiting for the condition variable pointed to by cond.
-[<a name="
#p375" href="p375">page 375</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p375" href="#p375">page 375</a>] (<a href="#Contents">Contents</a>)
- Returns
+<b> Returns</b>
3 The cnd_destroy function returns no value.
<a name="7.25.3.3" href="#7.25.3.3"><b> 7.25.3.3 The cnd_init function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int cnd_init(cnd_t *cond);
- Description
+<b> Description</b>
2 The cnd_init function creates a condition variable. If it succeeds it sets the variable
pointed to by cond to a value that uniquely identifies the newly created condition
variable. A thread that calls cnd_wait on a newly created condition variable will
block.
- Returns
+<b> Returns</b>
3 The cnd_init function returns thrd_success on success, or thrd_nomem if no
memory could be allocated for the newly created condition, or thrd_error if the
request could not be honored.
<a name="7.25.3.4" href="#7.25.3.4"><b> 7.25.3.4 The cnd_signal function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int cnd_signal(cnd_t *cond);
- Description
+<b> Description</b>
2 The cnd_signal function unblocks one of the threads that are blocked on the
condition variable pointed to by cond at the time of the call. If no threads are blocked
on the condition variable at the time of the call, the function does nothing and return
success.
- Returns
+<b> Returns</b>
3 The cnd_signal function returns thrd_success on success or thrd_error if
the request could not be honored.
<a name="7.25.3.5" href="#7.25.3.5"><b> 7.25.3.5 The cnd_timedwait function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int cnd_timedwait(cnd_t *cond, mtx_t *mtx,
const xtime *xt);
+[<a name="p376" href="#p376">page 376</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p376" href="p376">page 376</a>] (<a href="#Contents">Contents</a>)
-
- Description
+<b> Description</b>
2 The cnd_timedwait function atomically unlocks the mutex pointed to by mtx and
endeavors to block until the condition variable pointed to by cond is signaled by a call to
cnd_signal or to cnd_broadcast, or until after the time specified by the xtime
object pointed to by xt. When the calling thread becomes unblocked it locks the variable
pointed to by mtx before it returns. The cnd_timedwait function requires that the
mutex pointed to by mtx be locked by the calling thread.
- Returns
+<b> Returns</b>
3 The cnd_timedwait function returns thrd_success upon success, or
thrd_timeout if the time specified in the call was reached without acquiring the
requested resource, or thrd_error if the request could not be honored.
<a name="7.25.3.6" href="#7.25.3.6"><b> 7.25.3.6 The cnd_wait function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int cnd_wait(cnd_t *cond, mtx_t *mtx);
- Description
+<b> Description</b>
2 The cnd_wait function atomically unlocks the mutex pointed to by mtx and endeavors
to block until the condition variable pointed to by cond is signaled by a call to
cnd_signal or to cnd_broadcast. When the calling thread becomes unblocked it
locks the mutex pointed to by mtx before it returns. If the mutex pointed to by mtx is
not locked by the calling thread, the cnd_wait function will act as if the abort
function is called.
- Returns
+<b> Returns</b>
3 The cnd_wait function returns thrd_success on success or thrd_error if the
request could not be honored.
<a name="7.25.4" href="#7.25.4"><b> 7.25.4 Mutex functions</b></a>
<a name="7.25.4.1" href="#7.25.4.1"><b> 7.25.4.1 The mtx_destroy function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
void mtx_destroy(mtx_t *mtx);
- Description
+<b> Description</b>
2 The mtx_destroy function releases any resources used by the mutex pointed to by
mtx. No threads can be blocked waiting for the mutex pointed to by mtx.
+[<a name="p377" href="#p377">page 377</a>] (<a href="#Contents">Contents</a>)
-
-[<a name="#p377" href="p377">page 377</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The mtx_destroy function returns no value.
<a name="7.25.4.2" href="#7.25.4.2"><b> 7.25.4.2 The mtx_init function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int mtx_init(mtx_t *mtx, int type);
- Description
+<b> Description</b>
2 The mtx_init function creates a mutex object with properties indicated by type,
which must have one of the six values:
mtx_plain for a simple non-recursive mutex,
mtx_try | mtx_recursive for a recursive mutex that supports test and return.
3 If the mtx_init function succeeds, it sets the mutex pointed to by mtx to a value that
uniquely identifies the newly created mutex.
- Returns
+<b> Returns</b>
4 The mtx_init function returns thrd_success on success, or thrd_error if the
request could not be honored.
<a name="7.25.4.3" href="#7.25.4.3"><b> 7.25.4.3 The mtx_lock function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int mtx_lock(mtx_t *mtx);
- Description
+<b> Description</b>
2 The mtx_lock function blocks until it locks the mutex pointed to by mtx. If the mutex
is non-recursive, it shall not be locked by the calling thread. Prior calls to mtx_unlock
on the same mutex shall synchronize with this operation.
- Returns
+<b> Returns</b>
3 The mtx_lock function returns thrd_success on success, or thrd_busy if the
resource requested is already in use, or thrd_error if the request could not be
honored.
-
-
-
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+[<a name="p378" href="#p378">page 378</a>] (<a href="#Contents">Contents</a>)
<a name="7.25.4.4" href="#7.25.4.4"><b> 7.25.4.4 The mtx_timedlock function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int mtx_timedlock(mtx_t *mtx, const xtime *xt);
- Description
+<b> Description</b>
2 The mtx_timedlock function endeavors to block until it locks the mutex pointed to by
mtx or until the time specified by the xtime object xt has passed. The specified mutex
shall support timeout. If the operation succeeds, prior calls to mtx_unlock on the same
mutex shall synchronize with this operation.
- Returns
+<b> Returns</b>
3 The mtx_timedlock function returns thrd_success on success, or thrd_busy
if the resource requested is already in use, or thrd_timeout if the time specified was
reached without acquiring the requested resource, or thrd_error if the request could
not be honored.
<a name="7.25.4.5" href="#7.25.4.5"><b> 7.25.4.5 The mtx_trylock function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int mtx_trylock(mtx_t *mtx);
- Description
+<b> Description</b>
2 The mtx_trylock function endeavors to lock the mutex pointed to by mtx. The
specified mutex shall support either test and return or timeout. If the mutex is already
locked, the function returns without blocking. If the operation succeeds, prior calls to
mtx_unlock on the same mutex shall synchronize with this operation.
- Returns
+<b> Returns</b>
3 The mtx_trylock function returns thrd_success on success, or thrd_busy if
the resource requested is already in use, or thrd_error if the request could not be
honored.
<a name="7.25.4.6" href="#7.25.4.6"><b> 7.25.4.6 The mtx_unlock function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int mtx_unlock(mtx_t *mtx);
- Description
+<b> Description</b>
2 The mtx_unlock function unlocks the mutex pointed to by mtx. The mutex pointed to
by mtx shall be locked by the calling thread.
-[<a name="
#p379" href="p379">page 379</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p379" href="#p379">page 379</a>] (<a href="#Contents">Contents</a>)
- Returns
+<b> Returns</b>
3 The mtx_unlock function returns thrd_success on success or thrd_error if
the request could not be honored.
<a name="7.25.5" href="#7.25.5"><b> 7.25.5 Thread functions</b></a>
<a name="7.25.5.1" href="#7.25.5.1"><b> 7.25.5.1 The thrd_create function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int thrd_create(thrd_t *thr, thrd_start_t func,
void *arg);
- Description
+<b> Description</b>
2 The thrd_create function creates a new thread executing func(arg). If the
thrd_create function succeeds, it sets the object pointed to by thr to the identifier of
the newly created thread. (A thread's identifier may be reused for a different thread once
the original thread has exited and either been detached or joined to another thread.) The
completion of the thrd_create function synchronizes with the beginning of the
execution of the new thread.
- Returns
+<b> Returns</b>
3 The thrd_create function returns thrd_success on success, or thrd_nomem if
no memory could be allocated for the thread requested, or thrd_error if the request
could not be honored.
<a name="7.25.5.2" href="#7.25.5.2"><b> 7.25.5.2 The thrd_current function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
thrd_t thrd_current(void);
- Description
+<b> Description</b>
2 The thrd_current function identifies the thread that called it.
- Returns
+<b> Returns</b>
3 The thrd_current function returns the identifier of the thread that called it.
<a name="7.25.5.3" href="#7.25.5.3"><b> 7.25.5.3 The thrd_detach function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int thrd_detach(thrd_t thr);
+[<a name="p380" href="#p380">page 380</a>] (<a href="#Contents">Contents</a>)
-
-[<a name="#p380" href="p380">page 380</a>] (<a href="#Contents">Contents</a>)
-
- Description
+<b> Description</b>
2 The thrd_detach function tells the operating system to dispose of any resources
allocated to the thread identified by thr when that thread terminates. The thread
identified by thr shall not have been previously detached or joined with another thread.
- Returns
+<b> Returns</b>
3 The thrd_detach function returns thrd_success on success or thrd_error if
the request could not be honored.
<a name="7.25.5.4" href="#7.25.5.4"><b> 7.25.5.4 The thrd_equal function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int thrd_equal(thrd_t thr0, thrd_t thr1);
- Description
+<b> Description</b>
2 The thrd_equal function will determine whether the thread identified by thr0 refers
to the thread identified by thr1.
- Returns
+<b> Returns</b>
3 The thrd_equal function returns zero if the thread thr0 and the thread thr1 refer to
different threads. Otherwise the thrd_equal function returns a nonzero value.
<a name="7.25.5.5" href="#7.25.5.5"><b> 7.25.5.5 The thrd_exit function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
void thrd_exit(int res);
- Description
+<b> Description</b>
2 The thrd_exit function terminates execution of the calling thread and sets its result
code to res.
- Returns
+<b> Returns</b>
3 The thrd_exit function returns no value.
<a name="7.25.5.6" href="#7.25.5.6"><b> 7.25.5.6 The thrd_join function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int thrd_join(thrd_t thr, int *res);
- Description
+<b> Description</b>
2 The thrd_join function joins the thread identified by thr with the current thread by
blocking until the other thread has terminated. If the parameter res is not a null pointer,
-[<a name="
#p381" href="p381">page 381</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p381" href="#p381">page 381</a>] (<a href="#Contents">Contents</a>)
it stores the thread's result code in the integer pointed to by res. The termination of the
other thread synchronizes with the completion of the thrd_join function. The thread
identified by thr shall not have been previously detached or joined with another thread.
- Returns
+<b> Returns</b>
3 The thrd_join function returns thrd_success on success or thrd_error if the
request could not be honored.
<a name="7.25.5.7" href="#7.25.5.7"><b> 7.25.5.7 The thrd_sleep function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
void thrd_sleep(const xtime *xt);
- Description
+<b> Description</b>
2 The thrd_sleep function suspends execution of the calling thread until after the time
specified by the xtime object pointed to by xt.
- Returns
+<b> Returns</b>
3 The thrd_sleep function returns no value.
<a name="7.25.5.8" href="#7.25.5.8"><b> 7.25.5.8 The thrd_yield function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
void thrd_yield(void);
- Description
+<b> Description</b>
2 The thrd_yield function endeavors to permit other threads to run, even if the current
thread would ordinarily continue to run.
- Returns
+<b> Returns</b>
3 The thrd_yield function returns no value.
<a name="7.25.6" href="#7.25.6"><b> 7.25.6 Thread-specific storage functions</b></a>
<a name="7.25.6.1" href="#7.25.6.1"><b> 7.25.6.1 The tss_create function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int tss_create(tss_t *key, tss_dtor_t dtor);
- Description
+<b> Description</b>
2 The tss_create function creates a thread-specific storage pointer with destructor
dtor, which may be null.
+[<a name="p382" href="#p382">page 382</a>] (<a href="#Contents">Contents</a>)
-[<a name="#p382" href="p382">page 382</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 If the tss_create function is successful, it sets the thread-specific storage pointed to
by key to a value that uniquely identifies the newly created pointer and returns
thrd_success; otherwise, thrd_error is returned and the thread-specific storage
pointed to by key is set to an undefined value.
<a name="7.25.6.2" href="#7.25.6.2"><b> 7.25.6.2 The tss_delete function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
void tss_delete(tss_t key);
- Description
+<b> Description</b>
2 The tss_delete function releases any resources used by the thread-specific storage
identified by key.
- Returns
+<b> Returns</b>
3 The tss_delete function returns no value.
<a name="7.25.6.3" href="#7.25.6.3"><b> 7.25.6.3 The tss_get function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
void *tss_get(tss_t key);
- Description
+<b> Description</b>
2 The tss_get function returns the value for the current thread held in the thread-specific
storage identified by key.
- Returns
+<b> Returns</b>
3 The tss_get function returns the value for the current thread if successful, or zero if
unsuccessful.
<a name="7.25.6.4" href="#7.25.6.4"><b> 7.25.6.4 The tss_set function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int tss_set(tss_t key, void *val);
- Description
+<b> Description</b>
2 The tss_set function sets the value for the current thread held in the thread-specific
storage identified by key to val.
+[<a name="p383" href="#p383">page 383</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p383" href="p383">page 383</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The tss_set function returns thrd_success on success or thrd_error if the
request could not be honored.
<a name="7.25.7" href="#7.25.7"><b> 7.25.7 Time functions</b></a>
<a name="7.25.7.1" href="#7.25.7.1"><b> 7.25.7.1 The xtime_get function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.25"><threads.h></a>
int xtime_get(xtime *xt, int base);
- Description
+<b> Description</b>
2 The xtime_get function sets the xtime object pointed to by xt to hold the current
time based on the time base base.
- Returns
+<b> Returns</b>
3 If the xtime_get function is successful it returns the nonzero value base, which must
- be TIME_UTC; otherwise, it returns zero.306)
+ be TIME_UTC; otherwise, it returns zero.<sup><a href="#note306"><b>306)</b></a></sup>
- 306) Although an xtime object describes times with nanosecond resolution, the actual resolution in an
+ <sup><a name="note306" href="#note306"><b>306)</b></a></sup> Although an xtime object describes times with nanosecond resolution, the actual resolution in an
xtime object is system dependent.
-[<a name="
#p384" href="p384">page 384</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p384" href="#p384">page 384</a>] (<a href="#Contents">Contents</a>)
<a name="7.26" href="#7.26"><b> 7.26 Date and time <time.h></b></a>
<a name="7.26.1" href="#7.26.1"><b> 7.26.1 Components of time</b></a>
4 The range and precision of times representable in clock_t and time_t are
implementation-defined. The tm structure shall contain at least the following members,
in any order. The semantics of the members and their normal ranges are expressed in the
- comments.307)
+ comments.<sup><a href="#note307"><b>307)</b></a></sup>
int tm_sec; // seconds after the minute -- [0, 60]
int tm_min; // minutes after the hour -- [0, 59]
int tm_hour; // hours since midnight -- [0, 23]
- 307) The range [0, 60] for tm_sec allows for a positive leap second.
+ <sup><a name="note307" href="#note307"><b>307)</b></a></sup> The range [0, 60] for tm_sec allows for a positive leap second.
-[<a name="
#p385" href="p385">page 385</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p385" href="#p385">page 385</a>] (<a href="#Contents">Contents</a>)
The value of tm_isdst is positive if Daylight Saving Time is in effect, zero if Daylight
Saving Time is not in effect, and negative if the information is not available.
<a name="7.26.2" href="#7.26.2"><b> 7.26.2 Time manipulation functions</b></a>
<a name="7.26.2.1" href="#7.26.2.1"><b> 7.26.2.1 The clock function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.26"><time.h></a>
clock_t clock(void);
- Description
+<b> Description</b>
2 The clock function determines the processor time used.
- Returns
+<b> Returns</b>
3 The clock function returns the implementation's best approximation to the processor
time used by the program since the beginning of an implementation-defined era related
only to the program invocation. To determine the time in seconds, the value returned by
the clock function should be divided by the value of the macro CLOCKS_PER_SEC. If
the processor time used is not available or its value cannot be represented, the function
- returns the value (clock_t)(-1).308)
+ returns the value (clock_t)(-1).<sup><a href="#note308"><b>308)</b></a></sup>
<a name="7.26.2.2" href="#7.26.2.2"><b> 7.26.2.2 The difftime function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.26"><time.h></a>
double difftime(time_t time1, time_t time0);
- Description
+<b> Description</b>
2 The difftime function computes the difference between two calendar times: time1 -
time0.
- Returns
+<b> Returns</b>
3 The difftime function returns the difference expressed in seconds as a double.
- 308) In order to measure the time spent in a program, the clock function should be called at the start of
+ <sup><a name="note308" href="#note308"><b>308)</b></a></sup> In order to measure the time spent in a program, the clock function should be called at the start of
the program and its return value subtracted from the value returned by subsequent calls.
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+[<a name="
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<a name="7.26.2.3" href="#7.26.2.3"><b> 7.26.2.3 The mktime function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.26"><time.h></a>
time_t mktime(struct tm *timeptr);
- Description
+<b> Description</b>
2 The mktime function converts the broken-down time, expressed as local time, in the
structure pointed to by timeptr into a calendar time value with the same encoding as
that of the values returned by the time function. The original values of the tm_wday
and tm_yday components of the structure are ignored, and the original values of the
- other components are not restricted to the ranges indicated above.309) On successful
+ other components are not restricted to the ranges indicated above.<sup><a href="#note309"><b>309)</b></a></sup> On successful
completion, the values of the tm_wday and tm_yday components of the structure are
set appropriately, and the other components are set to represent the specified calendar
time, but with their values forced to the ranges indicated above; the final value of
tm_mday is not set until tm_mon and tm_year are determined.
- Returns
+<b> Returns</b>
3 The mktime function returns the specified calendar time encoded as a value of type
time_t. If the calendar time cannot be represented, the function returns the value
(time_t)(-1).
- 309) Thus, a positive or zero value for tm_isdst causes the mktime function to presume initially that
+ <sup><a name="note309" href="#note309"><b>309)</b></a></sup> Thus, a positive or zero value for tm_isdst causes the mktime function to presume initially that
Daylight Saving Time, respectively, is or is not in effect for the specified time. A negative value
causes it to attempt to determine whether Daylight Saving Time is in effect for the specified time.
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time_str.tm_year = 2001 - 1900;
time_str.tm_mon = 7 - 1;
printf("%s\n", wday[time_str.tm_wday]);
<a name="7.26.2.4" href="#7.26.2.4"><b> 7.26.2.4 The time function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.26"><time.h></a>
time_t time(time_t *timer);
- Description
+<b> Description</b>
2 The time function determines the current calendar time. The encoding of the value is
unspecified.
- Returns
+<b> Returns</b>
3 The time function returns the implementation's best approximation to the current
calendar time. The value (time_t)(-1) is returned if the calendar time is not
available. If timer is not a null pointer, the return value is also assigned to the object it
previous call to any of them and the functions are not required to avoid data races. The
implementation shall behave as if no other library functions call these functions.
<a name="7.26.3.1" href="#7.26.3.1"><b> 7.26.3.1 The asctime function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.26"><time.h></a>
char *asctime(const struct tm *timeptr);
- Description
+<b> Description</b>
2 The asctime function converts the broken-down time in the structure pointed to by
timeptr into a string in the form
Sun Sep 16 01:03:52 1973\n\0
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using the equivalent of the following algorithm.
char *asctime(const struct tm *timeptr)
return result;
}
3 If any of the fields of the broken-down time contain values that are outside their normal
- ranges,310) the behavior of the asctime function is undefined. Likewise, if the
+ ranges,<sup><a href="#note310"><b>310)</b></a></sup> the behavior of the asctime function is undefined. Likewise, if the
calculated year exceeds four digits or is less than the year 1000, the behavior is
undefined.
- Returns
+<b> Returns</b>
4 The asctime function returns a pointer to the string.
<a name="7.26.3.2" href="#7.26.3.2"><b> 7.26.3.2 The ctime function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.26"><time.h></a>
char *ctime(const time_t *timer);
- Description
+<b> Description</b>
2 The ctime function converts the calendar time pointed to by timer to local time in the
form of a string. It is equivalent to
asctime(localtime(timer))
-
310) See <a href="#7.26.1">7.26.1</a>.
+
<sup><a name="note310" href="#note310"><b>310)</b></a></sup> See <a href="#7.26.1">7.26.1</a>.
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+[<a name="
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- Returns
+<b> Returns</b>
3 The ctime function returns the pointer returned by the asctime function with that
broken-down time as argument.
Forward references: the localtime function (<a href="#7.26.3.4">7.26.3.4</a>).
<a name="7.26.3.3" href="#7.26.3.3"><b> 7.26.3.3 The gmtime function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.26"><time.h></a>
struct tm *gmtime(const time_t *timer);
- Description
+<b> Description</b>
2 The gmtime function converts the calendar time pointed to by timer into a broken-
down time, expressed as UTC.
- Returns
+<b> Returns</b>
3 The gmtime function returns a pointer to the broken-down time, or a null pointer if the
specified time cannot be converted to UTC.
<a name="7.26.3.4" href="#7.26.3.4"><b> 7.26.3.4 The localtime function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.26"><time.h></a>
struct tm *localtime(const time_t *timer);
- Description
+<b> Description</b>
2 The localtime function converts the calendar time pointed to by timer into a
broken-down time, expressed as local time.
- Returns
+<b> Returns</b>
3 The localtime function returns a pointer to the broken-down time, or a null pointer if
the specified time cannot be converted to local time.
<a name="7.26.3.5" href="#7.26.3.5"><b> 7.26.3.5 The strftime function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.26"><time.h></a>
size_t strftime(char * restrict s,
size_t maxsize,
const char * restrict format,
const struct tm * restrict timeptr);
+[<a name="p390" href="#p390">page 390</a>] (<a href="#Contents">Contents</a>)
-
-
-[<a name="#p390" href="p390">page 390</a>] (<a href="#Contents">Contents</a>)
-
- Description
+<b> Description</b>
2 The strftime function places characters into the array pointed to by s as controlled by
the string pointed to by format. The format shall be a multibyte character sequence,
beginning and ending in its initial shift state. The format string consists of zero or
%M is replaced by the minute as a decimal number (00-59). [tm_min]
%n is replaced by a new-line character.
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%p is replaced by the locale's equivalent of the AM/PM designations associated with a
12-hour clock. [tm_hour]
%u is replaced by the ISO 8601 weekday as a decimal number (1-7), where Monday
is 1. [tm_wday]
%U is replaced by the week number of the year (the first Sunday as the first day of week
- 1) as a decimal number (00-53). [tm_year, tm_wday, tm_yday]
+ <sup><a name="note1" href="#note1"><b>1)</b></a></sup> as a decimal number (00-53). [tm_year, tm_wday, tm_yday]
%V is replaced by the ISO 8601 week number (see below) as a decimal number
(01-53). [tm_year, tm_wday, tm_yday]
%w is replaced by the weekday as a decimal number (0-6), where Sunday is 0.
representation.
%EY is replaced by the locale's full alternative year representation.
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%Od is replaced by the day of the month, using the locale's alternative numeric symbols
(filled as needed with leading zeros, or with leading spaces if there is no alternative
%b the first three characters of %B.
%B one of ''January'', ''February'', ... , ''December''.
%c equivalent to ''%a %b %e %T %Y''.
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+
+[<a name="p393" href="#p393">page 393</a>] (<a href="#Contents">Contents</a>)
%p one of ''AM'' or ''PM''.
%r equivalent to ''%I:%M:%S %p''.
%x equivalent to ''%m/%d/%y''.
%X equivalent to %T.
%Z implementation-defined.
- Returns
+<b> Returns</b>
8 If the total number of resulting characters including the terminating null character is not
more than maxsize, the strftime function returns the number of characters placed
into the array pointed to by s not including the terminating null character. Otherwise,
zero is returned and the contents of the array are indeterminate.
-
-
-
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<a name="7.27" href="#7.27"><b> 7.27 Unicode utilities <uchar.h></b></a>
1 The header <a href="#7.27"><uchar.h></a> declares types and functions for manipulating Unicode
to avoid data races in this case. The implementation behaves as if no library function
calls these functions with a null pointer for ps.
<a name="7.27.1.1" href="#7.27.1.1"><b> 7.27.1.1 The mbrtoc16 function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.27"><uchar.h></a>
size_t mbrtoc16(char16_t * restrict pc16,
const char * restrict s, size_t n,
mbstate_t * restrict ps);
- Description
+<b> Description</b>
2 If s is a null pointer, the mbrtoc16 function is equivalent to the call:
mbrtoc16(NULL, "", 1, ps)
In this case, the values of the parameters pc16 and n are ignored.
next multibyte character is complete and valid, it determines the values of the
corresponding wide characters and then, if pc16 is not a null pointer, stores the value of
the first (or only) such character in the object pointed to by pc16. Subsequent calls will
-[<a name="#p395" href="p395">page 395</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p395" href="#p395">page 395</a>] (<a href="#Contents">Contents</a>)
store successive wide characters without consuming any additional input until all the
characters have been stored. If the corresponding wide character is the null wide
character, the resulting state described is the initial conversion state.
- Returns
+<b> Returns</b>
4 The mbrtoc16 function returns the first of the following that applies (given the current
conversion state):
0 if the next n or fewer bytes complete the multibyte character that
bytes from the input have been consumed by this call).
(size_t)(-2) if the next n bytes contribute to an incomplete (but potentially valid)
multibyte character, and all n bytes have been processed (no value is
- stored).311)
+ stored).<sup><a href="#note311"><b>311)</b></a></sup>
(size_t)(-1) if an encoding error occurs, in which case the next n or fewer bytes
do not contribute to a complete and valid multibyte character (no
value is stored); the value of the macro EILSEQ is stored in errno,
and the conversion state is unspecified.
<a name="7.27.1.2" href="#7.27.1.2"><b> 7.27.1.2 The c16rtomb function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.27"><uchar.h></a>
size_t c16rtomb(char * restrict s, char16_t c16,
mbstate_t * restrict ps);
- Description
+<b> Description</b>
2 If s is a null pointer, the c16rtomb function is equivalent to the call
c16rtomb(buf, L'\0', ps)
where buf is an internal buffer.
(including any shift sequences), and stores the multibyte character representation in the
- 311) When n has at least the value of the MB_CUR_MAX macro, this case can only occur if s points at a
+ <sup><a name="note311" href="#note311"><b>311)</b></a></sup> When n has at least the value of the MB_CUR_MAX macro, this case can only occur if s points at a
sequence of redundant shift sequences (for implementations with state-dependent encodings).
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array whose first element is pointed to by s. At most MB_CUR_MAX bytes are stored. If
c16 is a null wide character, a null byte is stored, preceded by any shift sequence needed
to restore the initial shift state; the resulting state described is the initial conversion state.
- Returns
+<b> Returns</b>
4 The c16rtomb function returns the number of bytes stored in the array object (including
any shift sequences). When c16 is not a valid wide character, an encoding error occurs:
the function stores the value of the macro EILSEQ in errno and returns
(size_t)(-1); the conversion state is unspecified.
<a name="7.27.1.3" href="#7.27.1.3"><b> 7.27.1.3 The mbrtoc32 function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.27"><uchar.h></a>
size_t mbrtoc32(char32_t * restrict pc32,
const char * restrict s, size_t n,
mbstate_t * restrict ps);
- Description
+<b> Description</b>
2 If s is a null pointer, the mbrtoc32 function is equivalent to the call:
mbrtoc32(NULL, "", 1, ps)
In this case, the values of the parameters pc32 and n are ignored.
store successive wide characters without consuming any additional input until all the
characters have been stored. If the corresponding wide character is the null wide
character, the resulting state described is the initial conversion state.
- Returns
+<b> Returns</b>
4 The mbrtoc32 function returns the first of the following that applies (given the current
conversion state):
0 if the next n or fewer bytes complete the multibyte character that
character (which is the value stored); the value returned is the number
of bytes that complete the multibyte character.
-
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(size_t)(-3) if the next character resulting from a previous call has been stored (no
bytes from the input have been consumed by this call).
(size_t)(-2) if the next n bytes contribute to an incomplete (but potentially valid)
multibyte character, and all n bytes have been processed (no value is
- stored).312)
+ stored).<sup><a href="#note312"><b>312)</b></a></sup>
(size_t)(-1) if an encoding error occurs, in which case the next n or fewer bytes
do not contribute to a complete and valid multibyte character (no
value is stored); the value of the macro EILSEQ is stored in errno,
and the conversion state is unspecified.
<a name="7.27.1.4" href="#7.27.1.4"><b> 7.27.1.4 The c32rtomb function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.27"><uchar.h></a>
size_t c32rtomb(char * restrict s, char32_t c32,
mbstate_t * restrict ps);
- Description
+<b> Description</b>
2 If s is a null pointer, the c32rtomb function is equivalent to the call
c32rtomb(buf, L'\0', ps)
where buf is an internal buffer.
array whose first element is pointed to by s. At most MB_CUR_MAX bytes are stored. If
c32 is a null wide character, a null byte is stored, preceded by any shift sequence needed
to restore the initial shift state; the resulting state described is the initial conversion state.
- Returns
+<b> Returns</b>
4 The c32rtomb function returns the number of bytes stored in the array object (including
any shift sequences). When c32 is not a valid wide character, an encoding error occurs:
the function stores the value of the macro EILSEQ in errno and returns
- 312) When n has at least the value of the MB_CUR_MAX macro, this case can only occur if s points at a
+ <sup><a name="note312" href="#note312"><b>312)</b></a></sup> When n has at least the value of the MB_CUR_MAX macro, this case can only occur if s points at a
sequence of redundant shift sequences (for implementations with state-dependent encodings).
-[<a name="
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+[<a name="
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<a name="7.28" href="#7.28"><b> 7.28 Extended multibyte and wide character utilities <wchar.h></b></a>
<a name="7.28.1" href="#7.28.1"><b> 7.28.1 Introduction</b></a>
1 The header <a href="#7.28"><wchar.h></a> defines four macros, and declares four data types, one tag, and
- many functions.313)
+ many functions.<sup><a href="#note313"><b>313)</b></a></sup>
2 The types declared are wchar_t and size_t (both described in <a href="#7.19">7.19</a>);
mbstate_t
which is a complete object type other than an array type that can hold the conversion state
which is an integer type unchanged by default argument promotions that can hold any
value corresponding to members of the extended character set, as well as at least one
value that does not correspond to any member of the extended character set (see WEOF
- below);314) and
+ below);<sup><a href="#note314"><b>314)</b></a></sup> and
struct tm
which is declared as an incomplete structure type (the contents are described in <a href="#7.26.1">7.26.1</a>).
3 The macros defined are NULL (described in <a href="#7.19">7.19</a>); WCHAR_MIN and WCHAR_MAX
(described in <a href="#7.20.3">7.20.3</a>); and
WEOF
which expands to a constant expression of type wint_t whose value does not
- correspond to any member of the extended character set.315) It is accepted (and returned)
+ correspond to any member of the extended character set.<sup><a href="#note315"><b>315)</b></a></sup> It is accepted (and returned)
by several functions in this subclause to indicate end-of-file, that is, no more input from a
stream. It is also used as a wide character value that does not correspond to any member
of the extended character set.
-- Functions that perform general wide string manipulation;
-
313) See ''future library directions'' (<a href="#7.30.12">7.30.12</a>).
- 314) wchar_t and wint_t can be the same integer type.
- 315) The value of the macro WEOF may differ from that of EOF and need not be negative.
+
<sup><a name="note313" href="#note313"><b>313)</b></a></sup> See ''future library directions'' (<a href="#7.30.12">7.30.12</a>).
+ <sup><a name="note314" href="#note314"><b>314)</b></a></sup> wchar_t and wint_t can be the same integer type.
+ <sup><a name="note315" href="#note315"><b>315)</b></a></sup> The value of the macro WEOF may differ from that of EOF and need not be negative.
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-- Functions for wide string date and time conversion; and
-- Functions that provide extended capabilities for conversion between multibyte and
undefined.
<a name="7.28.2" href="#7.28.2"><b> 7.28.2 Formatted wide character input/output functions</b></a>
1 The formatted wide character input/output functions shall behave as if there is a sequence
- point after the actions associated with each specifier.316)
+ point after the actions associated with each specifier.<sup><a href="#note316"><b>316)</b></a></sup>
<a name="7.28.2.1" href="#7.28.2.1"><b> 7.28.2.1 The fwprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
int fwprintf(FILE * restrict stream,
const wchar_t * restrict format, ...);
- Description
+<b> Description</b>
2 The fwprintf function writes output to the stream pointed to by stream, under
control of the wide string pointed to by format that specifies how subsequent arguments
are converted for output. If there are insufficient arguments for the format, the behavior
than the field width, it is padded with spaces (by default) on the left (or right, if the
- 316) The fwprintf functions perform writes to memory for the %n specifier.
+ <sup><a name="note316" href="#note316"><b>316)</b></a></sup> The fwprintf functions perform writes to memory for the %n specifier.
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left adjustment flag, described later, has been given) to the field width. The field
width takes the form of an asterisk * (described later) or a nonnegative decimal
- integer.317)
+ integer.<sup><a href="#note317"><b>317)</b></a></sup>
-- An optional precision that gives the minimum number of digits to appear for the d, i,
o, u, x, and X conversions, the number of digits to appear after the decimal-point
wide character for a, A, e, E, f, and F conversions, the maximum number of
this flag is not specified.)
+ The result of a signed conversion always begins with a plus or minus sign. (It
begins with a sign only when a negative value is converted if this flag is not
- specified.)318)
+ specified.)<sup><a href="#note318"><b>318)</b></a></sup>
space If the first wide character of a signed conversion is not a sign, or if a signed
conversion results in no wide characters, a space is prefixed to the result. If the
space and + flags both appear, the space flag is ignored.
conversion, a nonzero result has 0x (or 0X) prefixed to it. For a, A, e, E, f, F, g,
- 317) Note that 0 is taken as a flag, not as the beginning of a field width.
- 318) The results of all floating conversions of a negative zero, and of negative values that round to zero,
+ <sup><a name="note317" href="#note317"><b>317)</b></a></sup> Note that 0 is taken as a flag, not as the beginning of a field width.
+ <sup><a name="note318" href="#note318"><b>318)</b></a></sup> The results of all floating conversions of a negative zero, and of negative values that round to zero,
include a minus sign.
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and G conversions, the result of converting a floating-point number always
contains a decimal-point wide character, even if no digits follow it. (Normally, a
an intmax_t or uintmax_t argument; or that a following n conversion
specifier applies to a pointer to an intmax_t argument.
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z Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
size_t or the corresponding signed integer type argument; or that a
any n-wchar-sequence, is implementation-defined. The F conversion
specifier produces INF, INFINITY, or NAN instead of inf, infinity, or
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- nan, respectively.319)
+ nan, respectively.<sup><a href="#note319"><b>319)</b></a></sup>
e,E A double argument representing a floating-point number is converted in the
style [-]d.ddd e(+-)dd, where there is one digit (which is nonzero if the
argument is nonzero) before the decimal-point wide character and the number
a,A A double argument representing a floating-point number is converted in the
style [-]0xh.hhhh p(+-)d, where there is one hexadecimal digit (which is
nonzero if the argument is a normalized floating-point number and is
- otherwise unspecified) before the decimal-point wide character320) and the
+ otherwise unspecified) before the decimal-point wide character<sup><a href="#note320"><b>320)</b></a></sup> and the
number of hexadecimal digits after it is equal to the precision; if the precision
is missing and FLT_RADIX is a power of 2, then the precision is sufficient
-319) When applied to infinite and NaN values, the -, +, and space flag wide characters have their usual
+<sup><a name="note319" href="#note319"><b>319)</b></a></sup> When applied to infinite and NaN values, the -, +, and space flag wide characters have their usual
meaning; the # and 0 flag wide characters have no effect.
-320) Binary implementations can choose the hexadecimal digit to the left of the decimal-point wide
+<sup><a name="note320" href="#note320"><b>320)</b></a></sup> Binary implementations can choose the hexadecimal digit to the left of the decimal-point wide
character so that subsequent digits align to nibble (4-bit) boundaries.
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+[<a name="
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for an exact representation of the value; if the precision is missing and
FLT_RADIX is not a power of 2, then the precision is sufficient to
- distinguish321) values of type double, except that trailing zeros may be
+ distinguish<sup><a href="#note321"><b>321)</b></a></sup> values of type double, except that trailing zeros may be
omitted; if the precision is zero and the # flag is not specified, no decimal-
point wide character appears. The letters abcdef are used for a conversion
and the letters ABCDEF for A conversion. The A conversion specifier
p The argument shall be a pointer to void. The value of the pointer is
converted to a sequence of printing wide characters, in an implementation-
-321) The precision p is sufficient to distinguish values of the source type if 16 p-1 > b n where b is
+<sup><a name="note321" href="#note321"><b>321)</b></a></sup> The precision p is sufficient to distinguish values of the source type if 16 p-1 > b n where b is
FLT_RADIX and n is the number of base-b digits in the significand of the source type. A smaller p
might suffice depending on the implementation's scheme for determining the digit to the left of the
decimal-point wide character.
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defined manner.
n The argument shall be a pointer to signed integer into which is written the
behavior is undefined.
% A % wide character is written. No argument is converted. The complete
conversion specification shall be %%.
-9 If a conversion specification is invalid, the behavior is undefined.322) If any argument is
+9 If a conversion specification is invalid, the behavior is undefined.<sup><a href="#note322"><b>322)</b></a></sup> If any argument is
not the correct type for the corresponding conversion specification, the behavior is
undefined.
10 In no case does a nonexistent or small field width cause truncation of a field; if the result
in hexadecimal floating style with the given precision, with the extra stipulation that the
error should have a correct sign for the current rounding direction.
13 For e, E, f, F, g, and G conversions, if the number of significant decimal digits is at most
- DECIMAL_DIG, then the result should be correctly rounded.323) If the number of
+ DECIMAL_DIG, then the result should be correctly rounded.<sup><a href="#note323"><b>323)</b></a></sup> If the number of
significant decimal digits is more than DECIMAL_DIG but the source value is exactly
representable with DECIMAL_DIG digits, then the result should be an exact
representation with trailing zeros. Otherwise, the source value is bounded by two
adjacent decimal strings L < U, both having DECIMAL_DIG significant digits; the value
of the resultant decimal string D should satisfy L <= D <= U, with the extra stipulation that
the error should have a correct sign for the current rounding direction.
- Returns
+<b> Returns</b>
14 The fwprintf function returns the number of wide characters transmitted, or a negative
value if an output or encoding error occurred.
-
322) See ''future library directions'' (<a href="#7.30.12">7.30.12</a>).
- 323) For binary-to-decimal conversion, the result format's values are the numbers representable with the
+
<sup><a name="note322" href="#note322"><b>322)</b></a></sup> See ''future library directions'' (<a href="#7.30.12">7.30.12</a>).
+ <sup><a name="note323" href="#note323"><b>323)</b></a></sup> For binary-to-decimal conversion, the result format's values are the numbers representable with the
given format specifier. The number of significant digits is determined by the format specifier, and in
the case of fixed-point conversion by the source value as well.
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Environmental limits
15 The number of wide characters that can be produced by any single conversion shall be at
int day, hour, min;
fwprintf(stdout, L"%ls, %ls %d, %.2d:%.2d\n",
weekday, month, day, hour, min);
- fwprintf(stdout, L"pi = %.5f\n", 4 * atan(<a href="#1.0">1.0</a>));
+ fwprintf(stdout, L"pi = %.5f\n", 4 * atan(1.0));
Forward references: the btowc function (<a href="#7.28.6.1.1">7.28.6.1.1</a>), the mbrtowc function
(<a href="#7.28.6.3.2">7.28.6.3.2</a>).
<a name="7.28.2.2" href="#7.28.2.2"><b> 7.28.2.2 The fwscanf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
int fwscanf(FILE * restrict stream,
const wchar_t * restrict format, ...);
- Description
+<b> Description</b>
2 The fwscanf function reads input from the stream pointed to by stream, under
control of the wide string pointed to by format that specifies the admissible input
sequences and how they are to be converted for assignment, using subsequent arguments
-- An optional decimal integer greater than zero that specifies the maximum field width
(in wide characters).
-
-
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-- An optional length modifier that specifies the size of the receiving object.
-- A conversion specifier wide character that specifies the type of conversion to be
described below for each specifier. A conversion specification is executed in the
following steps:
8 Input white-space wide characters (as specified by the iswspace function) are skipped,
- unless the specification includes a [, c, or n specifier.324)
+ unless the specification includes a [, c, or n specifier.<sup><a href="#note324"><b>324)</b></a></sup>
9 An input item is read from the stream, unless the specification includes an n specifier. An
input item is defined as the longest sequence of input wide characters which does not
exceed any specified field width and which is, or is a prefix of, a matching input
- sequence.325) The first wide character, if any, after the input item remains unread. If the
+ sequence.<sup><a href="#note325"><b>325)</b></a></sup> The first wide character, if any, after the input item remains unread. If the
length of the input item is zero, the execution of the directive fails; this condition is a
matching failure unless end-of-file, an encoding error, or a read error prevented input
from the stream, in which case it is an input failure.
following the format argument that has not already received a conversion result. If this
- 324) These white-space wide characters are not counted against a specified field width.
- 325) fwscanf pushes back at most one input wide character onto the input stream. Therefore, some
+ <sup><a name="note324" href="#note324"><b>324)</b></a></sup> These white-space wide characters are not counted against a specified field width.
+ <sup><a name="note325" href="#note325"><b>325)</b></a></sup> fwscanf pushes back at most one input wide character onto the input stream. Therefore, some
sequences that are acceptable to wcstod, wcstol, etc., are unacceptable to fwscanf.
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object does not have an appropriate type, or if the result of the conversion cannot be
represented in the object, the behavior is undefined.
for the subject sequence of the wcstol function with the value 0 for the
base argument. The corresponding argument shall be a pointer to signed
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+[<a name="
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integer.
o Matches an optionally signed octal integer, whose format is the same as
If an l length modifier is present, the corresponding argument shall be a
pointer to the initial element of an array of wchar_t large enough to accept
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the sequence and the terminating null wide character, which will be added
automatically.
from the input stream so far by this call to the fwscanf function. Execution
of a %n directive does not increment the assignment count returned at the
completion of execution of the fwscanf function. No argument is
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+
+[<a name="p411" href="#p411">page 411</a>] (<a href="#Contents">Contents</a>)
converted, but one is consumed. If the conversion specification includes an
assignment-suppressing wide character or a field width, the behavior is
undefined.
% Matches a single % wide character; no conversion or assignment occurs. The
complete conversion specification shall be %%.
-13 If a conversion specification is invalid, the behavior is undefined.326)
+13 If a conversion specification is invalid, the behavior is undefined.<sup><a href="#note326"><b>326)</b></a></sup>
14 The conversion specifiers A, E, F, G, and X are also valid and behave the same as,
respectively, a, e, f, g, and x.
15 Trailing white space (including new-line wide characters) is left unread unless matched
by a directive. The success of literal matches and suppressed assignments is not directly
determinable other than via the %n directive.
- Returns
+<b> Returns</b>
16 The fwscanf function returns the value of the macro EOF if an input failure occurs
before the first conversion (if any) has completed. Otherwise, the function returns the
number of input items assigned, which can be fewer than provided for, or even zero, in
56.0. The next wide character read from the input stream will be a.
-
326) See ''future library directions'' (<a href="#7.30.12">7.30.12</a>).
+
<sup><a name="note326" href="#note326"><b>326)</b></a></sup> See ''future library directions'' (<a href="#7.30.12">7.30.12</a>).
-[<a name="
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Forward references: the wcstod, wcstof, and wcstold functions (<a href="#7.28.4.1.1">7.28.4.1.1</a>), the
wcstol, wcstoll, wcstoul, and wcstoull functions (<a href="#7.28.4.1.2">7.28.4.1.2</a>), the wcrtomb
function (<a href="#7.28.6.3.3">7.28.6.3.3</a>).
<a name="7.28.2.3" href="#7.28.2.3"><b> 7.28.2.3 The swprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
int swprintf(wchar_t * restrict s,
size_t n,
const wchar_t * restrict format, ...);
- Description
+<b> Description</b>
2 The swprintf function is equivalent to fwprintf, except that the argument s
specifies an array of wide characters into which the generated output is to be written,
rather than written to a stream. No more than n wide characters are written, including a
terminating null wide character, which is always added (unless n is zero).
- Returns
+<b> Returns</b>
3 The swprintf function returns the number of wide characters written in the array, not
counting the terminating null wide character, or a negative value if an encoding error
occurred or if n or more wide characters were requested to be written.
<a name="7.28.2.4" href="#7.28.2.4"><b> 7.28.2.4 The swscanf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
int swscanf(const wchar_t * restrict s,
const wchar_t * restrict format, ...);
- Description
+<b> Description</b>
2 The swscanf function is equivalent to fwscanf, except that the argument s specifies a
wide string from which the input is to be obtained, rather than from a stream. Reaching
the end of the wide string is equivalent to encountering end-of-file for the fwscanf
function.
- Returns
+<b> Returns</b>
3 The swscanf function returns the value of the macro EOF if an input failure occurs
before the first conversion (if any) has completed. Otherwise, the swscanf function
returns the number of input items assigned, which can be fewer than provided for, or even
zero, in the event of an early matching failure.
-
-
-
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<a name="7.28.2.5" href="#7.28.2.5"><b> 7.28.2.5 The vfwprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
int vfwprintf(FILE * restrict stream,
const wchar_t * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vfwprintf function is equivalent to fwprintf, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vfwprintf function does not invoke the
- va_end macro.327)
- Returns
+ va_end macro.<sup><a href="#note327"><b>327)</b></a></sup>
+<b> Returns</b>
3 The vfwprintf function returns the number of wide characters transmitted, or a
negative value if an output or encoding error occurred.
4 EXAMPLE The following shows the use of the vfwprintf function in a general error-reporting
- 327) As the functions vfwprintf, vswprintf, vfwscanf, vwprintf, vwscanf, and vswscanf
+ <sup><a name="note327" href="#note327"><b>327)</b></a></sup> As the functions vfwprintf, vswprintf, vfwscanf, vwprintf, vwscanf, and vswscanf
invoke the va_arg macro, the value of arg after the return is indeterminate.
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+[<a name="
p414" href="#p414">page 414</a>] (<a href="#Contents">Contents</a>)
<a name="7.28.2.6" href="#7.28.2.6"><b> 7.28.2.6 The vfwscanf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
int vfwscanf(FILE * restrict stream,
const wchar_t * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vfwscanf function is equivalent to fwscanf, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vfwscanf function does not invoke the
va_end macro.327)
- Returns
+<b> Returns</b>
3 The vfwscanf function returns the value of the macro EOF if an input failure occurs
before the first conversion (if any) has completed. Otherwise, the vfwscanf function
returns the number of input items assigned, which can be fewer than provided for, or even
zero, in the event of an early matching failure.
<a name="7.28.2.7" href="#7.28.2.7"><b> 7.28.2.7 The vswprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.28"><wchar.h></a>
int vswprintf(wchar_t * restrict s,
size_t n,
const wchar_t * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vswprintf function is equivalent to swprintf, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vswprintf function does not invoke the
va_end macro.327)
- Returns
+<b> Returns</b>
3 The vswprintf function returns the number of wide characters written in the array, not
counting the terminating null wide character, or a negative value if an encoding error
occurred or if n or more wide characters were requested to be generated.
-
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+[<a name="p415" href="#p415">page 415</a>] (<a href="#Contents">Contents</a>)
<a name="7.28.2.8" href="#7.28.2.8"><b> 7.28.2.8 The vswscanf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.28"><wchar.h></a>
int vswscanf(const wchar_t * restrict s,
const wchar_t * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vswscanf function is equivalent to swscanf, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vswscanf function does not invoke the
va_end macro.327)
- Returns
+<b> Returns</b>
3 The vswscanf function returns the value of the macro EOF if an input failure occurs
before the first conversion (if any) has completed. Otherwise, the vswscanf function
returns the number of input items assigned, which can be fewer than provided for, or even
zero, in the event of an early matching failure.
<a name="7.28.2.9" href="#7.28.2.9"><b> 7.28.2.9 The vwprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.28"><wchar.h></a>
int vwprintf(const wchar_t * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vwprintf function is equivalent to wprintf, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vwprintf function does not invoke the
va_end macro.327)
- Returns
+<b> Returns</b>
3 The vwprintf function returns the number of wide characters transmitted, or a negative
value if an output or encoding error occurred.
-
-
-
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+[<a name="p416" href="#p416">page 416</a>] (<a href="#Contents">Contents</a>)
<a name="7.28.2.10" href="#7.28.2.10"><b> 7.28.2.10 The vwscanf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.28"><wchar.h></a>
int vwscanf(const wchar_t * restrict format,
va_list arg);
- Description
+<b> Description</b>
2 The vwscanf function is equivalent to wscanf, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vwscanf function does not invoke the
va_end macro.327)
- Returns
+<b> Returns</b>
3 The vwscanf function returns the value of the macro EOF if an input failure occurs
before the first conversion (if any) has completed. Otherwise, the vwscanf function
returns the number of input items assigned, which can be fewer than provided for, or even
zero, in the event of an early matching failure.
<a name="7.28.2.11" href="#7.28.2.11"><b> 7.28.2.11 The wprintf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
int wprintf(const wchar_t * restrict format, ...);
- Description
+<b> Description</b>
2 The wprintf function is equivalent to fwprintf with the argument stdout
interposed before the arguments to wprintf.
- Returns
+<b> Returns</b>
3 The wprintf function returns the number of wide characters transmitted, or a negative
value if an output or encoding error occurred.
<a name="7.28.2.12" href="#7.28.2.12"><b> 7.28.2.12 The wscanf function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
int wscanf(const wchar_t * restrict format, ...);
- Description
+<b> Description</b>
2 The wscanf function is equivalent to fwscanf with the argument stdin interposed
before the arguments to wscanf.
+[<a name="p417" href="#p417">page 417</a>] (<a href="#Contents">Contents</a>)
-[<a name="#p417" href="p417">page 417</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The wscanf function returns the value of the macro EOF if an input failure occurs
before the first conversion (if any) has completed. Otherwise, the wscanf function
returns the number of input items assigned, which can be fewer than provided for, or even
zero, in the event of an early matching failure.
<a name="7.28.3" href="#7.28.3"><b> 7.28.3 Wide character input/output functions</b></a>
<a name="7.28.3.1" href="#7.28.3.1"><b> 7.28.3.1 The fgetwc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
wint_t fgetwc(FILE *stream);
- Description
+<b> Description</b>
2 If the end-of-file indicator for the input stream pointed to by stream is not set and a
next wide character is present, the fgetwc function obtains that wide character as a
wchar_t converted to a wint_t and advances the associated file position indicator for
the stream (if defined).
- Returns
+<b> Returns</b>
3 If the end-of-file indicator for the stream is set, or if the stream is at end-of-file, the end-
of-file indicator for the stream is set and the fgetwc function returns WEOF. Otherwise,
the fgetwc function returns the next wide character from the input stream pointed to by
stream. If a read error occurs, the error indicator for the stream is set and the fgetwc
function returns WEOF. If an encoding error occurs (including too few bytes), the value of
- the macro EILSEQ is stored in errno and the fgetwc function returns WEOF.328)
+ the macro EILSEQ is stored in errno and the fgetwc function returns WEOF.<sup><a href="#note328"><b>328)</b></a></sup>
<a name="7.28.3.2" href="#7.28.3.2"><b> 7.28.3.2 The fgetws function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
wchar_t *fgetws(wchar_t * restrict s,
int n, FILE * restrict stream);
- Description
+<b> Description</b>
2 The fgetws function reads at most one less than the number of wide characters
specified by n from the stream pointed to by stream into the array pointed to by s. No
- 328) An end-of-file and a read error can be distinguished by use of the feof and ferror functions.
+ <sup><a name="note328" href="#note328"><b>328)</b></a></sup> An end-of-file and a read error can be distinguished by use of the feof and ferror functions.
Also, errno will be set to EILSEQ by input/output functions only if an encoding error occurs.
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additional wide characters are read after a new-line wide character (which is retained) or
after end-of-file. A null wide character is written immediately after the last wide
character read into the array.
- Returns
+<b> Returns</b>
3 The fgetws function returns s if successful. If end-of-file is encountered and no
characters have been read into the array, the contents of the array remain unchanged and a
null pointer is returned. If a read or encoding error occurs during the operation, the array
contents are indeterminate and a null pointer is returned.
<a name="7.28.3.3" href="#7.28.3.3"><b> 7.28.3.3 The fputwc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
wint_t fputwc(wchar_t c, FILE *stream);
- Description
+<b> Description</b>
2 The fputwc function writes the wide character specified by c to the output stream
pointed to by stream, at the position indicated by the associated file position indicator
for the stream (if defined), and advances the indicator appropriately. If the file cannot
support positioning requests, or if the stream was opened with append mode, the
character is appended to the output stream.
- Returns
+<b> Returns</b>
3 The fputwc function returns the wide character written. If a write error occurs, the
error indicator for the stream is set and fputwc returns WEOF. If an encoding error
occurs, the value of the macro EILSEQ is stored in errno and fputwc returns WEOF.
<a name="7.28.3.4" href="#7.28.3.4"><b> 7.28.3.4 The fputws function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
int fputws(const wchar_t * restrict s,
FILE * restrict stream);
- Description
+<b> Description</b>
2 The fputws function writes the wide string pointed to by s to the stream pointed to by
stream. The terminating null wide character is not written.
- Returns
+<b> Returns</b>
3 The fputws function returns EOF if a write or encoding error occurs; otherwise, it
returns a nonnegative value.
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#p419" href="p419">page 419</a>] (<a href="#Contents">Contents</a>)
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<a name="7.28.3.5" href="#7.28.3.5"><b> 7.28.3.5 The fwide function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
int fwide(FILE *stream, int mode);
- Description
+<b> Description</b>
2 The fwide function determines the orientation of the stream pointed to by stream. If
mode is greater than zero, the function first attempts to make the stream wide oriented. If
- mode is less than zero, the function first attempts to make the stream byte oriented.329)
+ mode is less than zero, the function first attempts to make the stream byte oriented.<sup><a href="#note329"><b>329)</b></a></sup>
Otherwise, mode is zero and the function does not alter the orientation of the stream.
- Returns
+<b> Returns</b>
3 The fwide function returns a value greater than zero if, after the call, the stream has
wide orientation, a value less than zero if the stream has byte orientation, or zero if the
stream has no orientation.
<a name="7.28.3.6" href="#7.28.3.6"><b> 7.28.3.6 The getwc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
wint_t getwc(FILE *stream);
- Description
+<b> Description</b>
2 The getwc function is equivalent to fgetwc, except that if it is implemented as a
macro, it may evaluate stream more than once, so the argument should never be an
expression with side effects.
- Returns
+<b> Returns</b>
3 The getwc function returns the next wide character from the input stream pointed to by
stream, or WEOF.
<a name="7.28.3.7" href="#7.28.3.7"><b> 7.28.3.7 The getwchar function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wint_t getwchar(void);
- 329) If the orientation of the stream has already been determined, fwide does not change it.
+ <sup><a name="note329" href="#note329"><b>329)</b></a></sup> If the orientation of the stream has already been determined, fwide does not change it.
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- Description
+<b> Description</b>
2 The getwchar function is equivalent to getwc with the argument stdin.
- Returns
+<b> Returns</b>
3 The getwchar function returns the next wide character from the input stream pointed to
by stdin, or WEOF.
<a name="7.28.3.8" href="#7.28.3.8"><b> 7.28.3.8 The putwc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
wint_t putwc(wchar_t c, FILE *stream);
- Description
+<b> Description</b>
2 The putwc function is equivalent to fputwc, except that if it is implemented as a
macro, it may evaluate stream more than once, so that argument should never be an
expression with side effects.
- Returns
+<b> Returns</b>
3 The putwc function returns the wide character written, or WEOF.
<a name="7.28.3.9" href="#7.28.3.9"><b> 7.28.3.9 The putwchar function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wint_t putwchar(wchar_t c);
- Description
+<b> Description</b>
2 The putwchar function is equivalent to putwc with the second argument stdout.
- Returns
+<b> Returns</b>
3 The putwchar function returns the character written, or WEOF.
<a name="7.28.3.10" href="#7.28.3.10"><b> 7.28.3.10 The ungetwc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
wint_t ungetwc(wint_t c, FILE *stream);
- Description
+<b> Description</b>
2 The ungetwc function pushes the wide character specified by c back onto the input
stream pointed to by stream. Pushed-back wide characters will be returned by
subsequent reads on that stream in the reverse order of their pushing. A successful
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intervening call (with the stream pointed to by stream) to a file positioning function
(fseek, fsetpos, or rewind) discards any pushed-back wide characters for the
back. For a text or binary stream, the value of its file position indicator after a successful
call to the ungetwc function is unspecified until all pushed-back wide characters are
read or discarded.
- Returns
+<b> Returns</b>
6 The ungetwc function returns the wide character pushed back, or WEOF if the operation
fails.
<a name="7.28.4" href="#7.28.4"><b> 7.28.4 General wide string utilities</b></a>
wide character sequences returns zero, and a function that copies wide characters copies
zero wide characters.
-
-
-
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<a name="7.28.4.1" href="#7.28.4.1"><b> 7.28.4.1 Wide string numeric conversion functions</b></a>
<a name="7.28.4.1.1" href="#7.28.4.1.1"><b> 7.28.4.1.1 The wcstod, wcstof, and wcstold functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
double wcstod(const wchar_t * restrict nptr,
wchar_t ** restrict endptr);
wchar_t ** restrict endptr);
long double wcstold(const wchar_t * restrict nptr,
wchar_t ** restrict endptr);
- Description
+<b> Description</b>
2 The wcstod, wcstof, and wcstold functions convert the initial portion of the wide
string pointed to by nptr to double, float, and long double representation,
respectively. First, they decompose the input string into three parts: an initial, possibly
n-wchar-sequence nondigit
The subject sequence is defined as the longest initial subsequence of the input wide
string, starting with the first non-white-space wide character, that is of the expected form.
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+
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The subject sequence contains no wide characters if the input wide string is not of the
expected form.
floating point number, or if a binary exponent part does not appear in a hexadecimal
floating point number, an exponent part of the appropriate type with value zero is
assumed to follow the last digit in the string. If the subject sequence begins with a minus
- sign, the sequence is interpreted as negated.330) A wide character sequence INF or
+ sign, the sequence is interpreted as negated.<sup><a href="#note330"><b>330)</b></a></sup> A wide character sequence INF or
INFINITY is interpreted as an infinity, if representable in the return type, else like a
floating constant that is too large for the range of the return type. A wide character
sequence NAN or NAN(n-wchar-sequenceopt) is interpreted as a quiet NaN, if supported
in the return type, else like a subject sequence part that does not have the expected form;
- the meaning of the n-wchar sequences is implementation-defined.331) A pointer to the
+ the meaning of the n-wchar sequences is implementation-defined.<sup><a href="#note331"><b>331)</b></a></sup> A pointer to the
final wide string is stored in the object pointed to by endptr, provided that endptr is
not a null pointer.
5 If the subject sequence has the hexadecimal form and FLT_RADIX is a power of 2, the
- 330) It is unspecified whether a minus-signed sequence is converted to a negative number directly or by
+ <sup><a name="note330" href="#note330"><b>330)</b></a></sup> It is unspecified whether a minus-signed sequence is converted to a negative number directly or by
negating the value resulting from converting the corresponding unsigned sequence (see <a href="#F.5">F.5</a>); the two
methods may yield different results if rounding is toward positive or negative infinity. In either case,
the functions honor the sign of zero if floating-point arithmetic supports signed zeros.
- 331) An implementation may use the n-wchar sequence to determine extra information to be represented in
+ <sup><a name="note331" href="#note331"><b>331)</b></a></sup> An implementation may use the n-wchar sequence to determine extra information to be represented in
the NaN's significand.
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9 If the subject sequence has the decimal form and at most DECIMAL_DIG (defined in
<a href="#7.7"><float.h></a>) significant digits, the result should be correctly rounded. If the subject
The result should be one of the (equal or adjacent) values that would be obtained by
correctly rounding L and U according to the current rounding direction, with the extra
stipulation that the error with respect to D should have a correct sign for the current
- rounding direction.332)
- Returns
+ rounding direction.<sup><a href="#note332"><b>332)</b></a></sup>
+<b> Returns</b>
10 The functions return the converted value, if any. If no conversion could be performed,
zero is returned. If the correct value overflows and default rounding is in effect (<a href="#7.12.1">7.12.1</a>),
plus or minus HUGE_VAL, HUGE_VALF, or HUGE_VALL is returned (according to the
-
332) DECIMAL_DIG, defined in <a href="#7.7"><float.h></a>, should be sufficiently large that L and U will usually round
+
<sup><a name="note332" href="#note332"><b>332)</b></a></sup> DECIMAL_DIG, defined in <a href="#7.7"><float.h></a>, should be sufficiently large that L and U will usually round
to the same internal floating value, but if not will round to adjacent values.
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<a name="7.28.4.1.2" href="#7.28.4.1.2"><b> 7.28.4.1.2 The wcstol, wcstoll, wcstoul, and wcstoull functions</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
long int wcstol(
const wchar_t * restrict nptr,
const wchar_t * restrict nptr,
wchar_t ** restrict endptr,
int base);
- Description
+<b> Description</b>
2 The wcstol, wcstoll, wcstoul, and wcstoull functions convert the initial
portion of the wide string pointed to by nptr to long int, long long int,
unsigned long int, and unsigned long long int representation,
value of base is 16, the wide characters 0x or 0X may optionally precede the sequence
of letters and digits, following the sign if present.
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4 The subject sequence is defined as the longest initial subsequence of the input wide
string, starting with the first non-white-space wide character, that is of the expected form.
7 If the subject sequence is empty or does not have the expected form, no conversion is
performed; the value of nptr is stored in the object pointed to by endptr, provided
that endptr is not a null pointer.
- Returns
+<b> Returns</b>
8 The wcstol, wcstoll, wcstoul, and wcstoull functions return the converted
value, if any. If no conversion could be performed, zero is returned. If the correct value
is outside the range of representable values, LONG_MIN, LONG_MAX, LLONG_MIN,
sign of the value, if any), and the value of the macro ERANGE is stored in errno.
<a name="7.28.4.2" href="#7.28.4.2"><b> 7.28.4.2 Wide string copying functions</b></a>
<a name="7.28.4.2.1" href="#7.28.4.2.1"><b> 7.28.4.2.1 The wcscpy function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wcscpy(wchar_t * restrict s1,
const wchar_t * restrict s2);
- Description
+<b> Description</b>
2 The wcscpy function copies the wide string pointed to by s2 (including the terminating
null wide character) into the array pointed to by s1.
- Returns
+<b> Returns</b>
3 The wcscpy function returns the value of s1.
-
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<a name="7.28.4.2.2" href="#7.28.4.2.2"><b> 7.28.4.2.2 The wcsncpy function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wcsncpy(wchar_t * restrict s1,
const wchar_t * restrict s2,
size_t n);
- Description
+<b> Description</b>
2 The wcsncpy function copies not more than n wide characters (those that follow a null
wide character are not copied) from the array pointed to by s2 to the array pointed to by
- s1.333)
+ s1.<sup><a href="#note333"><b>333)</b></a></sup>
3 If the array pointed to by s2 is a wide string that is shorter than n wide characters, null
wide characters are appended to the copy in the array pointed to by s1, until n wide
characters in all have been written.
- Returns
+<b> Returns</b>
4 The wcsncpy function returns the value of s1.
<a name="7.28.4.2.3" href="#7.28.4.2.3"><b> 7.28.4.2.3 The wmemcpy function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wmemcpy(wchar_t * restrict s1,
const wchar_t * restrict s2,
size_t n);
- Description
+<b> Description</b>
2 The wmemcpy function copies n wide characters from the object pointed to by s2 to the
object pointed to by s1.
- Returns
+<b> Returns</b>
3 The wmemcpy function returns the value of s1.
- 333) Thus, if there is no null wide character in the first n wide characters of the array pointed to by s2, the
+ <sup><a name="note333" href="#note333"><b>333)</b></a></sup> Thus, if there is no null wide character in the first n wide characters of the array pointed to by s2, the
result will not be null-terminated.
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+[<a name="
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<a name="7.28.4.2.4" href="#7.28.4.2.4"><b> 7.28.4.2.4 The wmemmove function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wmemmove(wchar_t *s1, const wchar_t *s2,
size_t n);
- Description
+<b> Description</b>
2 The wmemmove function copies n wide characters from the object pointed to by s2 to
the object pointed to by s1. Copying takes place as if the n wide characters from the
object pointed to by s2 are first copied into a temporary array of n wide characters that
does not overlap the objects pointed to by s1 or s2, and then the n wide characters from
the temporary array are copied into the object pointed to by s1.
- Returns
+<b> Returns</b>
3 The wmemmove function returns the value of s1.
<a name="7.28.4.3" href="#7.28.4.3"><b> 7.28.4.3 Wide string concatenation functions</b></a>
<a name="7.28.4.3.1" href="#7.28.4.3.1"><b> 7.28.4.3.1 The wcscat function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wcscat(wchar_t * restrict s1,
const wchar_t * restrict s2);
- Description
+<b> Description</b>
2 The wcscat function appends a copy of the wide string pointed to by s2 (including the
terminating null wide character) to the end of the wide string pointed to by s1. The initial
wide character of s2 overwrites the null wide character at the end of s1.
- Returns
+<b> Returns</b>
3 The wcscat function returns the value of s1.
<a name="7.28.4.3.2" href="#7.28.4.3.2"><b> 7.28.4.3.2 The wcsncat function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wcsncat(wchar_t * restrict s1,
const wchar_t * restrict s2,
size_t n);
- Description
+<b> Description</b>
2 The wcsncat function appends not more than n wide characters (a null wide character
and those that follow it are not appended) from the array pointed to by s2 to the end of
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the wide string pointed to by s1. The initial wide character of s2 overwrites the null
wide character at the end of s1. A terminating null wide character is always appended to
- the result.334)
- Returns
+ the result.<sup><a href="#note334"><b>334)</b></a></sup>
+<b> Returns</b>
3 The wcsncat function returns the value of s1.
<a name="7.28.4.4" href="#7.28.4.4"><b> 7.28.4.4 Wide string comparison functions</b></a>
1 Unless explicitly stated otherwise, the functions described in this subclause order two
wide characters the same way as two integers of the underlying integer type designated
by wchar_t.
<a name="7.28.4.4.1" href="#7.28.4.4.1"><b> 7.28.4.4.1 The wcscmp function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
int wcscmp(const wchar_t *s1, const wchar_t *s2);
- Description
+<b> Description</b>
2 The wcscmp function compares the wide string pointed to by s1 to the wide string
pointed to by s2.
- Returns
+<b> Returns</b>
3 The wcscmp function returns an integer greater than, equal to, or less than zero,
accordingly as the wide string pointed to by s1 is greater than, equal to, or less than the
wide string pointed to by s2.
<a name="7.28.4.4.2" href="#7.28.4.4.2"><b> 7.28.4.4.2 The wcscoll function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
int wcscoll(const wchar_t *s1, const wchar_t *s2);
- Description
+<b> Description</b>
2 The wcscoll function compares the wide string pointed to by s1 to the wide string
pointed to by s2, both interpreted as appropriate to the LC_COLLATE category of the
current locale.
- Returns
+<b> Returns</b>
3 The wcscoll function returns an integer greater than, equal to, or less than zero,
accordingly as the wide string pointed to by s1 is greater than, equal to, or less than the
- 334) Thus, the maximum number of wide characters that can end up in the array pointed to by s1 is
+ <sup><a name="note334" href="#note334"><b>334)</b></a></sup> Thus, the maximum number of wide characters that can end up in the array pointed to by s1 is
wcslen(s1)+n+1.
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wide string pointed to by s2 when both are interpreted as appropriate to the current
locale.
<a name="7.28.4.4.3" href="#7.28.4.4.3"><b> 7.28.4.4.3 The wcsncmp function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
int wcsncmp(const wchar_t *s1, const wchar_t *s2,
size_t n);
- Description
+<b> Description</b>
2 The wcsncmp function compares not more than n wide characters (those that follow a
null wide character are not compared) from the array pointed to by s1 to the array
pointed to by s2.
- Returns
+<b> Returns</b>
3 The wcsncmp function returns an integer greater than, equal to, or less than zero,
accordingly as the possibly null-terminated array pointed to by s1 is greater than, equal
to, or less than the possibly null-terminated array pointed to by s2.
<a name="7.28.4.4.4" href="#7.28.4.4.4"><b> 7.28.4.4.4 The wcsxfrm function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
size_t wcsxfrm(wchar_t * restrict s1,
const wchar_t * restrict s2,
size_t n);
- Description
+<b> Description</b>
2 The wcsxfrm function transforms the wide string pointed to by s2 and places the
resulting wide string into the array pointed to by s1. The transformation is such that if
the wcscmp function is applied to two transformed wide strings, it returns a value greater
applied to the same two original wide strings. No more than n wide characters are placed
into the resulting array pointed to by s1, including the terminating null wide character. If
n is zero, s1 is permitted to be a null pointer.
- Returns
+<b> Returns</b>
3 The wcsxfrm function returns the length of the transformed wide string (not including
the terminating null wide character). If the value returned is n or greater, the contents of
the array pointed to by s1 are indeterminate.
4 EXAMPLE The value of the following expression is the length of the array needed to hold the
transformation of the wide string pointed to by s:
-
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1 + wcsxfrm(NULL, s, 0)
<a name="7.28.4.4.5" href="#7.28.4.4.5"><b> 7.28.4.4.5 The wmemcmp function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
int wmemcmp(const wchar_t *s1, const wchar_t *s2,
size_t n);
- Description
+<b> Description</b>
2 The wmemcmp function compares the first n wide characters of the object pointed to by
s1 to the first n wide characters of the object pointed to by s2.
- Returns
+<b> Returns</b>
3 The wmemcmp function returns an integer greater than, equal to, or less than zero,
accordingly as the object pointed to by s1 is greater than, equal to, or less than the object
pointed to by s2.
<a name="7.28.4.5" href="#7.28.4.5"><b> 7.28.4.5 Wide string search functions</b></a>
<a name="7.28.4.5.1" href="#7.28.4.5.1"><b> 7.28.4.5.1 The wcschr function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wcschr(const wchar_t *s, wchar_t c);
- Description
+<b> Description</b>
2 The wcschr function locates the first occurrence of c in the wide string pointed to by s.
The terminating null wide character is considered to be part of the wide string.
- Returns
+<b> Returns</b>
3 The wcschr function returns a pointer to the located wide character, or a null pointer if
the wide character does not occur in the wide string.
<a name="7.28.4.5.2" href="#7.28.4.5.2"><b> 7.28.4.5.2 The wcscspn function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
size_t wcscspn(const wchar_t *s1, const wchar_t *s2);
- Description
+<b> Description</b>
2 The wcscspn function computes the length of the maximum initial segment of the wide
string pointed to by s1 which consists entirely of wide characters not from the wide
string pointed to by s2.
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-
-[<a name="#p432" href="p432">page 432</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The wcscspn function returns the length of the segment.
<a name="7.28.4.5.3" href="#7.28.4.5.3"><b> 7.28.4.5.3 The wcspbrk function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wcspbrk(const wchar_t *s1, const wchar_t *s2);
- Description
+<b> Description</b>
2 The wcspbrk function locates the first occurrence in the wide string pointed to by s1 of
any wide character from the wide string pointed to by s2.
- Returns
+<b> Returns</b>
3 The wcspbrk function returns a pointer to the wide character in s1, or a null pointer if
no wide character from s2 occurs in s1.
<a name="7.28.4.5.4" href="#7.28.4.5.4"><b> 7.28.4.5.4 The wcsrchr function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wcsrchr(const wchar_t *s, wchar_t c);
- Description
+<b> Description</b>
2 The wcsrchr function locates the last occurrence of c in the wide string pointed to by
s. The terminating null wide character is considered to be part of the wide string.
- Returns
+<b> Returns</b>
3 The wcsrchr function returns a pointer to the wide character, or a null pointer if c does
not occur in the wide string.
<a name="7.28.4.5.5" href="#7.28.4.5.5"><b> 7.28.4.5.5 The wcsspn function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
size_t wcsspn(const wchar_t *s1, const wchar_t *s2);
- Description
+<b> Description</b>
2 The wcsspn function computes the length of the maximum initial segment of the wide
string pointed to by s1 which consists entirely of wide characters from the wide string
pointed to by s2.
- Returns
+<b> Returns</b>
3 The wcsspn function returns the length of the segment.
-
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<a name="7.28.4.5.6" href="#7.28.4.5.6"><b> 7.28.4.5.6 The wcsstr function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wcsstr(const wchar_t *s1, const wchar_t *s2);
- Description
+<b> Description</b>
2 The wcsstr function locates the first occurrence in the wide string pointed to by s1 of
the sequence of wide characters (excluding the terminating null wide character) in the
wide string pointed to by s2.
- Returns
+<b> Returns</b>
3 The wcsstr function returns a pointer to the located wide string, or a null pointer if the
wide string is not found. If s2 points to a wide string with zero length, the function
returns s1.
<a name="7.28.4.5.7" href="#7.28.4.5.7"><b> 7.28.4.5.7 The wcstok function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wcstok(wchar_t * restrict s1,
const wchar_t * restrict s2,
wchar_t ** restrict ptr);
- Description
+<b> Description</b>
2 A sequence of calls to the wcstok function breaks the wide string pointed to by s1 into
a sequence of tokens, each of which is delimited by a wide character from the wide string
pointed to by s2. The third argument points to a caller-provided wchar_t pointer into
the start of the first token.
5 The wcstok function then searches from there for a wide character that is contained in
the current separator wide string. If no such wide character is found, the current token
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+
+[<a name="p434" href="#p434">page 434</a>] (<a href="#Contents">Contents</a>)
extends to the end of the wide string pointed to by s1, and subsequent searches in the
same wide string for a token return a null pointer. If such a wide character is found, it is
by ptr so that subsequent calls, with a null pointer for s1 and the unmodified pointer
value for ptr, shall start searching just past the element overwritten by a null wide
character (if any).
- Returns
+<b> Returns</b>
7 The wcstok function returns a pointer to the first wide character of a token, or a null
pointer if there is no token.
8 EXAMPLE
t = wcstok(NULL, L"?", &ptr1); // t is a null pointer
<a name="7.28.4.5.8" href="#7.28.4.5.8"><b> 7.28.4.5.8 The wmemchr function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wmemchr(const wchar_t *s, wchar_t c,
size_t n);
- Description
+<b> Description</b>
2 The wmemchr function locates the first occurrence of c in the initial n wide characters of
the object pointed to by s.
- Returns
+<b> Returns</b>
3 The wmemchr function returns a pointer to the located wide character, or a null pointer if
the wide character does not occur in the object.
-
-
-
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+[<a name="p435" href="#p435">page 435</a>] (<a href="#Contents">Contents</a>)
<a name="7.28.4.6" href="#7.28.4.6"><b> 7.28.4.6 Miscellaneous functions</b></a>
<a name="7.28.4.6.1" href="#7.28.4.6.1"><b> 7.28.4.6.1 The wcslen function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
size_t wcslen(const wchar_t *s);
- Description
+<b> Description</b>
2 The wcslen function computes the length of the wide string pointed to by s.
- Returns
+<b> Returns</b>
3 The wcslen function returns the number of wide characters that precede the terminating
null wide character.
<a name="7.28.4.6.2" href="#7.28.4.6.2"><b> 7.28.4.6.2 The wmemset function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
wchar_t *wmemset(wchar_t *s, wchar_t c, size_t n);
- Description
+<b> Description</b>
2 The wmemset function copies the value of c into each of the first n wide characters of
the object pointed to by s.
- Returns
+<b> Returns</b>
3 The wmemset function returns the value of s.
<a name="7.28.5" href="#7.28.5"><b> 7.28.5 Wide character time conversion functions</b></a>
<a name="7.28.5.1" href="#7.28.5.1"><b> 7.28.5.1 The wcsftime function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.26"><time.h></a>
#include <a href="#7.28"><wchar.h></a>
size_t wcsftime(wchar_t * restrict s,
size_t maxsize,
const wchar_t * restrict format,
const struct tm * restrict timeptr);
- Description
+<b> Description</b>
2 The wcsftime function is equivalent to the strftime function, except that:
-- The argument s points to the initial element of an array of wide characters into which
the generated output is to be placed.
-
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+[<a name="p436" href="#p436">page 436</a>] (<a href="#Contents">Contents</a>)
-- The argument maxsize indicates the limiting number of wide characters.
-- The argument format is a wide string and the conversion specifiers are replaced by
corresponding sequences of wide characters.
-- The return value indicates the number of wide characters.
- Returns
+<b> Returns</b>
3 If the total number of resulting wide characters including the terminating null wide
character is not more than maxsize, the wcsftime function returns the number of
wide characters placed into the array pointed to by s not including the terminating null
been altered by any of the functions described in this subclause, and is then used with a
different multibyte character sequence, or in the other conversion direction, or with a
different LC_CTYPE category setting than on earlier function calls, the behavior is
- undefined.335)
+ undefined.<sup><a href="#note335"><b>335)</b></a></sup>
4 On entry, each function takes the described conversion state (either internal or pointed to
by an argument) as current. The conversion state described by the referenced object is
altered as needed to track the shift state, and the position within a multibyte character, for
- 335) Thus, a particular mbstate_t object can be used, for example, with both the mbrtowc and
+ <sup><a name="note335" href="#note335"><b>335)</b></a></sup> Thus, a particular mbstate_t object can be used, for example, with both the mbrtowc and
mbsrtowcs functions as long as they are used to step sequentially through the same multibyte
character string.
-[<a name="
#p437" href="p437">page 437</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p437" href="#p437">page 437</a>] (<a href="#Contents">Contents</a>)
<a name="7.28.6.1" href="#7.28.6.1"><b> 7.28.6.1 Single-byte/wide character conversion functions</b></a>
<a name="7.28.6.1.1" href="#7.28.6.1.1"><b> 7.28.6.1.1 The btowc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a> *
wint_t btowc(int c);
- Description
+<b> Description</b>
2 The btowc function determines whether c constitutes a valid single-byte character in the
initial shift state.
- Returns
+<b> Returns</b>
3 The btowc function returns WEOF if c has the value EOF or if (unsigned char)c
does not constitute a valid single-byte character in the initial shift state. Otherwise, it
returns the wide character representation of that character.
<a name="7.28.6.1.2" href="#7.28.6.1.2"><b> 7.28.6.1.2 The wctob function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a> *
int wctob(wint_t c);
- Description
+<b> Description</b>
2 The wctob function determines whether c corresponds to a member of the extended
character set whose multibyte character representation is a single byte when in the initial
shift state.
- Returns
+<b> Returns</b>
3 The wctob function returns EOF if c does not correspond to a multibyte character with
length one in the initial shift state. Otherwise, it returns the single-byte representation of
that character as an unsigned char converted to an int.
<a name="7.28.6.2" href="#7.28.6.2"><b> 7.28.6.2 Conversion state functions</b></a>
<a name="7.28.6.2.1" href="#7.28.6.2.1"><b> 7.28.6.2.1 The mbsinit function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
int mbsinit(const mbstate_t *ps);
- Description
+<b> Description</b>
2 If ps is not a null pointer, the mbsinit function determines whether the referenced
mbstate_t object describes an initial conversion state.
+[<a name="p438" href="#p438">page 438</a>] (<a href="#Contents">Contents</a>)
-
-[<a name="#p438" href="p438">page 438</a>] (<a href="#Contents">Contents</a>)
-
- Returns
+<b> Returns</b>
3 The mbsinit function returns nonzero if ps is a null pointer or if the referenced object
describes an initial conversion state; otherwise, it returns zero.
<a name="7.28.6.3" href="#7.28.6.3"><b> 7.28.6.3 Restartable multibyte/wide character conversion functions</b></a>
2 Also unlike their corresponding functions, the return value does not represent whether the
encoding is state-dependent.
<a name="7.28.6.3.1" href="#7.28.6.3.1"><b> 7.28.6.3.1 The mbrlen function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
size_t mbrlen(const char * restrict s,
size_t n,
mbstate_t * restrict ps);
- Description
+<b> Description</b>
2 The mbrlen function is equivalent to the call:
mbrtowc(NULL, s, n, ps != NULL ? ps : &internal)
where internal is the mbstate_t object for the mbrlen function, except that the
expression designated by ps is evaluated only once.
- Returns
+<b> Returns</b>
3 The mbrlen function returns a value between zero and n, inclusive, (size_t)(-2),
or (size_t)(-1).
Forward references: the mbrtowc function (<a href="#7.28.6.3.2">7.28.6.3.2</a>).
-
-
-
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+[<a name="p439" href="#p439">page 439</a>] (<a href="#Contents">Contents</a>)
<a name="7.28.6.3.2" href="#7.28.6.3.2"><b> 7.28.6.3.2 The mbrtowc function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
size_t mbrtowc(wchar_t * restrict pwc,
const char * restrict s,
size_t n,
mbstate_t * restrict ps);
- Description
+<b> Description</b>
2 If s is a null pointer, the mbrtowc function is equivalent to the call:
mbrtowc(NULL, "", 1, ps)
In this case, the values of the parameters pwc and n are ignored.
corresponding wide character and then, if pwc is not a null pointer, stores that value in
the object pointed to by pwc. If the corresponding wide character is the null wide
character, the resulting state described is the initial conversion state.
- Returns
+<b> Returns</b>
4 The mbrtowc function returns the first of the following that applies (given the current
conversion state):
0 if the next n or fewer bytes complete the multibyte character that
of bytes that complete the multibyte character.
(size_t)(-2) if the next n bytes contribute to an incomplete (but potentially valid)
multibyte character, and all n bytes have been processed (no value is
- stored).336)
+ stored).<sup><a href="#note336"><b>336)</b></a></sup>
(size_t)(-1) if an encoding error occurs, in which case the next n or fewer bytes
do not contribute to a complete and valid multibyte character (no
value is stored); the value of the macro EILSEQ is stored in errno,
and the conversion state is unspecified.
- 336) When n has at least the value of the MB_CUR_MAX macro, this case can only occur if s points at a
+ <sup><a name="note336" href="#note336"><b>336)</b></a></sup> When n has at least the value of the MB_CUR_MAX macro, this case can only occur if s points at a
sequence of redundant shift sequences (for implementations with state-dependent encodings).
-[<a name="
#p440" href="p440">page 440</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p440" href="#p440">page 440</a>] (<a href="#Contents">Contents</a>)
<a name="7.28.6.3.3" href="#7.28.6.3.3"><b> 7.28.6.3.3 The wcrtomb function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
size_t wcrtomb(char * restrict s,
wchar_t wc,
mbstate_t * restrict ps);
- Description
+<b> Description</b>
2 If s is a null pointer, the wcrtomb function is equivalent to the call
wcrtomb(buf, L'\0', ps)
where buf is an internal buffer.
array whose first element is pointed to by s. At most MB_CUR_MAX bytes are stored. If
wc is a null wide character, a null byte is stored, preceded by any shift sequence needed
to restore the initial shift state; the resulting state described is the initial conversion state.
- Returns
+<b> Returns</b>
4 The wcrtomb function returns the number of bytes stored in the array object (including
any shift sequences). When wc is not a valid wide character, an encoding error occurs:
the function stores the value of the macro EILSEQ in errno and returns
when dst is not a null pointer), the pointer object pointed to by this parameter is updated
to reflect the amount of the source processed by that invocation.
-
-
-
-[<a name="#p441" href="p441">page 441</a>] (<a href="#Contents">Contents</a>)
+[<a name="p441" href="#p441">page 441</a>] (<a href="#Contents">Contents</a>)
<a name="7.28.6.4.1" href="#7.28.6.4.1"><b> 7.28.6.4.1 The mbsrtowcs function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
size_t mbsrtowcs(wchar_t * restrict dst,
const char ** restrict src,
size_t len,
mbstate_t * restrict ps);
- Description
+<b> Description</b>
2 The mbsrtowcs function converts a sequence of multibyte characters that begins in the
conversion state described by the object pointed to by ps, from the array indirectly
pointed to by src into a sequence of corresponding wide characters. If dst is not a null
continues up to and including a terminating null character, which is also stored.
Conversion stops earlier in two cases: when a sequence of bytes is encountered that does
not form a valid multibyte character, or (if dst is not a null pointer) when len wide
- characters have been stored into the array pointed to by dst.337) Each conversion takes
+ characters have been stored into the array pointed to by dst.<sup><a href="#note337"><b>337)</b></a></sup> Each conversion takes
place as if by a call to the mbrtowc function.
3 If dst is not a null pointer, the pointer object pointed to by src is assigned either a null
pointer (if conversion stopped due to reaching a terminating null character) or the address
just past the last multibyte character converted (if any). If conversion stopped due to
reaching a terminating null character and if dst is not a null pointer, the resulting state
described is the initial conversion state.
- Returns
+<b> Returns</b>
4 If the input conversion encounters a sequence of bytes that do not form a valid multibyte
character, an encoding error occurs: the mbsrtowcs function stores the value of the
macro EILSEQ in errno and returns (size_t)(-1); the conversion state is
- 337) Thus, the value of len is ignored if dst is a null pointer.
+ <sup><a name="note337" href="#note337"><b>337)</b></a></sup> Thus, the value of len is ignored if dst is a null pointer.
-[<a name="
#p442" href="p442">page 442</a>] (<a href="#Contents">Contents</a>)
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p442" href="#p442">page 442</a>] (<a href="#Contents">Contents</a>)
<a name="7.28.6.4.2" href="#7.28.6.4.2"><b> 7.28.6.4.2 The wcsrtombs function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.28"><wchar.h></a>
size_t wcsrtombs(char * restrict dst,
const wchar_t ** restrict src,
size_t len,
mbstate_t * restrict ps);
- Description
+<b> Description</b>
2 The wcsrtombs function converts a sequence of wide characters from the array
indirectly pointed to by src into a sequence of corresponding multibyte characters that
begins in the conversion state described by the object pointed to by ps. If dst is not a
not correspond to a valid multibyte character, or (if dst is not a null pointer) when the
next multibyte character would exceed the limit of len total bytes to be stored into the
array pointed to by dst. Each conversion takes place as if by a call to the wcrtomb
- function.338)
+ function.<sup><a href="#note338"><b>338)</b></a></sup>
3 If dst is not a null pointer, the pointer object pointed to by src is assigned either a null
pointer (if conversion stopped due to reaching a terminating null wide character) or the
address just past the last wide character converted (if any). If conversion stopped due to
reaching a terminating null wide character, the resulting state described is the initial
conversion state.
- Returns
+<b> Returns</b>
4 If conversion stops because a wide character is reached that does not correspond to a
valid multibyte character, an encoding error occurs: the wcsrtombs function stores the
value of the macro EILSEQ in errno and returns (size_t)(-1); the conversion
- 338) If conversion stops because a terminating null wide character has been reached, the bytes stored
+ <sup><a name="note338" href="#note338"><b>338)</b></a></sup> If conversion stops because a terminating null wide character has been reached, the bytes stored
include those necessary to reach the initial shift state immediately before the null byte.
-[<a name="
#p443" href="p443">page 443</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p443" href="#p443">page 443</a>] (<a href="#Contents">Contents</a>)
<a name="7.29" href="#7.29"><b> 7.29 Wide character classification and mapping utilities <wctype.h></b></a>
<a name="7.29.1" href="#7.29.1"><b> 7.29.1 Introduction</b></a>
1 The header <a href="#7.29"><wctype.h></a> defines one macro, and declares three data types and many
- functions.339)
+ functions.<sup><a href="#note339"><b>339)</b></a></sup>
2 The types declared are
wint_t
described in <a href="#7.28.1">7.28.1</a>;
-
339) See ''future library directions'' (<a href="#7.30.13">7.30.13</a>).
+
<sup><a name="note339" href="#note339"><b>339)</b></a></sup> See ''future library directions'' (<a href="#7.30.13">7.30.13</a>).
-[<a name="
#p444" href="p444">page 444</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p444" href="#p444">page 444</a>] (<a href="#Contents">Contents</a>)
<a name="7.29.2" href="#7.29.2"><b> 7.29.2 Wide character classification utilities</b></a>
1 The header <a href="#7.29"><wctype.h></a> declares several functions useful for classifying wide
if by a call to the wctob function) to a single-byte character for which the corresponding
character classification function from <a href="#7.4.1">7.4.1</a> returns true, except that the iswgraph and
iswpunct functions may differ with respect to wide characters other than L' ' that are
- both printing and white-space wide characters.340)
+ both printing and white-space wide characters.<sup><a href="#note340"><b>340)</b></a></sup>
Forward references: the wctob function (<a href="#7.28.6.1.2">7.28.6.1.2</a>).
<a name="7.29.2.1.1" href="#7.29.2.1.1"><b> 7.29.2.1.1 The iswalnum function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswalnum(wint_t wc);
- Description
+<b> Description</b>
2 The iswalnum function tests for any wide character for which iswalpha or
iswdigit is true.
<a name="7.29.2.1.2" href="#7.29.2.1.2"><b> 7.29.2.1.2 The iswalpha function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswalpha(wint_t wc);
- Description
+<b> Description</b>
2 The iswalpha function tests for any wide character for which iswupper or
iswlower is true, or any wide character that is one of a locale-specific set of alphabetic
- 340) For example, if the expression isalpha(wctob(wc)) evaluates to true, then the call
+ <sup><a name="note340" href="#note340"><b>340)</b></a></sup> For example, if the expression isalpha(wctob(wc)) evaluates to true, then the call
iswalpha(wc) also returns true. But, if the expression isgraph(wctob(wc)) evaluates to true
(which cannot occur for wc == L' ' of course), then either iswgraph(wc) or iswprint(wc)
&& iswspace(wc) is true, but not both.
-[<a name="
#p445" href="p445">page 445</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p445" href="#p445">page 445</a>] (<a href="#Contents">Contents</a>)
wide characters for which none of iswcntrl, iswdigit, iswpunct, or iswspace
- is true.341)
+ is true.<sup><a href="#note341"><b>341)</b></a></sup>
<a name="7.29.2.1.3" href="#7.29.2.1.3"><b> 7.29.2.1.3 The iswblank function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswblank(wint_t wc);
- Description
+<b> Description</b>
2 The iswblank function tests for any wide character that is a standard blank wide
character or is one of a locale-specific set of wide characters for which iswspace is true
and that is used to separate words within a line of text. The standard blank wide
characters are the following: space (L' '), and horizontal tab (L'\t'). In the "C"
locale, iswblank returns true only for the standard blank characters.
<a name="7.29.2.1.4" href="#7.29.2.1.4"><b> 7.29.2.1.4 The iswcntrl function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswcntrl(wint_t wc);
- Description
+<b> Description</b>
2 The iswcntrl function tests for any control wide character.
<a name="7.29.2.1.5" href="#7.29.2.1.5"><b> 7.29.2.1.5 The iswdigit function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswdigit(wint_t wc);
- Description
+<b> Description</b>
2 The iswdigit function tests for any wide character that corresponds to a decimal-digit
character (as defined in <a href="#5.2.1">5.2.1</a>).
<a name="7.29.2.1.6" href="#7.29.2.1.6"><b> 7.29.2.1.6 The iswgraph function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswgraph(wint_t wc);
- 341) The functions iswlower and iswupper test true or false separately for each of these additional
+ <sup><a name="note341" href="#note341"><b>341)</b></a></sup> The functions iswlower and iswupper test true or false separately for each of these additional
wide characters; all four combinations are possible.
-[<a name="
#p446" href="p446">page 446</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p446" href="#p446">page 446</a>] (<a href="#Contents">Contents</a>)
- Description
+<b> Description</b>
2 The iswgraph function tests for any wide character for which iswprint is true and
- iswspace is false.342)
+ iswspace is false.<sup><a href="#note342"><b>342)</b></a></sup>
<a name="7.29.2.1.7" href="#7.29.2.1.7"><b> 7.29.2.1.7 The iswlower function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswlower(wint_t wc);
- Description
+<b> Description</b>
2 The iswlower function tests for any wide character that corresponds to a lowercase
letter or is one of a locale-specific set of wide characters for which none of iswcntrl,
iswdigit, iswpunct, or iswspace is true.
<a name="7.29.2.1.8" href="#7.29.2.1.8"><b> 7.29.2.1.8 The iswprint function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswprint(wint_t wc);
- Description
+<b> Description</b>
2 The iswprint function tests for any printing wide character.
<a name="7.29.2.1.9" href="#7.29.2.1.9"><b> 7.29.2.1.9 The iswpunct function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswpunct(wint_t wc);
- Description
+<b> Description</b>
2 The iswpunct function tests for any printing wide character that is one of a locale-
specific set of punctuation wide characters for which neither iswspace nor iswalnum
is true.342)
<a name="7.29.2.1.10" href="#7.29.2.1.10"><b> 7.29.2.1.10 The iswspace function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswspace(wint_t wc);
- 342) Note that the behavior of the iswgraph and iswpunct functions may differ from their
+ <sup><a name="note342" href="#note342"><b>342)</b></a></sup> Note that the behavior of the iswgraph and iswpunct functions may differ from their
corresponding functions in <a href="#7.4.1">7.4.1</a> with respect to printing, white-space, single-byte execution
characters other than ' '.
-[<a name="
#p447" href="p447">page 447</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p447" href="#p447">page 447</a>] (<a href="#Contents">Contents</a>)
- Description
+<b> Description</b>
2 The iswspace function tests for any wide character that corresponds to a locale-specific
set of white-space wide characters for which none of iswalnum, iswgraph, or
iswpunct is true.
<a name="7.29.2.1.11" href="#7.29.2.1.11"><b> 7.29.2.1.11 The iswupper function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswupper(wint_t wc);
- Description
+<b> Description</b>
2 The iswupper function tests for any wide character that corresponds to an uppercase
letter or is one of a locale-specific set of wide characters for which none of iswcntrl,
iswdigit, iswpunct, or iswspace is true.
<a name="7.29.2.1.12" href="#7.29.2.1.12"><b> 7.29.2.1.12 The iswxdigit function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswxdigit(wint_t wc);
- Description
+<b> Description</b>
2 The iswxdigit function tests for any wide character that corresponds to a
hexadecimal-digit character (as defined in <a href="#6.4.4.1">6.4.4.1</a>).
<a name="7.29.2.2" href="#7.29.2.2"><b> 7.29.2.2 Extensible wide character classification functions</b></a>
as well as testing equivalent to that performed by the functions described in the previous
subclause (<a href="#7.29.2.1">7.29.2.1</a>).
<a name="7.29.2.2.1" href="#7.29.2.2.1"><b> 7.29.2.2.1 The iswctype function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
int iswctype(wint_t wc, wctype_t desc);
- Description
+<b> Description</b>
2 The iswctype function determines whether the wide character wc has the property
described by desc. The current setting of the LC_CTYPE category shall be the same as
during the call to wctype that returned the value desc.
3 Each of the following expressions has a truth-value equivalent to the call to the wide
character classification function (<a href="#7.29.2.1">7.29.2.1</a>) in the comment that follows the expression:
-
-[<a name="#p448" href="p448">page 448</a>] (<a href="#Contents">Contents</a>)
+[<a name="p448" href="#p448">page 448</a>] (<a href="#Contents">Contents</a>)
iswctype(wc, wctype("alnum")) // iswalnum(wc)
iswctype(wc, wctype("alpha")) // iswalpha(wc)
iswctype(wc, wctype("space")) // iswspace(wc)
iswctype(wc, wctype("upper")) // iswupper(wc)
iswctype(wc, wctype("xdigit")) // iswxdigit(wc)
- Returns
+<b> Returns</b>
4 The iswctype function returns nonzero (true) if and only if the value of the wide
character wc has the property described by desc. If desc is zero, the iswctype
function returns zero (false).
Forward references: the wctype function (<a href="#7.29.2.2.2">7.29.2.2.2</a>).
<a name="7.29.2.2.2" href="#7.29.2.2.2"><b> 7.29.2.2.2 The wctype function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
wctype_t wctype(const char *property);
- Description
+<b> Description</b>
2 The wctype function constructs a value with type wctype_t that describes a class of
wide characters identified by the string argument property.
3 The strings listed in the description of the iswctype function shall be valid in all
locales as property arguments to the wctype function.
- Returns
+<b> Returns</b>
4 If property identifies a valid class of wide characters according to the LC_CTYPE
category of the current locale, the wctype function returns a nonzero value that is valid
as the second argument to the iswctype function; otherwise, it returns zero.
-
-
-
-[<a name="#p449" href="p449">page 449</a>] (<a href="#Contents">Contents</a>)
+[<a name="p449" href="#p449">page 449</a>] (<a href="#Contents">Contents</a>)
<a name="7.29.3" href="#7.29.3"><b> 7.29.3 Wide character case mapping utilities</b></a>
1 The header <a href="#7.29"><wctype.h></a> declares several functions useful for mapping wide characters.
<a name="7.29.3.1" href="#7.29.3.1"><b> 7.29.3.1 Wide character case mapping functions</b></a>
<a name="7.29.3.1.1" href="#7.29.3.1.1"><b> 7.29.3.1.1 The towlower function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
wint_t towlower(wint_t wc);
- Description
+<b> Description</b>
2 The towlower function converts an uppercase letter to a corresponding lowercase letter.
- Returns
+<b> Returns</b>
3 If the argument is a wide character for which iswupper is true and there are one or
more corresponding wide characters, as specified by the current locale, for which
iswlower is true, the towlower function returns one of the corresponding wide
characters (always the same one for any given locale); otherwise, the argument is
returned unchanged.
<a name="7.29.3.1.2" href="#7.29.3.1.2"><b> 7.29.3.1.2 The towupper function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
wint_t towupper(wint_t wc);
- Description
+<b> Description</b>
2 The towupper function converts a lowercase letter to a corresponding uppercase letter.
- Returns
+<b> Returns</b>
3 If the argument is a wide character for which iswlower is true and there are one or
more corresponding wide characters, as specified by the current locale, for which
iswupper is true, the towupper function returns one of the corresponding wide
well as case mapping equivalent to that performed by the functions described in the
previous subclause (<a href="#7.29.3.1">7.29.3.1</a>).
-
-
-
-[<a name="#p450" href="p450">page 450</a>] (<a href="#Contents">Contents</a>)
+[<a name="p450" href="#p450">page 450</a>] (<a href="#Contents">Contents</a>)
<a name="7.29.3.2.1" href="#7.29.3.2.1"><b> 7.29.3.2.1 The towctrans function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
wint_t towctrans(wint_t wc, wctrans_t desc);
- Description
+<b> Description</b>
2 The towctrans function maps the wide character wc using the mapping described by
desc. The current setting of the LC_CTYPE category shall be the same as during the call
to wctrans that returned the value desc.
mapping function (<a href="#7.29.3.1">7.29.3.1</a>) in the comment that follows the expression:
towctrans(wc, wctrans("tolower")) // towlower(wc)
towctrans(wc, wctrans("toupper")) // towupper(wc)
- Returns
+<b> Returns</b>
4 The towctrans function returns the mapped value of wc using the mapping described
by desc. If desc is zero, the towctrans function returns the value of wc.
<a name="7.29.3.2.2" href="#7.29.3.2.2"><b> 7.29.3.2.2 The wctrans function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.29"><wctype.h></a>
wctrans_t wctrans(const char *property);
- Description
+<b> Description</b>
2 The wctrans function constructs a value with type wctrans_t that describes a
mapping between wide characters identified by the string argument property.
3 The strings listed in the description of the towctrans function shall be valid in all
locales as property arguments to the wctrans function.
- Returns
+<b> Returns</b>
4 If property identifies a valid mapping of wide characters according to the LC_CTYPE
category of the current locale, the wctrans function returns a nonzero value that is valid
as the second argument to the towctrans function; otherwise, it returns zero.
-
-
-
-[<a name="#p451" href="p451">page 451</a>] (<a href="#Contents">Contents</a>)
+[<a name="p451" href="#p451">page 451</a>] (<a href="#Contents">Contents</a>)
<a name="7.30" href="#7.30"><b> 7.30 Future library directions</b></a>
1 The following names are grouped under individual headers for convenience. All external
and ending with _MAX, _MIN, or _C may be added to the macros defined in the
<a href="#7.20"><stdint.h></a> header.
-[<a name="
#p452" href="p452">page 452</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p452" href="#p452">page 452</a>] (<a href="#Contents">Contents</a>)
<a name="7.30.9" href="#7.30.9"><b> 7.30.9 Input/output <stdio.h></b></a>
1 Lowercase letters may be added to the conversion specifiers and length modifiers in
1 Function names that begin with is or to and a lowercase letter may be added to the
declarations in the <a href="#7.29"><wctype.h></a> header.
-
-
-
-[<a name="#p453" href="p453">page 453</a>] (<a href="#Contents">Contents</a>)
+[<a name="p453" href="#p453">page 453</a>] (<a href="#Contents">Contents</a>)
<a name="A" href="#A"><b> Annex A</b></a>
(informative)
punctuator
each non-white-space character that cannot be one of the above
-
-
-
-[<a name="#p454" href="p454">page 454</a>] (<a href="#Contents">Contents</a>)
+[<a name="p454" href="#p454">page 454</a>] (<a href="#Contents">Contents</a>)
<a name="A.1.2" href="#A.1.2"><b>A.1.2 Keywords</b></a>
(<a href="#6.4.1">6.4.1</a>) keyword: one of
(<a href="#6.4.2.1">6.4.2.1</a>) digit: one of
0 1 2 3 4 5 6 7 8 9
-
-
-
-[<a name="#p455" href="p455">page 455</a>] (<a href="#Contents">Contents</a>)
+[<a name="p455" href="#p455">page 455</a>] (<a href="#Contents">Contents</a>)
<a name="A.1.4" href="#A.1.4"><b>A.1.4 Universal character names</b></a>
(<a href="#6.4.3">6.4.3</a>) universal-character-name:
(<a href="#6.4.4.1">6.4.4.1</a>) octal-digit: one of
0 1 2 3 4 5 6 7
-
-
-
-[<a name="#p456" href="p456">page 456</a>] (<a href="#Contents">Contents</a>)
+[<a name="p456" href="#p456">page 456</a>] (<a href="#Contents">Contents</a>)
(<a href="#6.4.4.1">6.4.4.1</a>) hexadecimal-digit: one of
0 1 2 3 4 5 6 7 8 9
(<a href="#6.4.4.2">6.4.4.2</a>) sign: one of
+ -
-
-
-[<a name="#p457" href="p457">page 457</a>] (<a href="#Contents">Contents</a>)
+[<a name="p457" href="#p457">page 457</a>] (<a href="#Contents">Contents</a>)
(<a href="#6.4.4.2">6.4.4.2</a>) digit-sequence:
digit
hexadecimal-escape-sequence
universal-character-name
-
-
-
-[<a name="#p458" href="p458">page 458</a>] (<a href="#Contents">Contents</a>)
+[<a name="p458" href="#p458">page 458</a>] (<a href="#Contents">Contents</a>)
(<a href="#6.4.4.4">6.4.4.4</a>) simple-escape-sequence: one of
\' \" \? \\
, # ##
<: :> <% %> %: %:%:
-
-
-
-[<a name="#p459" href="p459">page 459</a>] (<a href="#Contents">Contents</a>)
+[<a name="p459" href="#p459">page 459</a>] (<a href="#Contents">Contents</a>)
<a name="A.1.8" href="#A.1.8"><b>A.1.8 Header names</b></a>
(<a href="#6.4.7">6.4.7</a>) header-name:
pp-number P sign
pp-number .
-
-
-
-[<a name="#p460" href="p460">page 460</a>] (<a href="#Contents">Contents</a>)
+[<a name="p460" href="#p460">page 460</a>] (<a href="#Contents">Contents</a>)
<a name="A.2" href="#A.2"><b>A.2 Phrase structure grammar</b></a>
<a name="A.2.1" href="#A.2.1"><b>A.2.1 Expressions</b></a>
sizeof ( type-name )
alignof ( type-name )
-[<a name="
#p461" href="p461">page 461</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p461" href="#p461">page 461</a>] (<a href="#Contents">Contents</a>)
(<a href="#6.5.3">6.5.3</a>) unary-operator: one of
& * + - ~ !
AND-expression
exclusive-OR-expression ^ AND-expression
-
-
-
-[<a name="#p462" href="p462">page 462</a>] (<a href="#Contents">Contents</a>)
+[<a name="p462" href="#p462">page 462</a>] (<a href="#Contents">Contents</a>)
(<a href="#6.5.12">6.5.12</a>) inclusive-OR-expression:
exclusive-OR-expression
init-declarator
init-declarator-list , init-declarator
-
-[<a name="#p463" href="p463">page 463</a>] (<a href="#Contents">Contents</a>)
+[<a name="p463" href="#p463">page 463</a>] (<a href="#Contents">Contents</a>)
(<a href="#6.7">6.7</a>) init-declarator:
declarator
specifier-qualifier-list struct-declarator-listopt ;
static_assert-declaration
-[<a name="
#p464" href="p464">page 464</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p464" href="#p464">page 464</a>] (<a href="#Contents">Contents</a>)
(<a href="#6.7.2.1">6.7.2.1</a>) specifier-qualifier-list:
type-specifier specifier-qualifier-listopt
(<a href="#6.7.6">6.7.6</a>) declarator:
pointeropt direct-declarator
-
-
-[<a name="#p465" href="p465">page 465</a>] (<a href="#Contents">Contents</a>)
+[<a name="p465" href="#p465">page 465</a>] (<a href="#Contents">Contents</a>)
(<a href="#6.7.6">6.7.6</a>) direct-declarator:
identifier
pointer
pointeropt direct-abstract-declarator
-
-
-
-[<a name="#p466" href="p466">page 466</a>] (<a href="#Contents">Contents</a>)
+[<a name="p466" href="#p466">page 466</a>] (<a href="#Contents">Contents</a>)
(<a href="#6.7.7">6.7.7</a>) direct-abstract-declarator:
( abstract-declarator )
(<a href="#6.7.10">6.7.10</a>) static_assert-declaration:
_Static_assert ( constant-expression , string-literal ) ;
-
-
-
-[<a name="#p467" href="p467">page 467</a>] (<a href="#Contents">Contents</a>)
+[<a name="p467" href="#p467">page 467</a>] (<a href="#Contents">Contents</a>)
<a name="A.2.3" href="#A.2.3"><b>A.2.3 Statements</b></a>
(<a href="#6.8">6.8</a>) statement:
break ;
return expressionopt ;
-[<a name="
#p468" href="p468">page 468</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p468" href="#p468">page 468</a>] (<a href="#Contents">Contents</a>)
<a name="A.2.4" href="#A.2.4"><b>A.2.4 External definitions</b></a>
(<a href="#6.9">6.9</a>) translation-unit:
(<a href="#6.10">6.10</a>) elif-group:
# elif constant-expression new-line groupopt
-
-[<a name="#p469" href="p469">page 469</a>] (<a href="#Contents">Contents</a>)
+[<a name="p469" href="#p469">page 469</a>] (<a href="#Contents">Contents</a>)
(<a href="#6.10">6.10</a>) else-group:
# else new-line groupopt
(<a href="#6.10">6.10</a>) new-line:
the new-line character
-
-
-
-[<a name="#p470" href="p470">page 470</a>] (<a href="#Contents">Contents</a>)
+[<a name="p470" href="#p470">page 470</a>] (<a href="#Contents">Contents</a>)
<a name="B" href="#B"><b> Annex B</b></a>
(informative)
float complex casinhf(float complex z);
long double complex casinhl(long double complex z);
-[<a name="
#p471" href="p471">page 471</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p471" href="#p471">page 471</a>] (<a href="#Contents">Contents</a>)
double complex catanh(double complex z);
float complex catanhf(float complex z);
long double complex conjl(long double complex z);
double complex cproj(double complex z);
-[<a name="
#p472" href="p472">page 472</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p472" href="#p472">page 472</a>] (<a href="#Contents">Contents</a>)
float complex cprojf(float complex z);
long double complex cprojl(long double complex z);
int excepts);
int fetestexcept(int excepts);
-[<a name="
#p473" href="p473">page 473</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p473" href="#p473">page 473</a>] (<a href="#Contents">Contents</a>)
int fegetround(void);
int fesetround(int round);
intmax_t strtoimax(const char * restrict nptr,
char ** restrict endptr, int base);
-[<a name="
#p474" href="p474">page 474</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p474" href="#p474">page 474</a>] (<a href="#Contents">Contents</a>)
uintmax_t strtoumax(const char * restrict nptr,
char ** restrict endptr, int base);
int isnan(real-floating x);
int isnormal(real-floating x);
int signbit(real-floating x);
-[<a name="#p475" href="p475">page 475</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p475" href="#p475">page 475</a>] (<a href="#Contents">Contents</a>)
double acos(double x);
float acosf(float x);
double exp(double x);
float expf(float x);
-[<a name="
#p476" href="p476">page 476</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p476" href="#p476">page 476</a>] (<a href="#Contents">Contents</a>)
long double expl(long double x);
double exp2(double x);
long double scalblnl(long double x, long int n);
double cbrt(double x);
-[<a name="
#p477" href="p477">page 477</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p477" href="#p477">page 477</a>] (<a href="#Contents">Contents</a>)
float cbrtf(float x);
long double cbrtl(long double x);
long int lrintf(float x);
long int lrintl(long double x);
-[<a name="
#p478" href="p478">page 478</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p478" href="#p478">page 478</a>] (<a href="#Contents">Contents</a>)
long long int llrint(double x);
long long int llrintf(float x);
long double fdiml(long double x, long double y);
double fmax(double x, double y);
-[<a name="
#p479" href="p479">page 479</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p479" href="#p479">page 479</a>] (<a href="#Contents">Contents</a>)
float fmaxf(float x, float y);
long double fmaxl(long double x, long double y);
void (*signal(int sig, void (*func)(int)))(int);
int raise(int sig);
-
-
-
-[<a name="#p480" href="p480">page 480</a>] (<a href="#Contents">Contents</a>)
+[<a name="p480" href="#p480">page 480</a>] (<a href="#Contents">Contents</a>)
<a name="B.14" href="#B.14"><b>B.14 Alignment <stdalign.h></b></a>
alignas
atomic_ushort atomic_intptr_t
atomic_int atomic_uintptr_t
-
-
-[<a name="#p481" href="p481">page 481</a>] (<a href="#Contents">Contents</a>)
+[<a name="p481" href="#p481">page 481</a>] (<a href="#Contents">Contents</a>)
atomic_size_t atomic_intmax_t
atomic_ptrdiff_t atomic_uintmax_t
void atomic_flag_clear_explicit(
volatile atomic_flag *object, memory_order order);
-
-
-
-[<a name="#p482" href="p482">page 482</a>] (<a href="#Contents">Contents</a>)
+[<a name="p482" href="#p482">page 482</a>] (<a href="#Contents">Contents</a>)
<a name="B.17" href="#B.17"><b>B.17 Boolean type and values <stdbool.h></b></a>
bool
__STDC_WANT_LIB_EXT1__
RSIZE_MAX
-
-
-
-[<a name="#p483" href="p483">page 483</a>] (<a href="#Contents">Contents</a>)
+[<a name="p483" href="#p483">page 483</a>] (<a href="#Contents">Contents</a>)
<a name="B.20" href="#B.20"><b>B.20 Input/output <stdio.h></b></a>
size_t _IOLBF FILENAME_MAX TMP_MAX
int vprintf(const char * restrict format, va_list arg);
int vscanf(const char * restrict format, va_list arg);
-[<a name="
#p484" href="p484">page 484</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p484" href="#p484">page 484</a>] (<a href="#Contents">Contents</a>)
int vsnprintf(char * restrict s, size_t n,
const char * restrict format, va_list arg);
errno_t tmpfile_s(FILE * restrict * restrict streamptr);
errno_t tmpnam_s(char *s, rsize_t maxsize);
-
-
-[<a name="#p485" href="p485">page 485</a>] (<a href="#Contents">Contents</a>)
+[<a name="p485" href="#p485">page 485</a>] (<a href="#Contents">Contents</a>)
errno_t fopen_s(FILE * restrict * restrict streamptr,
const char * restrict filename,
va_list arg);
char *gets_s(char *s, rsize_t n);
-
-
-[<a name="#p486" href="p486">page 486</a>] (<a href="#Contents">Contents</a>)
+[<a name="p486" href="#p486">page 486</a>] (<a href="#Contents">Contents</a>)
<a name="B.21" href="#B.21"><b>B.21 General utilities <stdlib.h></b></a>
size_t ldiv_t EXIT_FAILURE MB_CUR_MAX
_Noreturn void quick_exit(int status);
int system(const char *string);
-
-[<a name="#p487" href="p487">page 487</a>] (<a href="#Contents">Contents</a>)
+[<a name="p487" href="#p487">page 487</a>] (<a href="#Contents">Contents</a>)
void *bsearch(const void *key, const void *base,
size_t nmemb, size_t size,
char * restrict value, rsize_t maxsize,
const char * restrict name);
-
-
-
-[<a name="#p488" href="p488">page 488</a>] (<a href="#Contents">Contents</a>)
+[<a name="p488" href="#p488">page 488</a>] (<a href="#Contents">Contents</a>)
void *bsearch_s(const void *key, const void *base,
rsize_t nmemb, rsize_t size,
size_t strxfrm(char * restrict s1,
const char * restrict s2, size_t n);
void *memchr(const void *s, int c, size_t n);
-[<a name="#p489" href="p489">page 489</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p489" href="#p489">page 489</a>] (<a href="#Contents">Contents</a>)
char *strchr(const char *s, int c);
size_t strcspn(const char *s1, const char *s2);
errno_t errnum);
size_t strerrorlen_s(errno_t errnum);
-[<a name="
#p490" href="p490">page 490</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p490" href="#p490">page 490</a>] (<a href="#Contents">Contents</a>)
size_t strnlen_s(const char *s, size_t maxsize);
<a name="B.23" href="#B.23"><b>B.23 Type-generic math <tgmath.h></b></a>
void mtx_destroy(mtx_t *mtx);
int mtx_init(mtx_t *mtx, int type);
int mtx_lock(mtx_t *mtx);
-[<a name="#p491" href="p491">page 491</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p491" href="#p491">page 491</a>] (<a href="#Contents">Contents</a>)
int mtx_timedlock(mtx_t *mtx, const xtime *xt);
int mtx_trylock(mtx_t *mtx);
errno_t asctime_s(char *s, rsize_t maxsize,
const struct tm *timeptr);
-
-
-[<a name="#p492" href="p492">page 492</a>] (<a href="#Contents">Contents</a>)
+[<a name="p492" href="#p492">page 492</a>] (<a href="#Contents">Contents</a>)
errno_t ctime_s(char *s, rsize_t maxsize,
const time_t *timer);
int vswprintf(wchar_t * restrict s, size_t n,
const wchar_t * restrict format, va_list arg);
-
-
-[<a name="#p493" href="p493">page 493</a>] (<a href="#Contents">Contents</a>)
+[<a name="p493" href="#p493">page 493</a>] (<a href="#Contents">Contents</a>)
int vswscanf(const wchar_t * restrict s,
const wchar_t * restrict format, va_list arg);
wchar_t *wcsncpy(wchar_t * restrict s1,
const wchar_t * restrict s2, size_t n);
-
-
-[<a name="#p494" href="p494">page 494</a>] (<a href="#Contents">Contents</a>)
+[<a name="p494" href="#p494">page 494</a>] (<a href="#Contents">Contents</a>)
wchar_t *wmemcpy(wchar_t * restrict s1,
const wchar_t * restrict s2, size_t n);
const char * restrict s, size_t n,
mbstate_t * restrict ps);
-
-
-[<a name="#p495" href="p495">page 495</a>] (<a href="#Contents">Contents</a>)
+[<a name="p495" href="#p495">page 495</a>] (<a href="#Contents">Contents</a>)
size_t wcrtomb(char * restrict s, wchar_t wc,
mbstate_t * restrict ps);
const wchar_t * restrict format,
va_list arg);
-
-
-[<a name="#p496" href="p496">page 496</a>] (<a href="#Contents">Contents</a>)
+[<a name="p496" href="#p496">page 496</a>] (<a href="#Contents">Contents</a>)
int vwprintf_s(const wchar_t * restrict format,
va_list arg);
const char ** restrict src, rsize_t len,
mbstate_t * restrict ps);
-
-
-
-[<a name="#p497" href="p497">page 497</a>] (<a href="#Contents">Contents</a>)
+[<a name="p497" href="#p497">page 497</a>] (<a href="#Contents">Contents</a>)
errno_t wcsrtombs_s(size_t * restrict retval,
char * restrict dst, rsize_t dstmax,
wint_t towctrans(wint_t wc, wctrans_t desc);
wctrans_t wctrans(const char *property);
-
-
-
-[<a name="#p498" href="p498">page 498</a>] (<a href="#Contents">Contents</a>)
+[<a name="p498" href="#p498">page 498</a>] (<a href="#Contents">Contents</a>)
<a name="C" href="#C"><b> Annex C</b></a>
(informative)
also between any call to a comparison function and any movement of the objects
passed as arguments to that call (<a href="#7.22.5">7.22.5</a>).
-
-
-
-[<a name="#p499" href="p499">page 499</a>] (<a href="#Contents">Contents</a>)
+[<a name="p499" href="#p499">page 499</a>] (<a href="#Contents">Contents</a>)
<a name="D" href="#D"><b> Annex D</b></a>
(normative)
<a name="D.2" href="#D.2"><b> D.2 Ranges of characters disallowed initially</b></a>
1 0300-036F, 1DC0-1DFF, 20D0-20FF, FE20-FE2F
-
-
-
-[<a name="#p500" href="p500">page 500</a>] (<a href="#Contents">Contents</a>)
+[<a name="p500" href="#p500">page 500</a>] (<a href="#Contents">Contents</a>)
<a name="E" href="#E"><b> Annex E</b></a>
(informative)
4 The values given in the following list shall be replaced by implementation-defined
constant expressions that are greater or equal in magnitude (absolute value) to those
shown, with the same sign:
-[<a name="#p501" href="p501">page 501</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p501" href="#p501">page 501</a>] (<a href="#Contents">Contents</a>)
#define DLB_DECIMAL_DIG 10
#define DBL_DIG 10
#define LDBL_EPSILON 1E-9
#define LDBL_MIN 1E-37
-
-
-
-[<a name="#p502" href="p502">page 502</a>] (<a href="#Contents">Contents</a>)
+[<a name="p502" href="#p502">page 502</a>] (<a href="#Contents">Contents</a>)
<a name="F" href="#F"><b> Annex F</b></a>
(normative)
Arithmetic (ANSI/IEEE 854-1987) generalizes the binary standard to remove
dependencies on radix and word length. IEC 60559 generally refers to the floating-point
standard, as in IEC 60559 operation, IEC 60559 format, etc. An implementation that
- defines __STDC_IEC_559__ shall conform to the specifications in this annex.343)
+ defines __STDC_IEC_559__ shall conform to the specifications in this annex.<sup><a href="#note343"><b>343)</b></a></sup>
Where a binding between the C language and IEC 60559 is indicated, the
IEC 60559-specified behavior is adopted by reference, unless stated otherwise. Since
negative and positive infinity are representable in IEC 60559 formats, all real numbers lie
1 The C floating types match the IEC 60559 formats as follows:
-- The float type matches the IEC 60559 single format.
-- The double type matches the IEC 60559 double format.
- -- The long double type matches an IEC 60559 extended format,344) else a
+ -- The long double type matches an IEC 60559 extended format,<sup><a href="#note344"><b>344)</b></a></sup> else a
non-IEC 60559 extended format, else the IEC 60559 double format.
Any non-IEC 60559 extended format used for the long double type shall have more
- precision than IEC 60559 double and at least the range of IEC 60559 double.345)
+ precision than IEC 60559 double and at least the range of IEC 60559 double.<sup><a href="#note345"><b>345)</b></a></sup>
- 343) Implementations that do not define __STDC_IEC_559__ are not required to conform to these
+ <sup><a name="note343" href="#note343"><b>343)</b></a></sup> Implementations that do not define __STDC_IEC_559__ are not required to conform to these
specifications.
- 344) ''Extended'' is IEC 60559's double-extended data format. Extended refers to both the common 80-bit
+ <sup><a name="note344" href="#note344"><b>344)</b></a></sup> ''Extended'' is IEC 60559's double-extended data format. Extended refers to both the common 80-bit
and quadruple 128-bit IEC 60559 formats.
- 345) A non-IEC 60559 long double type is required to provide infinity and NaNs, as its values include
+ <sup><a name="note345" href="#note345"><b>345)</b></a></sup> A non-IEC 60559 long double type is required to provide infinity and NaNs, as its values include
all double values.
-[<a name="
#p503" href="p503">page 503</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p503" href="#p503">page 503</a>] (<a href="#Contents">Contents</a>)
Recommended practice
2 The long double type should match an IEC 60559 extended format.
<a name="F.2.1" href="#F.2.1"><b> F.2.1 Infinities, signed zeros, and NaNs</b></a>
-1 This specification does not define the behavior of signaling NaNs.346) It generally uses
+1 This specification does not define the behavior of signaling NaNs.<sup><a href="#note346"><b>346)</b></a></sup> It generally uses
the term NaN to denote quiet NaNs. The NAN and INFINITY macros and the nan
functions in <a href="#7.12"><math.h></a> provide designations for IEC 60559 NaNs and infinities.
<a name="F.3" href="#F.3"><b> F.3 Operators and functions</b></a>
strtold, fprintf, fscanf, and related library functions in <a href="#7.22"><stdlib.h></a>,
- 346) Since NaNs created by IEC 60559 operations are always quiet, quiet NaNs (along with infinities) are
+ <sup><a name="note346" href="#note346"><b>346)</b></a></sup> Since NaNs created by IEC 60559 operations are always quiet, quiet NaNs (along with infinities) are
sufficient for closure of the arithmetic.
-[<a name="
#p504" href="p504">page 504</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p504" href="#p504">page 504</a>] (<a href="#Contents">Contents</a>)
<a href="#7.21"><stdio.h></a>, and <a href="#7.28"><wchar.h></a> provide IEC 60559 binary-decimal conversions. The
strtold function in <a href="#7.22"><stdlib.h></a> provides the conv function recommended in the
-- The nextafter and nexttoward functions in <a href="#7.12"><math.h></a> provide the nextafter
function recommended in the Appendix to IEC 60559 (but with a minor change to
-[<a name="
#p505" href="p505">page 505</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p505" href="#p505">page 505</a>] (<a href="#Contents">Contents</a>)
better handle signed zeros).
-- The isfinite macro in <a href="#7.12"><math.h></a> provides the finite function recommended in
value is determined by <a href="#6.3.1.4">6.3.1.4</a>. Conversion of an integral floating value that does not
exceed the range of the integer type raises no floating-point exceptions; whether
conversion of a non-integral floating value raises the ''inexact'' floating-point exception is
- unspecified.347)
+ unspecified.<sup><a href="#note347"><b>347)</b></a></sup>
<a name="F.5" href="#F.5"><b> F.5 Binary-decimal conversion</b></a>
1 Conversion from the widest supported IEC 60559 format to decimal with
- DECIMAL_DIG digits and back is the identity function.348)
+ DECIMAL_DIG digits and back is the identity function.<sup><a href="#note348"><b>348)</b></a></sup>
2 Conversions involving IEC 60559 formats follow all pertinent recommended practice. In
particular, conversion between any supported IEC 60559 format and decimal with
DECIMAL_DIG or fewer significant digits is correctly rounded (honoring the current
- 347) ANSI/IEEE 854, but not IEC 60559 (ANSI/IEEE 754), directly specifies that floating-to-integer
+ <sup><a name="note347" href="#note347"><b>347)</b></a></sup> ANSI/IEEE 854, but not IEC 60559 (ANSI/IEEE 754), directly specifies that floating-to-integer
conversions raise the ''inexact'' floating-point exception for non-integer in-range values. In those
cases where it matters, library functions can be used to effect such conversions with or without raising
the ''inexact'' floating-point exception. See rint, lrint, llrint, and nearbyint in
<a href="#7.12"><math.h></a>.
- 348) If the minimum-width IEC 60559 extended format (64 bits of precision) is supported,
+ <sup><a name="note348" href="#note348"><b>348)</b></a></sup> If the minimum-width IEC 60559 extended format (64 bits of precision) is supported,
DECIMAL_DIG shall be at least 21. If IEC 60559 double (53 bits of precision) is the widest
IEC 60559 format supported, then DECIMAL_DIG shall be at least 17. (By contrast, LDBL_DIG and
DBL_DIG are 18 and 15, respectively, for these formats.)
-[<a name="
#p506" href="p506">page 506</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p506" href="#p506">page 506</a>] (<a href="#Contents">Contents</a>)
3 Functions such as strtod that convert character sequences to floating types honor the
rounding direction. Hence, if the rounding direction might be upward or downward, the
unsigned sequence.
<a name="F.6" href="#F.6"><b> F.6 The return statement</b></a>
If the return expression is evaluated in a floating-point format different from the return
- type, the expression is converted as if by assignment349) to the return type of the function
+ type, the expression is converted as if by assignment<sup><a href="#note349"><b>349)</b></a></sup> to the return type of the function
and the resulting value is returned to the caller.
<a name="F.7" href="#F.7"><b> F.7 Contracted expressions</b></a>
1 A contracted expression is correctly rounded (once) and treats infinities, NaNs, signed
1 The floating-point environment defined in <a href="#7.6"><fenv.h></a> includes the IEC 60559 floating-
point exception status flags and directed-rounding control modes. It includes also
IEC 60559 dynamic rounding precision and trap enablement modes, if the
- implementation supports them.350)
+ implementation supports them.<sup><a href="#note350"><b>350)</b></a></sup>
<a name="F.8.1" href="#F.8.1"><b> F.8.1 Environment management</b></a>
1 IEC 60559 requires that floating-point operations implicitly raise floating-point exception
status flags, and that rounding control modes can be set explicitly to affect result values of
floating-point operations. When the state for the FENV_ACCESS pragma (defined in
<a href="#7.6"><fenv.h></a>) is ''on'', these changes to the floating-point state are treated as side effects
- which respect sequence points.351)
+ which respect sequence points.<sup><a href="#note351"><b>351)</b></a></sup>
- 349) Assignment removes any extra range and precision.
- 350) This specification does not require dynamic rounding precision nor trap enablement modes.
- 351) If the state for the FENV_ACCESS pragma is ''off'', the implementation is free to assume the floating-
+ <sup><a name="note349" href="#note349"><b>349)</b></a></sup> Assignment removes any extra range and precision.
+ <sup><a name="note350" href="#note350"><b>350)</b></a></sup> This specification does not require dynamic rounding precision nor trap enablement modes.
+ <sup><a name="note351" href="#note351"><b>351)</b></a></sup> If the state for the FENV_ACCESS pragma is ''off'', the implementation is free to assume the floating-
point control modes will be the default ones and the floating-point status flags will not be tested,
which allows certain optimizations (see <a href="#F.9">F.9</a>).
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+[<a name="
p507" href="#p507">page 507</a>] (<a href="#Contents">Contents</a>)
<a name="F.8.2" href="#F.8.2"><b> F.8.2 Translation</b></a>
1 During translation the IEC 60559 default modes are in effect:
-- Trapping or stopping (if supported) is disabled on all floating-point exceptions.
Recommended practice
2 The implementation should produce a diagnostic message for each translation-time
- floating-point exception, other than ''inexact'';352) the implementation should then
+ floating-point exception, other than ''inexact'';<sup><a href="#note352"><b>352)</b></a></sup> the implementation should then
proceed with the translation of the program.
<a name="F.8.3" href="#F.8.3"><b> F.8.3 Execution</b></a>
1 At program startup the floating-point environment is initialized as prescribed by
object that has static or thread storage duration, is evaluated (as if) during execution; thus,
it is affected by any operative floating-point control modes and raises floating-point
exceptions as required by IEC 60559 (provided the state for the FENV_ACCESS pragma
- is ''on'').353)
+ is ''on'').<sup><a href="#note353"><b>353)</b></a></sup>
2 EXAMPLE
- 352) As floating constants are converted to appropriate internal representations at translation time, their
+ <sup><a name="note352" href="#note352"><b>352)</b></a></sup> As floating constants are converted to appropriate internal representations at translation time, their
conversion is subject to default rounding modes and raises no execution-time floating-point exceptions
(even where the state of the FENV_ACCESS pragma is ''on''). Library functions, for example
strtod, provide execution-time conversion of numeric strings.
- 353) Where the state for the FENV_ACCESS pragma is ''on'', results of inexact expressions like <a href="#1.0">1.0</a>/3.0
+ <sup><a name="note353" href="#note353"><b>353)</b></a></sup> Where the state for the FENV_ACCESS pragma is ''on'', results of inexact expressions like 1.0/3.0
are affected by rounding modes set at execution time, and expressions such as 0.0/0.0 and
- <a href="#1.0">1.0</a>/0.0 generate execution-time floating-point exceptions. The programmer can achieve the
+ 1.0/0.0 generate execution-time floating-point exceptions. The programmer can achieve the
efficiency of translation-time evaluation through static initialization, such as
- const static double one_third = <a href="#1.0">1.0</a>/3.0;
-
+ const static double one_third = 1.0/3.0;
-[<a name="
#p508" href="p508">page 508</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p508" href="#p508">page 508</a>] (<a href="#Contents">Contents</a>)
#include <a href="#7.6"><fenv.h></a>
#pragma STDC FENV_ACCESS ON
done at translation time. The automatic initialization of u and w require an execution-time conversion to
float of the wider value 1.1e75, which raises floating-point exceptions. The automatic initializations
of x and y entail execution-time conversion; however, in some expression evaluation methods, the
- conversions is not to a narrower format, in which case no floating-point exception is raised.354) The
+ conversions is not to a narrower format, in which case no floating-point exception is raised.<sup><a href="#note354"><b>354)</b></a></sup> The
automatic initialization of z entails execution-time conversion, but not to a narrower format, so no floating-
point exception is raised. Note that the conversions of the floating constants 1.1e75 and 1.1e75f to
- 354) Use of float_t and double_t variables increases the likelihood of translation-time computation.
+ <sup><a name="note354" href="#note354"><b>354)</b></a></sup> Use of float_t and double_t variables increases the likelihood of translation-time computation.
For example, the automatic initialization
double_t x = 1.1e75;
could be done at translation time, regardless of the expression evaluation method.
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their internal representations occur at translation time in all cases.
about the order or count of floating-point exceptions. Therefore, between function calls,
floating-point exceptions need not be precise: the actual order and number of occurrences
of floating-point exceptions (> 1) may vary from what the source code expresses. Thus,
-[<a name="#p510" href="p510">page 510</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p510" href="#p510">page 510</a>] (<a href="#Contents">Contents</a>)
the preceding loop could be treated as
if (0 < n) x + 1;
<a name="F.9.2" href="#F.9.2"><b> F.9.2 Expression transformations</b></a>
-1 x/2 (<->) x x 0.5 Although similar transformations involving inexact constants
+1 x/2 <-> x x 0.5 Although similar transformations involving inexact constants
generally do not yield numerically equivalent expressions, if the
constants are exact then such transformations can be made on
IEC 60559 machines and others that round perfectly.
- 1 x x and x/1 (->) x The expressions 1 x x, x/1, and x are equivalent (on IEC 60559
- machines, among others).355)
- x/x (->) <a href="#1.0">1.0</a> The expressions x/x and <a href="#1.0">1.0</a> are not equivalent if x can be zero,
+ 1 x x and x/1 -> x The expressions 1 x x, x/1, and x are equivalent (on IEC 60559
+ machines, among others).<sup><a href="#note355"><b>355)</b></a></sup>
+ x/x -> 1.0 The expressions x/x and 1.0 are not equivalent if x can be zero,
infinite, or NaN.
- x - y (<->) x + (-y) The expressions x - y, x + (-y), and (-y) + x are equivalent (on
+ x - y <-> x + (-y) The expressions x - y, x + (-y), and (-y) + x are equivalent (on
IEC 60559 machines, among others).
- x - y (<->) -(y - x) The expressions x - y and -(y - x) are not equivalent because 1 - 1
- is +0 but -(1 - 1) is -0 (in the default rounding direction).356)
- x - x (->) 0.0 The expressions x - x and 0.0 are not equivalent if x is a NaN or
+ x - y <-> -(y - x) The expressions x - y and -(y - x) are not equivalent because 1 - 1
+ is +0 but -(1 - 1) is -0 (in the default rounding direction).<sup><a href="#note356"><b>356)</b></a></sup>
+ x - x -> 0.0 The expressions x - x and 0.0 are not equivalent if x is a NaN or
infinite.
- 0 x x (->) 0.0 The expressions 0 x x and 0.0 are not equivalent if x is a NaN,
+ 0 x x -> 0.0 The expressions 0 x x and 0.0 are not equivalent if x is a NaN,
infinite, or -0.
- x+0(->) x The expressions x + 0 and x are not equivalent if x is -0, because
+ x+0-> x The expressions x + 0 and x are not equivalent if x is -0, because
(-0) + (+0) yields +0 (in the default rounding direction), not -0.
- x-0(->) x (+0) - (+0) yields -0 when rounding is downward (toward -(inf)), but
+ x-0-> x (+0) - (+0) yields -0 when rounding is downward (toward -(inf)), but
+0 otherwise, and (-0) - (+0) always yields -0; so, if the state of the
FENV_ACCESS pragma is ''off'', promising default rounding, then
the implementation can replace x - 0 by x, even if x might be zero.
- -x (<->) 0 - x The expressions -x and 0 - x are not equivalent if x is +0, because
+ -x <-> 0 - x The expressions -x and 0 - x are not equivalent if x is +0, because
-(+0) yields -0, but 0 - (+0) yields +0 (unless rounding is
downward).
- 355) Strict support for signaling NaNs -- not required by this specification -- would invalidate these and
+ <sup><a name="note355" href="#note355"><b>355)</b></a></sup> Strict support for signaling NaNs -- not required by this specification -- would invalidate these and
other transformations that remove arithmetic operators.
- 356) IEC 60559 prescribes a signed zero to preserve mathematical identities across certain discontinuities.
+ <sup><a name="note356" href="#note356"><b>356)</b></a></sup> IEC 60559 prescribes a signed zero to preserve mathematical identities across certain discontinuities.
Examples include:
1/(1/ (+-) (inf)) is (+-) (inf)
and
conj(csqrt(z)) is csqrt(conj(z)),
for complex z.
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#p511" href="p511">page 511</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p511" href="#p511">page 511</a>] (<a href="#Contents">Contents</a>)
<a name="F.9.3" href="#F.9.3"><b> F.9.3 Relational operators</b></a>
-1 x != x (->) false The expression x != x is true if x is a NaN.
- x = x (->) true The expression x = x is false if x is a NaN.
- x < y (->) isless(x,y) (and similarly for <=, >, >=) Though numerically equal, these
+1 x != x -> false The expression x != x is true if x is a NaN.
+ x = x -> true The expression x = x is false if x is a NaN.
+ x < y -> isless(x,y) (and similarly for <=, >, >=) Though numerically equal, these
expressions are not equivalent because of side effects when x or y is a
NaN and the state of the FENV_ACCESS pragma is ''on''. This
transformation, which would be desirable if extra code were required
g();
but is equivalent to
-
-
-
-[<a name="#p512" href="p512">page 512</a>] (<a href="#Contents">Contents</a>)
+[<a name="p512" href="#p512">page 512</a>] (<a href="#Contents">Contents</a>)
if (!(a < b))
g();
and <a href="#F.8.5">F.8.5</a>.) An operation on constants that raises no floating-point exception can be
folded during translation, except, if the state of the FENV_ACCESS pragma is ''on'', a
further check is required to assure that changing the rounding direction to downward does
- not alter the sign of the result,357) and implementations that support dynamic rounding
+ not alter the sign of the result,<sup><a href="#note357"><b>357)</b></a></sup> and implementations that support dynamic rounding
precision modes shall assure further that the result of the operation raises no floating-
point exception when converted to the semantic type of the operation.
<a name="F.10" href="#F.10"><b> F.10 Mathematics <math.h></b></a>
rounding direction, a maximal-magnitude finite number -- is returned in lieu of a value
whose magnitude is too large.
7 The ''underflow'' floating-point exception is raised whenever a result is tiny (essentially
- subnormal or zero) and suffers loss of accuracy.358)
+ subnormal or zero) and suffers loss of accuracy.<sup><a href="#note358"><b>358)</b></a></sup>
- 357) 0 - 0 yields -0 instead of +0 just when the rounding direction is downward.
- 358) IEC 60559 allows different definitions of underflow. They all result in the same values, but differ on
+ <sup><a name="note357" href="#note357"><b>357)</b></a></sup> 0 - 0 yields -0 instead of +0 just when the rounding direction is downward.
+ <sup><a name="note358" href="#note358"><b>358)</b></a></sup> IEC 60559 allows different definitions of underflow. They all result in the same values, but differ on
when the floating-point exception is raised.
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8 Whether or when library functions raise the ''inexact'' floating-point exception is
unspecified, unless explicitly specified otherwise.
9 Whether or when library functions raise an undeserved ''underflow'' floating-point
- exception is unspecified.
359) Otherwise, as implied by <a href="#F.8.6">F.8.6</a>, the <a href="#7.12"><math.h></a> functions do
+ exception is unspecified.
<sup><a href="#note359"><b>359)</b></a></sup> Otherwise, as implied by <a href="#F.8.6">F.8.6</a>, the <a href="#7.12"><math.h></a> functions do
not raise spurious floating-point exceptions (detectable by the user), other than the
''inexact'' floating-point exception.
10 Whether the functions honor the rounding direction mode is implementation-defined,
- 359) It is intended that undeserved ''underflow'' and ''inexact'' floating-point exceptions are raised only if
+ <sup><a name="note359" href="#note359"><b>359)</b></a></sup> It is intended that undeserved ''underflow'' and ''inexact'' floating-point exceptions are raised only if
avoiding them would be too costly.
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#p514" href="p514">page 514</a>] (<a href="#Contents">Contents</a>)
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p514" href="#p514">page 514</a>] (<a href="#Contents">Contents</a>)
<a name="F.10.1.3" href="#F.10.1.3"><b> F.10.1.3 The atan functions</b></a>
1 -- atan((+-)0) returns (+-)0.
-- atan((+-)(inf)) returns (+-)pi /2.
<a name="F.10.1.4" href="#F.10.1.4"><b> F.10.1.4 The atan2 functions</b></a>
-1 -- atan2((+-)0, -0) returns (+-)pi .360)
+1 -- atan2((+-)0, -0) returns (+-)pi .<sup><a href="#note360"><b>360)</b></a></sup>
-- atan2((+-)0, +0) returns (+-)0.
-- atan2((+-)0, x) returns (+-)pi for x < 0.
-- atan2((+-)0, x) returns (+-)0 for x > 0.
- 360) atan2(0, 0) does not raise the ''invalid'' floating-point exception, nor does atan2( y , 0) raise
+ <sup><a name="note360" href="#note360"><b>360)</b></a></sup> atan2(0, 0) does not raise the ''invalid'' floating-point exception, nor does atan2( y , 0) raise
the ''divide-by-zero'' floating-point exception.
-[<a name="
#p515" href="p515">page 515</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p515" href="#p515">page 515</a>] (<a href="#Contents">Contents</a>)
<a name="F.10.2" href="#F.10.2"><b> F.10.2 Hyperbolic functions</b></a>
<a name="F.10.2.1" href="#F.10.2.1"><b> F.10.2.1 The acosh functions</b></a>
-- exp(-(inf)) returns +0.
-- exp(+(inf)) returns +(inf).
-
-
-
-[<a name="#p516" href="p516">page 516</a>] (<a href="#Contents">Contents</a>)
+[<a name="p516" href="#p516">page 516</a>] (<a href="#Contents">Contents</a>)
<a name="F.10.3.2" href="#F.10.3.2"><b> F.10.3.2 The exp2 functions</b></a>
1 -- exp2((+-)0) returns 1.
2 If the correct result is outside the range of the return type, the numeric result is
unspecified and the ''invalid'' floating-point exception is raised.
-
-
-
-[<a name="#p517" href="p517">page 517</a>] (<a href="#Contents">Contents</a>)
+[<a name="p517" href="#p517">page 517</a>] (<a href="#Contents">Contents</a>)
<a name="F.10.3.6" href="#F.10.3.6"><b> F.10.3.6 The ldexp functions</b></a>
1 On a binary system, ldexp(x, exp) is equivalent to scalbn(x, exp).
-- logb((+-)(inf)) returns +(inf).
2 The returned value is exact and is independent of the current rounding direction mode.
-
-
-
-[<a name="#p518" href="p518">page 518</a>] (<a href="#Contents">Contents</a>)
+[<a name="p518" href="#p518">page 518</a>] (<a href="#Contents">Contents</a>)
<a name="F.10.3.12" href="#F.10.3.12"><b> F.10.3.12 The modf functions</b></a>
1 -- modf((+-)x, iptr) returns a result with the same sign as x.
2 If the calculation does not overflow or underflow, the returned value is exact and
independent of the current rounding direction mode.
-
-
-
-[<a name="#p519" href="p519">page 519</a>] (<a href="#Contents">Contents</a>)
+[<a name="p519" href="#p519">page 519</a>] (<a href="#Contents">Contents</a>)
<a name="F.10.4" href="#F.10.4"><b> F.10.4 Power and absolute value functions</b></a>
<a name="F.10.4.1" href="#F.10.4.1"><b> F.10.4.1 The cbrt functions</b></a>
-- pow(x, +(inf)) returns +0 for | x | < 1.
-- pow(x, +(inf)) returns +(inf) for | x | > 1.
-
-[<a name="#p520" href="p520">page 520</a>] (<a href="#Contents">Contents</a>)
+[<a name="p520" href="#p520">page 520</a>] (<a href="#Contents">Contents</a>)
-- pow(-(inf), y) returns -0 for y an odd integer < 0.
-- pow(-(inf), y) returns +0 for y < 0 and not an odd integer.
-- tgamma(-(inf)) returns a NaN and raises the ''invalid'' floating-point exception.
-- tgamma(+(inf)) returns +(inf).
-
-
-[<a name="#p521" href="p521">page 521</a>] (<a href="#Contents">Contents</a>)
+[<a name="p521" href="#p521">page 521</a>] (<a href="#Contents">Contents</a>)
<a name="F.10.6" href="#F.10.6"><b> F.10.6 Nearest integer functions</b></a>
<a name="F.10.6.1" href="#F.10.6.1"><b> F.10.6.1 The ceil functions</b></a>
-- nearbyint((+-)0) returns (+-)0 (for all rounding directions).
-- nearbyint((+-)(inf)) returns (+-)(inf) (for all rounding directions).
-
-
-[<a name="#p522" href="p522">page 522</a>] (<a href="#Contents">Contents</a>)
+[<a name="p522" href="#p522">page 522</a>] (<a href="#Contents">Contents</a>)
<a name="F.10.6.4" href="#F.10.6.4"><b> F.10.6.4 The rint functions</b></a>
1 The rint functions differ from the nearbyint functions only in that they do raise the
The round functions may, but are not required to, raise the ''inexact'' floating-point
exception for finite non-integer numeric arguments, as this implementation does.
-
-
-
-[<a name="#p523" href="p523">page 523</a>] (<a href="#Contents">Contents</a>)
+[<a name="p523" href="#p523">page 523</a>] (<a href="#Contents">Contents</a>)
<a name="F.10.6.7" href="#F.10.6.7"><b> F.10.6.7 The lround and llround functions</b></a>
1 The lround and llround functions differ from the lrint and llrint functions
return copysign(result, x);
}
-
-
-
-[<a name="#p524" href="p524">page 524</a>] (<a href="#Contents">Contents</a>)
+[<a name="p524" href="#p524">page 524</a>] (<a href="#Contents">Contents</a>)
<a name="F.10.7.2" href="#F.10.7.2"><b> F.10.7.2 The remainder functions</b></a>
1 The remainder functions are fully specified as a basic arithmetic operation in
2 Even though underflow or overflow can occur, the returned value is independent of the
current rounding direction mode.
-
-
-
-[<a name="#p525" href="p525">page 525</a>] (<a href="#Contents">Contents</a>)
+[<a name="p525" href="#p525">page 525</a>] (<a href="#Contents">Contents</a>)
<a name="F.10.9" href="#F.10.9"><b> F.10.9 Maximum, minimum, and positive difference functions</b></a>
<a name="F.10.9.1" href="#F.10.9.1"><b> F.10.9.1 The fdim functions</b></a>
1 If just one argument is a NaN, the fmax functions return the other argument (if both
arguments are NaNs, the functions return a NaN).
2 The returned value is exact and is independent of the current rounding direction mode.
-3 The body of the fmax function might be361)
+3 The body of the fmax function might be<sup><a href="#note361"><b>361)</b></a></sup>
{ return (isgreaterequal(x, y) ||
isnan(y)) ? x : y; }
<a name="F.10.9.3" href="#F.10.9.3"><b> F.10.9.3 The fmin functions</b></a>
- 361) Ideally, fmax would be sensitive to the sign of zero, for example fmax(-0.0, +0.0) would
+ <sup><a name="note361" href="#note361"><b>361)</b></a></sup> Ideally, fmax would be sensitive to the sign of zero, for example fmax(-0.0, +0.0) would
return +0; however, implementation in software might be impractical.
-[<a name="
#p526" href="p526">page 526</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p526" href="#p526">page 526</a>] (<a href="#Contents">Contents</a>)
<a name="F.10.11" href="#F.10.11"><b> F.10.11 Comparison macros</b></a>
1 Relational operators and their corresponding comparison macros (<a href="#7.12.14">7.12.14</a>) produce
characterized by FLT_EVAL_METHOD equal to 1 or 2 (<a href="#5.2.4.2.2">5.2.4.2.2</a>), do not convert
operands of relational operators to their semantic types.
-
-
-
-[<a name="#p527" href="p527">page 527</a>] (<a href="#Contents">Contents</a>)
+[<a name="p527" href="#p527">page 527</a>] (<a href="#Contents">Contents</a>)
<a name="G" href="#G"><b> Annex G</b></a>
(normative)
<a name="G.1" href="#G.1"><b> G.1 Introduction</b></a>
1 This annex supplements <a href="#F">annex F</a> to specify complex arithmetic for compatibility with
IEC 60559 real floating-point arithmetic. An implementation that defines *
- __STDC_IEC_559_COMPLEX__ shall conform to the specifications in this annex.362)
+ __STDC_IEC_559_COMPLEX__ shall conform to the specifications in this annex.<sup><a href="#note362"><b>362)</b></a></sup>
<a name="G.2" href="#G.2"><b> G.2 Types</b></a>
1 There is a new keyword _Imaginary, which is used to specify imaginary types. It is
used as a type specifier within declaration specifiers in the same way as _Complex is
- 362) Implementations that do not define __STDC_IEC_559_COMPLEX__ are not required to conform
+ <sup><a name="note362" href="#note362"><b>362)</b></a></sup> Implementations that do not define __STDC_IEC_559_COMPLEX__ are not required to conform
to these specifications.
-[<a name="
#p528" href="p528">page 528</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p528" href="#p528">page 528</a>] (<a href="#Contents">Contents</a>)
<a name="G.4" href="#G.4"><b> G.4 Conversions</b></a>
<a name="G.4.1" href="#G.4.1"><b> G.4.1 Imaginary types</b></a>
1 Conversions among imaginary types follow rules analogous to those for real floating
types.
<a name="G.4.2" href="#G.4.2"><b> G.4.2 Real and imaginary</b></a>
-1 When a value of imaginary type is converted to a real type other than _Bool,363) the
+1 When a value of imaginary type is converted to a real type other than _Bool,<sup><a href="#note363"><b>363)</b></a></sup> the
result is a positive zero.
2 When a value of real type is converted to an imaginary type, the result is a positive
imaginary zero.
-
363) See <a href="#6.3.1.2">6.3.1.2</a>.
+
<sup><a name="note363" href="#note363"><b>363)</b></a></sup> See <a href="#6.3.1.2">6.3.1.2</a>.
-[<a name="
#p529" href="p529">page 529</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p529" href="#p529">page 529</a>] (<a href="#Contents">Contents</a>)
<a name="G.5.1" href="#G.5.1"><b> G.5.1 Multiplicative operators</b></a>
- Semantics
+<b> Semantics</b>
1 If one operand has real type and the other operand has imaginary type, then the result has
imaginary type. If both operands have imaginary type, then the result has real type. (If
either operand has complex type, then the result has complex type.)
x + iy (x/u) + i(y/u) (y/v) + i(-x/v)
4 The * and / operators satisfy the following infinity properties for all real, imaginary, and
- complex operands:364)
+ complex operands:<sup><a href="#note364"><b>364)</b></a></sup>
-- if one operand is an infinity and the other operand is a nonzero finite number or an
infinity, then the result of the * operator is an infinity;
-- if the first operand is an infinity and the second operand is a finite number, then the
- 364) These properties are already implied for those cases covered in the tables, but are required for all cases
+ <sup><a name="note364" href="#note364"><b>364)</b></a></sup> These properties are already implied for those cases covered in the tables, but are required for all cases
(at least where the state for CX_LIMITED_RANGE is ''off'').
-[<a name="
#p530" href="p530">page 530</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p530" href="#p530">page 530</a>] (<a href="#Contents">Contents</a>)
-- if the first operand is a nonzero finite number or an infinity and the second operand is
a zero, then the result of the / operator is an infinity.
int recalc = 0;
if ( isinf(a) || isinf(b) ) { // z is infinite
/* "Box" the infinity and change NaNs in the other factor to 0 */
- a = copysign(isinf(a) ? <a href="#1.0">1.0</a> : 0.0, a);
- b = copysign(isinf(b) ? <a href="#1.0">1.0</a> : 0.0, b);
+ a = copysign(isinf(a) ? 1.0 : 0.0, a);
+ b = copysign(isinf(b) ? 1.0 : 0.0, b);
if (isnan(c)) c = copysign(0.0, c);
if (isnan(d)) d = copysign(0.0, d);
recalc = 1;
}
if ( isinf(c) || isinf(d) ) { // w is infinite
/* "Box" the infinity and change NaNs in the other factor to 0 */
- c = copysign(isinf(c) ? <a href="#1.0">1.0</a> : 0.0, c);
- d = copysign(isinf(d) ? <a href="#1.0">1.0</a> : 0.0, d);
+ c = copysign(isinf(c) ? 1.0 : 0.0, c);
+ d = copysign(isinf(d) ? 1.0 : 0.0, d);
if (isnan(a)) a = copysign(0.0, a);
if (isnan(b)) b = copysign(0.0, b);
recalc = 1;
}
if (recalc) {
-[<a name="
#p531" href="p531">page 531</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p531" href="#p531">page 531</a>] (<a href="#Contents">Contents</a>)
x = INFINITY * ( a * c - b * d );
y = INFINITY * ( a * d + b * c );
}
else if ((isinf(a) || isinf(b)) &&
isfinite(c) && isfinite(d)) {
- a = copysign(isinf(a) ? <a href="#1.0">1.0</a> : 0.0, a);
- b = copysign(isinf(b) ? <a href="#1.0">1.0</a> : 0.0, b);
+ a = copysign(isinf(a) ? 1.0 : 0.0, a);
+ b = copysign(isinf(b) ? 1.0 : 0.0, b);
x = INFINITY * ( a * c + b * d );
y = INFINITY * ( b * c - a * d );
}
else if (isinf(logbw) &&
isfinite(a) && isfinite(b)) {
- c = copysign(isinf(c) ? <a href="#1.0">1.0</a> : 0.0, c);
- d = copysign(isinf(d) ? <a href="#1.0">1.0</a> : 0.0, d);
+ c = copysign(isinf(c) ? 1.0 : 0.0, c);
+ d = copysign(isinf(d) ? 1.0 : 0.0, d);
x = 0.0 * ( a * c + b * d );
y = 0.0 * ( b * c - a * d );
-[<a name="
#p532" href="p532">page 532</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p532" href="#p532">page 532</a>] (<a href="#Contents">Contents</a>)
}
}
with division, provides better roundoff characteristics.
<a name="G.5.2" href="#G.5.2"><b> G.5.2 Additive operators</b></a>
- Semantics
+<b> Semantics</b>
1 If both operands have imaginary type, then the result has imaginary type. (If one operand
has real type and the other operand has imaginary type, or if either operand has complex
type, then the result has complex type.)
particularly suited to IEC 60559 implementations. For families of functions, the
specifications apply to all of the functions even though only the principal function is
-[<a name="
#p533" href="p533">page 533</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p533" href="#p533">page 533</a>] (<a href="#Contents">Contents</a>)
shown. Unless otherwise specified, where the symbol ''(+-)'' occurs in both an argument
and the result, the result has the same sign as the argument.
3 The functions are continuous onto both sides of their branch cuts, taking into account the
- sign of zero. For example, csqrt(-2 (+-) i0) = (+-)isqrt:2. -
+ sign of zero. For example, csqrt(-2 (+-) i0) = (+-)i(sqrt)2. -
4 Since complex and imaginary values are composed of real values, each function may be
regarded as computing real values from real values. Except as noted, the functions treat
real infinities, NaNs, signed zeros, subnormals, and the floating-point exception flags in a
- manner consistent with the specifications for real functions in F.10.365)
+ manner consistent with the specifications for real functions in F.10.<sup><a href="#note365"><b>365)</b></a></sup>
5 The functions cimag, conj, cproj, and creal are fully specified for all
implementations, including IEC 60559 ones, in <a href="#7.3.9">7.3.9</a>. These functions raise no floating-
point exceptions.
-
365) As noted in <a href="#G.3">G.3</a>, a complex value with at least one infinite part is regarded as an infinity even if its
+
<sup><a name="note365" href="#note365"><b>365)</b></a></sup> As noted in <a href="#G.3">G.3</a>, a complex value with at least one infinite part is regarded as an infinity even if its
other part is a NaN.
-[<a name="
#p534" href="p534">page 534</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p534" href="#p534">page 534</a>] (<a href="#Contents">Contents</a>)
<a name="G.6.1" href="#G.6.1"><b> G.6.1 Trigonometric functions</b></a>
<a name="G.6.1.1" href="#G.6.1.1"><b> G.6.1.1 The cacos functions</b></a>
-- cacosh(+(inf) + i (inf)) returns +(inf) + ipi /4.
-- cacosh((+-)(inf) + iNaN) returns +(inf) + iNaN.
-
-[<a name="#p535" href="p535">page 535</a>] (<a href="#Contents">Contents</a>)
+[<a name="p535" href="#p535">page 535</a>] (<a href="#Contents">Contents</a>)
-- cacosh(NaN + iy) returns NaN + iNaN and optionally raises the ''invalid''
floating-point exception, for finite y.
-- catanh(+(inf) + i (inf)) returns +0 + ipi /2.
-- catanh(+(inf) + iNaN) returns +0 + iNaN.
-[<a name="
#p536" href="p536">page 536</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p536" href="#p536">page 536</a>] (<a href="#Contents">Contents</a>)
-- catanh(NaN + iy) returns NaN + iNaN and optionally raises the ''invalid''
floating-point exception, for finite y.
unspecified) and raises the ''invalid'' floating-point exception.
-- csinh(+0 + iNaN) returns (+-)0 + iNaN (where the sign of the real part of the result is
unspecified).
-[<a name="#p537" href="p537">page 537</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p537" href="#p537">page 537</a>] (<a href="#Contents">Contents</a>)
-- csinh(x + i (inf)) returns NaN + iNaN and raises the ''invalid'' floating-point
exception, for positive finite x.
point exception, for all nonzero numbers y.
-- ctanh(NaN + iNaN) returns NaN + iNaN.
-
-
-
-[<a name="#p538" href="p538">page 538</a>] (<a href="#Contents">Contents</a>)
+[<a name="p538" href="#p538">page 538</a>] (<a href="#Contents">Contents</a>)
<a name="G.6.3" href="#G.6.3"><b> G.6.3 Exponential and logarithmic functions</b></a>
<a name="G.6.3.1" href="#G.6.3.1"><b> G.6.3.1 The cexp functions</b></a>
-- clog(x + iNaN) returns NaN + iNaN and optionally raises the ''invalid'' floating-
point exception, for finite x.
-[<a name="
#p539" href="p539">page 539</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p539" href="#p539">page 539</a>] (<a href="#Contents">Contents</a>)
-- clog(-(inf) + iy) returns +(inf) + ipi , for finite positive-signed y.
-- clog(+(inf) + iy) returns +(inf) + i0, for finite positive-signed y.
<a name="G.6.4" href="#G.6.4"><b> G.6.4 Power and absolute-value functions</b></a>
<a name="G.6.4.1" href="#G.6.4.1"><b> G.6.4.1 The cpow functions</b></a>
1 The cpow functions raise floating-point exceptions if appropriate for the calculation of
- the parts of the result, and may also raise spurious floating-point exceptions.366)
+ the parts of the result, and may also raise spurious floating-point exceptions.<sup><a href="#note366"><b>366)</b></a></sup>
<a name="G.6.4.2" href="#G.6.4.2"><b> G.6.4.2 The csqrt functions</b></a>
1 -- csqrt(conj(z)) = conj(csqrt(z)).
-- csqrt((+-)0 + i0) returns +0 + i0.
- 366) This allows cpow( z , c ) to be implemented as cexp(c clog( z )) without precluding
+ <sup><a name="note366" href="#note366"><b>366)</b></a></sup> This allows cpow( z , c ) to be implemented as cexp(c clog( z )) without precluding
implementations that treat special cases more carefully.
-[<a name="
#p540" href="p540">page 540</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p540" href="#p540">page 540</a>] (<a href="#Contents">Contents</a>)
<a name="G.7" href="#G.7"><b> G.7 Type-generic math <tgmath.h></b></a>
1 Type-generic macros that accept complex arguments also accept imaginary arguments. If
asinh(iy) = i asin(y)
atanh(iy) = i atan(y)
-
-
-
-[<a name="#p541" href="p541">page 541</a>] (<a href="#Contents">Contents</a>)
+[<a name="p541" href="#p541">page 541</a>] (<a href="#Contents">Contents</a>)
<a name="H" href="#H"><b> Annex H</b></a>
(informative)
3 The parameter ''bounded'' is always true, and is not provided. The parameter ''minint''
is always 0 for the unsigned types, and is not provided for those types.
-
-
-
-[<a name="#p542" href="p542">page 542</a>] (<a href="#Contents">Contents</a>)
+[<a name="p542" href="#p542">page 542</a>] (<a href="#Contents">Contents</a>)
<a name="H.2.2.1" href="#H.2.2.1"><b> H.2.2.1 Integer operations</b></a>
1 The integer operations on integer types are the following:
emin FLT_MIN_EXP, DBL_MIN_EXP, LDBL_MIN_EXP
2 The derived constants for the floating point types are accessed by the following:
-
-[<a name="#p543" href="p543">page 543</a>] (<a href="#Contents">Contents</a>)
+[<a name="p543" href="#p543">page 543</a>] (<a href="#Contents">Contents</a>)
fmax FLT_MAX, DBL_MAX, LDBL_MAX
fminN FLT_MIN, DBL_MIN, LDBL_MIN
divF x / y
negF -x
absF fabsf(x), fabs(x), fabsl(x)
- exponentF 1.f+logbf(x), <a href="#1.0">1.0</a>+logb(x), 1.L+logbl(x)
+ exponentF 1.f+logbf(x), 1.0+logb(x), 1.L+logbl(x)
scaleF scalbnf(x, n), scalbn(x, n), scalbnl(x, n),
scalblnf(x, li), scalbln(x, li), scalblnl(x, li)
intpartF modff(x, &y), modf(x, &y), modfl(x, &y)
2 The FLT_ROUNDS parameter can be used to indicate the LIA-1 rounding styles:
truncate FLT_ROUNDS == 0
-
-[<a name="#p544" href="p544">page 544</a>] (<a href="#Contents">Contents</a>)
+[<a name="p544" href="#p544">page 544</a>] (<a href="#Contents">Contents</a>)
nearest FLT_ROUNDS == 1
other FLT_ROUNDS != 0 && FLT_ROUNDS != 1
in all relevant LIA-1 operations, not just addition as in C.
<a name="H.2.4" href="#H.2.4"><b> H.2.4 Type conversions</b></a>
1 The LIA-1 type conversions are the following type casts:
- cvtI' (->) I (int)i, (long int)i, (long long int)i,
+ cvtI' -> I (int)i, (long int)i, (long long int)i,
(unsigned int)i, (unsigned long int)i,
(unsigned long long int)i
- cvtF (->) I (int)x, (long int)x, (long long int)x,
+ cvtF -> I (int)x, (long int)x, (long long int)x,
(unsigned int)x, (unsigned long int)x,
(unsigned long long int)x
- cvtI (->) F (float)i, (double)i, (long double)i
- cvtF' (->) F (float)x, (double)x, (long double)x
+ cvtI -> F (float)i, (double)i, (long double)i
+ cvtF' -> F (float)x, (double)x, (long double)x
2 In the above conversions from floating to integer, the use of (cast)x can be replaced with
(cast)round(x), (cast)rint(x), (cast)nearbyint(x), (cast)trunc(x),
(cast)ceil(x), or (cast)floor(x). In addition, C's floating-point to integer
5 C's conversions (casts) from integer to floating-point can meet LIA-1 requirements if an
implementation uses round-to-nearest.
-
-
-
-[<a name="#p545" href="p545">page 545</a>] (<a href="#Contents">Contents</a>)
+[<a name="p545" href="#p545">page 545</a>] (<a href="#Contents">Contents</a>)
<a name="H.3" href="#H.3"><b> H.3 Notification</b></a>
1 Notification is the process by which a user or program is informed that an exceptional
where i is an expression of type int representing a subset of the LIA-1 indicators.
4 C allows an implementation to provide the following LIA-1 required behavior: at
program termination if any indicator is set the implementation shall send an unambiguous
-[<a name="#p546" href="p546">page 546</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p546" href="#p546">page 546</a>] (<a href="#Contents">Contents</a>)
and ''hard to ignore'' message (see LIA-1 subclause <a href="#6.1.2">6.1.2</a>)
5 LIA-1 does not make the distinction between floating-point and integer for ''undefined''.
allows trap-and-terminate (either default implementation behavior or user replacement for
it) or trap-and-resume, at the programmer's option.
-
-
-
-[<a name="#p547" href="p547">page 547</a>] (<a href="#Contents">Contents</a>)
+[<a name="p547" href="#p547">page 547</a>] (<a href="#Contents">Contents</a>)
<a name="I" href="#I"><b> Annex I</b></a>
(informative)
-- A statement with no apparent effect is encountered (<a href="#6.8">6.8</a>).
-- A constant expression is used as the controlling expression of a selection statement
(<a href="#6.8.4">6.8.4</a>).
-[<a name="#p548" href="p548">page 548</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p548" href="#p548">page 548</a>] (<a href="#Contents">Contents</a>)
-- An incorrectly formed preprocessing group is encountered while skipping a
preprocessing group (<a href="#6.10.1">6.10.1</a>).
-- An unrecognized #pragma directive is encountered (<a href="#6.10.6">6.10.6</a>).
-
-
-
-[<a name="#p549" href="p549">page 549</a>] (<a href="#Contents">Contents</a>)
+[<a name="p549" href="#p549">page 549</a>] (<a href="#Contents">Contents</a>)
<a name="J" href="#J"><b> Annex J</b></a>
(informative)
-- Whether two string literals result in distinct arrays (<a href="#6.4.5">6.4.5</a>).
-- The order in which subexpressions are evaluated and the order in which side effects
take place, except as specified for the function-call (), &&, ||, ? :, and comma
-[<a name="#p550" href="p550">page 550</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p550" href="#p550">page 550</a>] (<a href="#Contents">Contents</a>)
operators (<a href="#6.5">6.5</a>).
-- The order in which the function designator, arguments, and subexpressions within the
range of the return type (<a href="#7.12.6.5">7.12.6.5</a>, <a href="#F.10.3.5">F.10.3.5</a>).
-- The result of rounding when the value is out of range (<a href="#7.12.9.5">7.12.9.5</a>, <a href="#7.12.9.7">7.12.9.7</a>, <a href="#F.10.6.5">F.10.6.5</a>).
-
-[<a name="#p551" href="p551">page 551</a>] (<a href="#Contents">Contents</a>)
+[<a name="p551" href="#p551">page 551</a>] (<a href="#Contents">Contents</a>)
-- The value stored by the remquo functions in the object pointed to by quo when y is
zero (<a href="#7.12.10.3">7.12.10.3</a>).
-- The resulting value when the ''invalid'' floating-point exception is raised during
IEC 60559 floating to integer conversion (<a href="#F.4">F.4</a>).
-
-
-[<a name="#p552" href="p552">page 552</a>] (<a href="#Contents">Contents</a>)
+[<a name="p552" href="#p552">page 552</a>] (<a href="#Contents">Contents</a>)
-- Whether conversion of non-integer IEC 60559 floating values to integer raises the
''inexact'' floating-point exception (<a href="#F.4">F.4</a>).
(<a href="#6.2.2">6.2.2</a>).
-- An object is referred to outside of its lifetime (<a href="#6.2.4">6.2.4</a>).
-
-
-[<a name="#p553" href="p553">page 553</a>] (<a href="#Contents">Contents</a>)
+[<a name="p553" href="#p553">page 553</a>] (<a href="#Contents">Contents</a>)
-- The value of a pointer to an object whose lifetime has ended is used (<a href="#6.2.4">6.2.4</a>).
-- The value of an object with automatic storage duration is used while it is
-- A pointer is used to call a function whose type is not compatible with the referenced
type (<a href="#6.3.2.3">6.3.2.3</a>).
-
-
-[<a name="#p554" href="p554">page 554</a>] (<a href="#Contents">Contents</a>)
+[<a name="p554" href="#p554">page 554</a>] (<a href="#Contents">Contents</a>)
-- An unmatched ' or " character is encountered on a logical source line during
tokenization (<a href="#6.4">6.4</a>).
-- A member of an atomic structure or union is accessed (<a href="#6.5.2.3">6.5.2.3</a>).
-- The operand of the unary * operator has an invalid value (<a href="#6.5.3.2">6.5.3.2</a>).
-
-[<a name="#p555" href="p555">page 555</a>] (<a href="#Contents">Contents</a>)
+[<a name="p555" href="#p555">page 555</a>] (<a href="#Contents">Contents</a>)
-- A pointer is converted to other than an integer or pointer type (<a href="#6.5.4">6.5.4</a>).
-- The value of the second operand of the / or % operator is zero (<a href="#6.5.5">6.5.5</a>).
are not integer constants, floating constants, enumeration constants, character
constants, or sizeof expressions; or contains casts (outside operands to sizeof
-[<a name="
#p556" href="p556">page 556</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p556" href="#p556">page 556</a>] (<a href="#Contents">Contents</a>)
operators) other than conversions of arithmetic types to arithmetic types (<a href="#6.6">6.6</a>).
-- The value of an object is accessed by an array-subscript [], member-access . or ->,
-- The definition of an object has an alignment specifier and another declaration of that
object has a different alignment specifier (<a href="#6.7.5">6.7.5</a>).
-
-[<a name="#p557" href="p557">page 557</a>] (<a href="#Contents">Contents</a>)
+[<a name="p557" href="#p557">page 557</a>] (<a href="#Contents">Contents</a>)
-- Declarations of an object in different translation units have different alignment
specifiers (<a href="#6.7.5">6.7.5</a>).
-- A function that accepts a variable number of arguments is defined without a
parameter type list that ends with the ellipsis notation (<a href="#6.9.1">6.9.1</a>).
-[<a name="
#p558" href="p558">page 558</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p558" href="#p558">page 558</a>] (<a href="#Contents">Contents</a>)
-- The } that terminates a function is reached, and the value of the function call is used
by the caller (<a href="#6.9.1">6.9.1</a>).
some standard header is used before any header that declares or defines it is included
(<a href="#7.1.2">7.1.2</a>).
-[<a name="
#p559" href="p559">page 559</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p559" href="#p559">page 559</a>] (<a href="#Contents">Contents</a>)
-- A standard header is included while a macro is defined with the same name as a
keyword (<a href="#7.1.2">7.1.2</a>).
-- The value of the result of an integer arithmetic or conversion function cannot be
represented (<a href="#7.8.2.1">7.8.2.1</a>, <a href="#7.8.2.2">7.8.2.2</a>, <a href="#7.8.2.3">7.8.2.3</a>, <a href="#7.8.2.4">7.8.2.4</a>, <a href="#7.22.6.1">7.22.6.1</a>, <a href="#7.22.6.2">7.22.6.2</a>, <a href="#7.22.1">7.22.1</a>).
-[<a name="
#p560" href="p560">page 560</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p560" href="#p560">page 560</a>] (<a href="#Contents">Contents</a>)
-- The program modifies the string pointed to by the value returned by the setlocale
function (<a href="#7.11.1.1">7.11.1.1</a>).
arguments other than through a properly declared and initialized va_list object, or
before the va_start macro is invoked (<a href="#7.16">7.16</a>, <a href="#7.16.1.1">7.16.1.1</a>, <a href="#7.16.1.4">7.16.1.4</a>).
-[<a name="
#p561" href="p561">page 561</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p561" href="#p561">page 561</a>] (<a href="#Contents">Contents</a>)
-- The macro va_arg is invoked using the parameter ap that was passed to a function
that invoked the macro va_arg with the same parameter (<a href="#7.16">7.16</a>).
exactly match one of the specified character sequences (<a href="#7.21.5.3">7.21.5.3</a>).
-- An output operation on an update stream is followed by an input operation without an
intervening call to the fflush function or a file positioning function, or an input
-[<a name="#p562" href="p562">page 562</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p562" href="#p562">page 562</a>] (<a href="#Contents">Contents</a>)
operation on an update stream is followed by an output operation with an intervening
call to a file positioning function (<a href="#7.21.5.3">7.21.5.3</a>).
-- The number of characters transmitted by a formatted output function is greater than
INT_MAX (<a href="#7.21.6.1">7.21.6.1</a>, <a href="#7.21.6.3">7.21.6.3</a>, <a href="#7.21.6.8">7.21.6.8</a>, <a href="#7.21.6.10">7.21.6.10</a>).
-
-[<a name="#p563" href="p563">page 563</a>] (<a href="#Contents">Contents</a>)
+[<a name="p563" href="#p563">page 563</a>] (<a href="#Contents">Contents</a>)
-- The result of a conversion by one of the formatted input functions cannot be
represented in the corresponding object, or the receiving object does not have an
-- The value of a pointer that refers to space deallocated by a call to the free or
realloc function is used (<a href="#7.22.3">7.22.3</a>).
-
-[<a name="#p564" href="p564">page 564</a>] (<a href="#Contents">Contents</a>)
+[<a name="p564" href="#p564">page 564</a>] (<a href="#Contents">Contents</a>)
-- The alignment requested of the aligned_alloc function is not valid or not
supported by the implementation, or the size requested is not an integral multiple of
too small to hold the entire null-terminated result (<a href="#7.23.4.5">7.23.4.5</a>, <a href="#7.26.3.5">7.26.3.5</a>, <a href="#7.28.4.4.4">7.28.4.4.4</a>,
<a href="#7.28.5.1">7.28.5.1</a>).
-[<a name="
#p565" href="p565">page 565</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p565" href="#p565">page 565</a>] (<a href="#Contents">Contents</a>)
-- The first argument in the very first call to the strtok or wcstok is a null pointer
(<a href="#7.23.5.8">7.23.5.8</a>, <a href="#7.28.4.5.7">7.28.4.5.7</a>).
1 A conforming implementation is required to document its choice of behavior in each of
the areas listed in this subclause. The following are implementation-defined:
-
-
-
-[<a name="#p566" href="p566">page 566</a>] (<a href="#Contents">Contents</a>)
+[<a name="p566" href="#p566">page 566</a>] (<a href="#Contents">Contents</a>)
<a name="J.3.1" href="#J.3.1"><b> J.3.1 Translation</b></a>
1 -- How a diagnostic is identified (<a href="#3.10">3.10</a>, <a href="#5.1.1.3">5.1.1.3</a>).
correspondence to universal character names (<a href="#6.4.2">6.4.2</a>).
-- The number of significant initial characters in an identifier (<a href="#5.2.4.1">5.2.4.1</a>, <a href="#6.4.2">6.4.2</a>).
-
-
-
-[<a name="#p567" href="p567">page 567</a>] (<a href="#Contents">Contents</a>)
+[<a name="p567" href="#p567">page 567</a>] (<a href="#Contents">Contents</a>)
<a name="J.3.4" href="#J.3.4"><b> J.3.4 Characters</b></a>
1 -- The number of bits in a byte (<a href="#3.6">3.6</a>).
corresponding standard encoding macro (__STDC_ISO_10646__,
__STDC_UTF_16__, or __STDC_UTF_32__) is not defined (<a href="#6.10.8.2">6.10.8.2</a>).
-
-
-
-[<a name="#p568" href="p568">page 568</a>] (<a href="#Contents">Contents</a>)
+[<a name="p568" href="#p568">page 568</a>] (<a href="#Contents">Contents</a>)
<a name="J.3.5" href="#J.3.5"><b> J.3.5 Integers</b></a>
1 -- Any extended integer types that exist in the implementation (<a href="#6.2.5">6.2.5</a>).
classifications, and their macro names (<a href="#7.6">7.6</a>, <a href="#7.12">7.12</a>).
-- The default state for the FP_CONTRACT pragma (<a href="#7.12.2">7.12.2</a>).
-
-[<a name="#p569" href="p569">page 569</a>] (<a href="#Contents">Contents</a>)
+[<a name="p569" href="#p569">page 569</a>] (<a href="#Contents">Contents</a>)
<a name="J.3.7" href="#J.3.7"><b> J.3.7 Arrays and pointers</b></a>
1 -- The result of converting a pointer to an integer or vice versa (<a href="#6.3.2.3">6.3.2.3</a>).
-- Whether the value of a single-character character constant in a constant expression
that controls conditional inclusion may have a negative value (<a href="#6.10.1">6.10.1</a>).
-
-[<a name="#p570" href="p570">page 570</a>] (<a href="#Contents">Contents</a>)
+[<a name="p570" href="#p570">page 570</a>] (<a href="#Contents">Contents</a>)
-- The places that are searched for an included < > delimited header, and how the places
are specified or the header is identified (<a href="#6.10.2">6.10.2</a>).
floating-point exception is raised when the integer expression math_errhandling
& MATH_ERREXCEPT is nonzero. (<a href="#7.12.1">7.12.1</a>).
-[<a name="
#p571" href="p571">page 571</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p571" href="#p571">page 571</a>] (<a href="#Contents">Contents</a>)
-- Whether a domain error occurs or zero is returned when an fmod function has a
second argument of zero (<a href="#7.12.10.1">7.12.10.1</a>).
-- Which changes of mode are permitted (if any), and under what circumstances
(<a href="#7.21.5.4">7.21.5.4</a>).
-[<a name="
#p572" href="p572">page 572</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p572" href="#p572">page 572</a>] (<a href="#Contents">Contents</a>)
-- The style used to print an infinity or NaN, and the meaning of any n-char or n-wchar
sequence printed for a NaN (<a href="#7.21.6.1">7.21.6.1</a>, <a href="#7.28.2.1">7.28.2.1</a>).
-- Whether the functions in <a href="#7.12"><math.h></a> honor the rounding direction mode in an
IEC 60559 conformant implementation, unless explicitly specified otherwise (<a href="#F.10">F.10</a>).
-
-
-
-[<a name="#p573" href="p573">page 573</a>] (<a href="#Contents">Contents</a>)
+[<a name="p573" href="#p573">page 573</a>] (<a href="#Contents">Contents</a>)
<a name="J.3.13" href="#J.3.13"><b> J.3.13 Architecture</b></a>
1 -- The values or expressions assigned to the macros specified in the headers
<a href="#7.28.4.1">7.28.4.1</a>).
-- The collation sequence of the execution character set (<a href="#7.23.4.3">7.23.4.3</a>, <a href="#7.28.4.4.2">7.28.4.4.2</a>).
-
-[<a name="#p574" href="p574">page 574</a>] (<a href="#Contents">Contents</a>)
+[<a name="p574" href="#p574">page 574</a>] (<a href="#Contents">Contents</a>)
-- The contents of the error message strings set up by the strerror function
(<a href="#7.23.6.2">7.23.6.2</a>).
1 String literals are modifiable (in which case, identical string literals should denote distinct
objects) (<a href="#6.4.5">6.4.5</a>).
-
-
-
-[<a name="#p575" href="p575">page 575</a>] (<a href="#Contents">Contents</a>)
+[<a name="p575" href="#p575">page 575</a>] (<a href="#Contents">Contents</a>)
<a name="J.5.6" href="#J.5.6"><b> J.5.6 Other arithmetic types</b></a>
1 Additional arithmetic types, such as __int128 or double double, and their
execution environments, are defined by the implementation before translation begins
(<a href="#6.10.8">6.10.8</a>).
-
-
-
-[<a name="#p576" href="p576">page 576</a>] (<a href="#Contents">Contents</a>)
+[<a name="p576" href="#p576">page 576</a>] (<a href="#Contents">Contents</a>)
<a name="J.5.13" href="#J.5.13"><b> J.5.13 Floating-point status flags</b></a>
1 If any floating-point status flags are set on normal termination after all calls to functions
instead of, or in addition to, setting errno or raising floating-point exceptions (<a href="#7.3">7.3</a>,
<a name="7.12)" href="#7.12)"><b> 7.12).</b></a>
-
-
-
-[<a name="#p577" href="p577">page 577</a>] (<a href="#Contents">Contents</a>)
+[<a name="p577" href="#p577">page 577</a>] (<a href="#Contents">Contents</a>)
<a name="K" href="#K"><b> Annex K</b></a>
(normative)
function. Such functions can be troublesome since a previously returned result can
change if the function is called again, perhaps by another thread.
-
-
-
-[<a name="#p578" href="p578">page 578</a>] (<a href="#Contents">Contents</a>)
+[<a name="p578" href="#p578">page 578</a>] (<a href="#Contents">Contents</a>)
<a name="K.2" href="#K.2"><b> K.2 Scope</b></a>
1 This annex specifies a series of optional extensions that can be useful in the mitigation of
security vulnerabilities in programs, and comprise new functions, macros, and types
declared or defined in existing standard headers.
2 An implementation that defines __STDC_LIB_EXT1__ shall conform to the
- specifications in this annex.367)
+ specifications in this annex.<sup><a href="#note367"><b>367)</b></a></sup>
3 Subclause <a href="#K.3">K.3</a> should be read as if it were merged into the parallel structure of named
subclauses of clause 7.
<a name="K.3" href="#K.3"><b> K.3 Library</b></a>
2 The functions, macros, and types declared or defined in <a href="#K.3">K.3</a> and its subclauses are
declared and defined by their respective headers if __STDC_WANT_LIB_EXT1__ is
defined as a macro which expands to the integer constant 1 at the point in the source file
- where the appropriate header is first included.368)
+ where the appropriate header is first included.<sup><a href="#note368"><b>368)</b></a></sup>
3 It is implementation-defined whether the functions, macros, and types declared or defined
in <a href="#K.3">K.3</a> and its subclauses are declared or defined by their respective headers if
__STDC_WANT_LIB_EXT1__ is not defined as a macro at the point in the source file
- where the appropriate header is first included.369)
+ where the appropriate header is first included.<sup><a href="#note369"><b>369)</b></a></sup>
4 Within a preprocessing translation unit, __STDC_WANT_LIB_EXT1__ shall be
defined identically for all inclusions of any headers from subclause <a href="#K.3">K.3</a>. If
__STDC_WANT_LIB_EXT1__ is defined differently for any such inclusion, the
implementation shall issue a diagnostic as if a preprocessor error directive were used.
- 367) Implementations that do not define __STDC_LIB_EXT1__ are not required to conform to these
+ <sup><a name="note367" href="#note367"><b>367)</b></a></sup> Implementations that do not define __STDC_LIB_EXT1__ are not required to conform to these
specifications.
- 368) Future revisions of this International Standard may define meanings for other values of
+ <sup><a name="note368" href="#note368"><b>368)</b></a></sup> Future revisions of this International Standard may define meanings for other values of
__STDC_WANT_LIB_EXT1__.
-
369) Subclause <a href="#7.1.3">7.1.3</a> reserves certain names and patterns of names that an implementation may use in
+
<sup><a name="note369" href="#note369"><b>369)</b></a></sup> Subclause <a href="#7.1.3">7.1.3</a> reserves certain names and patterns of names that an implementation may use in
headers. All other names are not reserved, and a conforming implementation is not permitted to use
them. While some of the names defined in <a href="#K.3">K.3</a> and its subclauses are reserved, others are not. If an
unreserved name is defined in a header when __STDC_WANT_LIB_EXT1__ is defined as 0, the
implementation is not conforming.
-[<a name="
#p579" href="p579">page 579</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p579" href="#p579">page 579</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.1.2" href="#K.3.1.2"><b> K.3.1.2 Reserved identifiers</b></a>
1 Each macro name in any of the following subclauses is reserved for use as specified if it
<a name="K.3.1.4" href="#K.3.1.4"><b> K.3.1.4 Runtime-constraint violations</b></a>
1 Most functions in this annex include as part of their specification a list of runtime-
constraints. These runtime-constraints are requirements on the program using the
- library.370)
+ library.<sup><a href="#note370"><b>370)</b></a></sup>
2 Implementations shall verify that the runtime-constraints for a function are not violated
by the program. If a runtime-constraint is violated, the implementation shall call the
currently registered runtime-constraint handler (see set_constraint_handler_s
- 370) Although runtime-constraints replace many cases of undefined behavior, undefined behavior still
+ <sup><a name="note370" href="#note370"><b>370)</b></a></sup> Although runtime-constraints replace many cases of undefined behavior, undefined behavior still
exists in this annex. Implementations are free to detect any case of undefined behavior and treat it as a
runtime-constraint violation by calling the runtime-constraint handler. This license comes directly
from the definition of undefined behavior.
-[<a name="
#p580" href="p580">page 580</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p580" href="#p580">page 580</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.2" href="#K.3.2"><b> K.3.2 Errors <errno.h></b></a>
1 The header <a href="#7.5"><errno.h></a> defines a type.
2 The type is
errno_t
- which is type int.371)
+ which is type int.<sup><a href="#note371"><b>371)</b></a></sup>
<a name="K.3.3" href="#K.3.3"><b> K.3.3 Common definitions <stddef.h></b></a>
1 The header <a href="#7.19"><stddef.h></a> defines a type.
2 The type is
rsize_t
- which is the type size_t.372)
+ which is the type size_t.<sup><a href="#note372"><b>372)</b></a></sup>
<a name="K.3.4" href="#K.3.4"><b> K.3.4 Integer types <stdint.h></b></a>
1 The header <a href="#7.20"><stdint.h></a> defines a macro.
2 The macro is
RSIZE_MAX
- which expands to a value373) of type size_t. Functions that have parameters of type
+ which expands to a value<sup><a href="#note373"><b>373)</b></a></sup> of type size_t. Functions that have parameters of type
rsize_t consider it a runtime-constraint violation if the values of those parameters are
greater than RSIZE_MAX.
Recommended practice
some legitimate, but very large, objects. Implementations targeting machines with small
address spaces may wish to define RSIZE_MAX as SIZE_MAX, which means that there
- 371) As a matter of programming style, errno_t may be used as the type of something that deals only
+ <sup><a name="note371" href="#note371"><b>371)</b></a></sup> As a matter of programming style, errno_t may be used as the type of something that deals only
with the values that might be found in errno. For example, a function which returns the value of
errno might be declared as having the return type errno_t.
-
372) See the description of the RSIZE_MAX macro in <a href="#7.20"><stdint.h></a>.
- 373) The macro RSIZE_MAX need not expand to a constant expression.
+
<sup><a name="note372" href="#note372"><b>372)</b></a></sup> See the description of the RSIZE_MAX macro in <a href="#7.20"><stdint.h></a>.
+ <sup><a name="note373" href="#note373"><b>373)</b></a></sup> The macro RSIZE_MAX need not expand to a constant expression.
-[<a name="
#p581" href="p581">page 581</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p581" href="#p581">page 581</a>] (<a href="#Contents">Contents</a>)
is no object size that is considered a runtime-constraint violation.
<a name="K.3.5" href="#K.3.5"><b> K.3.5 Input/output <stdio.h></b></a>
which is the type size_t.
<a name="K.3.5.1" href="#K.3.5.1"><b> K.3.5.1 Operations on files</b></a>
<a name="K.3.5.1.1" href="#K.3.5.1.1"><b> K.3.5.1.1 The tmpfile_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
errno_t tmpfile_s(FILE * restrict * restrict streamptr);
Runtime-constraints
2 streamptr shall not be a null pointer.
3 If there is a runtime-constraint violation, tmpfile_s does not attempt to create a file.
- Description
+<b> Description</b>
4 The tmpfile_s function creates a temporary binary file that is different from any other
existing file and that will automatically be removed when it is closed or at program
termination. If the program terminates abnormally, whether an open temporary file is
with the meaning that mode has in the fopen_s function (including the mode's effect
on exclusive access and file permissions).
-
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5 If the file was created successfully, then the pointer to FILE pointed to by streamptr
will be set to the pointer to the object controlling the opened file. Otherwise, the pointer
the program (this limit may be shared with tmpnam_s) and there should be no limit on
the number simultaneously open other than this limit and any limit on the number of open
files (FOPEN_MAX).
- Returns
+<b> Returns</b>
6 The tmpfile_s function returns zero if it created the file. If it did not create the file or
there was a runtime-constraint violation, tmpfile_s returns a nonzero value.
<a name="K.3.5.1.2" href="#K.3.5.1.2"><b> K.3.5.1.2 The tmpnam_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
errno_t tmpnam_s(char *s, rsize_t maxsize);
Runtime-constraints
2 s shall not be a null pointer. maxsize shall be less than or equal to RSIZE_MAX.
maxsize shall be greater than the length of the generated file name string.
- Description
+<b> Description</b>
3 The tmpnam_s function generates a string that is a valid file name and that is not the
- same as the name of an existing file.374) The function is potentially capable of generating
+ same as the name of an existing file.<sup><a href="#note374"><b>374)</b></a></sup> The function is potentially capable of generating
TMP_MAX_S different strings, but any or all of them may already be in use by existing
files and thus not be suitable return values. The lengths of these strings shall be less than
the value of the L_tmpnam_s macro.
- 374) Files created using strings generated by the tmpnam_s function are temporary only in the sense that
+ <sup><a name="note374" href="#note374"><b>374)</b></a></sup> Files created using strings generated by the tmpnam_s function are temporary only in the sense that
their names should not collide with those generated by conventional naming rules for the
implementation. It is still necessary to use the remove function to remove such files when their use
is ended, and before program termination. Implementations should take care in choosing the patterns
race condition and possible conflict when multiple programs run simultaneously by the same user
generate the same temporary file names.
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+[<a name="
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6 The implementation shall behave as if no library function except tmpnam calls the
- tmpnam_s function.375)
+ tmpnam_s function.<sup><a href="#note375"><b>375)</b></a></sup>
Recommended practice
7 After a program obtains a file name using the tmpnam_s function and before the
program creates a file with that name, the possibility exists that someone else may create
should be used instead of tmpnam_s when possible. One situation that requires the use
of the tmpnam_s function is when the program needs to create a temporary directory
rather than a temporary file.
- Returns
+<b> Returns</b>
8 If no suitable string can be generated, or if there is a runtime-constraint violation, the
tmpnam_s function writes a null character to s[0] (only if s is not null and maxsize
is greater than zero) and returns a nonzero value.
10 The value of the macro TMP_MAX_S shall be at least 25.
<a name="K.3.5.2" href="#K.3.5.2"><b> K.3.5.2 File access functions</b></a>
<a name="K.3.5.2.1" href="#K.3.5.2.1"><b> K.3.5.2.1 The fopen_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
errno_t fopen_s(FILE * restrict * restrict streamptr,
- 375) An implementation may have tmpnam call tmpnam_s (perhaps so there is only one naming
+ <sup><a name="note375" href="#note375"><b>375)</b></a></sup> An implementation may have tmpnam call tmpnam_s (perhaps so there is only one naming
convention for temporary files), but this is not required.
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#p584" href="p584">page 584</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p584" href="#p584">page 584</a>] (<a href="#Contents">Contents</a>)
- Description
+<b> Description</b>
4 The fopen_s function opens the file whose name is the string pointed to by
filename, and associates a stream with it.
5 The mode string shall be as described for fopen, with the addition that modes starting
underlying system supports it, the file shall have a file permission that prevents other
users on the system from accessing the file. If the file is being created and first character
of the mode string is 'u', then by the time the file has been closed, it shall have the
- system default file access permissions.376)
+ system default file access permissions.<sup><a href="#note376"><b>376)</b></a></sup>
8 If the file was opened successfully, then the pointer to FILE pointed to by streamptr
will be set to the pointer to the object controlling the opened file. Otherwise, the pointer
- 376) These are the same permissions that the file would have been created with by fopen.
+ <sup><a name="note376" href="#note376"><b>376)</b></a></sup> These are the same permissions that the file would have been created with by fopen.
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#p585" href="p585">page 585</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p585" href="#p585">page 585</a>] (<a href="#Contents">Contents</a>)
to FILE pointed to by streamptr will be set to a null pointer.
- Returns
+<b> Returns</b>
9 The fopen_s function returns zero if it opened the file. If it did not open the file or if
there was a runtime-constraint violation, fopen_s returns a nonzero value.
<a name="K.3.5.2.2" href="#K.3.5.2.2"><b> K.3.5.2.2 The freopen_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
errno_t freopen_s(FILE * restrict * restrict newstreamptr,
3 If there is a runtime-constraint violation, freopen_s neither attempts to close any file
associated with stream nor attempts to open a file. Furthermore, if newstreamptr is
not a null pointer, fopen_s sets *newstreamptr to the null pointer.
- Description
+<b> Description</b>
4 The freopen_s function opens the file whose name is the string pointed to by
filename and associates the stream pointed to by stream with it. The mode
argument has the same meaning as in the fopen_s function (including the mode's effect
7 If the file was opened successfully, then the pointer to FILE pointed to by
newstreamptr will be set to the value of stream. Otherwise, the pointer to FILE
pointed to by newstreamptr will be set to a null pointer.
- Returns
+<b> Returns</b>
8 The freopen_s function returns zero if it opened the file. If it did not open the file or
there was a runtime-constraint violation, freopen_s returns a nonzero value.
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+[<a name="
p586" href="#p586">page 586</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.5.3" href="#K.3.5.3"><b> K.3.5.3 Formatted input/output functions</b></a>
1 Unless explicitly stated otherwise, if the execution of a function described in this
subclause causes copying to take place between objects that overlap, the objects take on
unspecified values.
<a name="K.3.5.3.1" href="#K.3.5.3.1"><b> K.3.5.3.1 The fprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
int fprintf_s(FILE * restrict stream,
const char * restrict format, ...);
Runtime-constraints
-2 Neither stream nor format shall be a null pointer. The %n specifier377) (modified or
+2 Neither stream nor format shall be a null pointer. The %n specifier<sup><a href="#note377"><b>377)</b></a></sup> (modified or
not by flags, field width, or precision) shall not appear in the string pointed to by
format. Any argument to fprintf_s corresponding to a %s specifier shall not be a
null pointer.
-3 If there is a runtime-constraint violation,378) the fprintf_s function does not attempt
+3 If there is a runtime-constraint violation,<sup><a href="#note378"><b>378)</b></a></sup> the fprintf_s function does not attempt
to produce further output, and it is unspecified to what extent fprintf_s produced
output before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The fprintf_s function is equivalent to the fprintf function except for the explicit
runtime-constraints listed above.
- Returns
+<b> Returns</b>
5 The fprintf_s function returns the number of characters transmitted, or a negative
value if an output error, encoding error, or runtime-constraint violation occurred.
- 377) It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
+ <sup><a name="note377" href="#note377"><b>377)</b></a></sup> It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
at by format when those characters are not a interpreted as a %n specifier. For example, if the entire
format string was %%n.
- 378) Because an implementation may treat any undefined behavior as a runtime-constraint violation, an
+ <sup><a name="note378" href="#note378"><b>378)</b></a></sup> Because an implementation may treat any undefined behavior as a runtime-constraint violation, an
implementation may treat any unsupported specifiers in the string pointed to by format as a runtime-
constraint violation.
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+[<a name="
p587" href="#p587">page 587</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.5.3.2" href="#K.3.5.3.2"><b> K.3.5.3.2 The fscanf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
int fscanf_s(FILE * restrict stream,
Runtime-constraints
2 Neither stream nor format shall be a null pointer. Any argument indirected though in
order to store converted input shall not be a null pointer.
-3 If there is a runtime-constraint violation,379) the fscanf_s function does not attempt to
+3 If there is a runtime-constraint violation,<sup><a href="#note379"><b>379)</b></a></sup> the fscanf_s function does not attempt to
perform further input, and it is unspecified to what extent fscanf_s performed input
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The fscanf_s function is equivalent to fscanf except that the c, s, and [ conversion
specifiers apply to a pair of arguments (unless assignment suppression is indicated by a
*). The first of these arguments is the same as for fscanf. That argument is
immediately followed in the argument list by the second argument, which has type
rsize_t and gives the number of elements in the array pointed to by the first argument
of the pair. If the first argument points to a scalar object, it is considered to be an array of
- one element.380)
+ one element.<sup><a href="#note380"><b>380)</b></a></sup>
5 A matching failure occurs if the number of elements in a receiving object is insufficient to
hold the converted input (including any trailing null character).
- Returns
+<b> Returns</b>
6 The fscanf_s function returns the value of the macro EOF if an input failure occurs
before any conversion or if there is a runtime-constraint violation. Otherwise, the
- 379) Because an implementation may treat any undefined behavior as a runtime-constraint violation, an
+ <sup><a name="note379" href="#note379"><b>379)</b></a></sup> Because an implementation may treat any undefined behavior as a runtime-constraint violation, an
implementation may treat any unsupported specifiers in the string pointed to by format as a runtime-
constraint violation.
- 380) If the format is known at translation time, an implementation may issue a diagnostic for any argument
+ <sup><a name="note380" href="#note380"><b>380)</b></a></sup> If the format is known at translation time, an implementation may issue a diagnostic for any argument
used to store the result from a c, s, or [ conversion specifier if that argument is not followed by an
argument of a type compatible with rsize_t. A limited amount of checking may be done if even if
the format is not known at translation time. For example, an implementation may issue a diagnostic
diagnostic could flag any non-pointer argument following format that did not have a type
compatible with rsize_t.
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+[<a name="
p588" href="#p588">page 588</a>] (<a href="#Contents">Contents</a>)
fscanf_s function returns the number of input items assigned, which can be fewer than
provided for, or even zero, in the event of an early matching failure.
array of six characters to store it.
<a name="K.3.5.3.3" href="#K.3.5.3.3"><b> K.3.5.3.3 The printf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
int printf_s(const char * restrict format, ...);
Runtime-constraints
-2 format shall not be a null pointer. The %n specifier381) (modified or not by flags, field
+2 format shall not be a null pointer. The %n specifier<sup><a href="#note381"><b>381)</b></a></sup> (modified or not by flags, field
width, or precision) shall not appear in the string pointed to by format. Any argument
to printf_s corresponding to a %s specifier shall not be a null pointer.
3 If there is a runtime-constraint violation, the printf_s function does not attempt to
before discovering the runtime-constraint violation.
- 381) It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
+ <sup><a name="note381" href="#note381"><b>381)</b></a></sup> It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
at by format when those characters are not a interpreted as a %n specifier. For example, if the entire
format string was %%n.
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#p589" href="p589">page 589</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p589" href="#p589">page 589</a>] (<a href="#Contents">Contents</a>)
- Description
+<b> Description</b>
4 The printf_s function is equivalent to the printf function except for the explicit
runtime-constraints listed above.
- Returns
+<b> Returns</b>
5 The printf_s function returns the number of characters transmitted, or a negative
value if an output error, encoding error, or runtime-constraint violation occurred.
<a name="K.3.5.3.4" href="#K.3.5.3.4"><b> K.3.5.3.4 The scanf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
int scanf_s(const char * restrict format, ...);
3 If there is a runtime-constraint violation, the scanf_s function does not attempt to
perform further input, and it is unspecified to what extent scanf_s performed input
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The scanf_s function is equivalent to fscanf_s with the argument stdin
interposed before the arguments to scanf_s.
- Returns
+<b> Returns</b>
5 The scanf_s function returns the value of the macro EOF if an input failure occurs
before any conversion or if there is a runtime-constraint violation. Otherwise, the
scanf_s function returns the number of input items assigned, which can be fewer than
provided for, or even zero, in the event of an early matching failure.
<a name="K.3.5.3.5" href="#K.3.5.3.5"><b> K.3.5.3.5 The snprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
int snprintf_s(char * restrict s, rsize_t n,
const char * restrict format, ...);
Runtime-constraints
2 Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
- than RSIZE_MAX. The %n specifier382) (modified or not by flags, field width, or
+ than RSIZE_MAX. The %n specifier<sup><a href="#note382"><b>382)</b></a></sup> (modified or not by flags, field width, or
precision) shall not appear in the string pointed to by format. Any argument to
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+
+[<a name="p590" href="#p590">page 590</a>] (<a href="#Contents">Contents</a>)
snprintf_s corresponding to a %s specifier shall not be a null pointer. No encoding
error shall occur.
3 If there is a runtime-constraint violation, then if s is not a null pointer and n is greater
than zero and less than RSIZE_MAX, then the snprintf_s function sets s[0] to the
null character.
- Description
+<b> Description</b>
4 The snprintf_s function is equivalent to the snprintf function except for the
explicit runtime-constraints listed above.
5 The snprintf_s function, unlike sprintf_s, will truncate the result to fit within the
array pointed to by s.
- Returns
+<b> Returns</b>
6 The snprintf_s function returns the number of characters that would have been
written had n been sufficiently large, not counting the terminating null character, or a
negative value if a runtime-constraint violation occurred. Thus, the null-terminated
output has been completely written if and only if the returned value is nonnegative and
less than n.
<a name="K.3.5.3.6" href="#K.3.5.3.6"><b> K.3.5.3.6 The sprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
int sprintf_s(char * restrict s, rsize_t n,
2 Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
than RSIZE_MAX. The number of characters (including the trailing null) required for the
result to be written to the array pointed to by s shall not be greater than n. The %n
- specifier383) (modified or not by flags, field width, or precision) shall not appear in the
+ specifier<sup><a href="#note383"><b>383)</b></a></sup> (modified or not by flags, field width, or precision) shall not appear in the
string pointed to by format. Any argument to sprintf_s corresponding to a %s
specifier shall not be a null pointer. No encoding error shall occur.
- 382) It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
+ <sup><a name="note382" href="#note382"><b>382)</b></a></sup> It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
at by format when those characters are not a interpreted as a %n specifier. For example, if the entire
format string was %%n.
- 383) It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
+ <sup><a name="note383" href="#note383"><b>383)</b></a></sup> It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
at by format when those characters are not a interpreted as a %n specifier. For example, if the entire
format string was %%n.
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#p591" href="p591">page 591</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p591" href="#p591">page 591</a>] (<a href="#Contents">Contents</a>)
3 If there is a runtime-constraint violation, then if s is not a null pointer and n is greater
than zero and less than RSIZE_MAX, then the sprintf_s function sets s[0] to the
null character.
- Description
+<b> Description</b>
4 The sprintf_s function is equivalent to the sprintf function except for the
parameter n and the explicit runtime-constraints listed above.
5 The sprintf_s function, unlike snprintf_s, treats a result too big for the array
pointed to by s as a runtime-constraint violation.
- Returns
+<b> Returns</b>
6 If no runtime-constraint violation occurred, the sprintf_s function returns the number
of characters written in the array, not counting the terminating null character. If an
encoding error occurred, sprintf_s returns a negative value. If any other runtime-
constraint violation occurred, sprintf_s returns zero.
<a name="K.3.5.3.7" href="#K.3.5.3.7"><b> K.3.5.3.7 The sscanf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
int sscanf_s(const char * restrict s,
3 If there is a runtime-constraint violation, the sscanf_s function does not attempt to
perform further input, and it is unspecified to what extent sscanf_s performed input
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The sscanf_s function is equivalent to fscanf_s, except that input is obtained from
a string (specified by the argument s) rather than from a stream. Reaching the end of the
string is equivalent to encountering end-of-file for the fscanf_s function. If copying
takes place between objects that overlap, the objects take on unspecified values.
- Returns
+<b> Returns</b>
5 The sscanf_s function returns the value of the macro EOF if an input failure occurs
before any conversion or if there is a runtime-constraint violation. Otherwise, the
sscanf_s function returns the number of input items assigned, which can be fewer than
provided for, or even zero, in the event of an early matching failure.
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#p592" href="p592">page 592</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p592" href="#p592">page 592</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.5.3.8" href="#K.3.5.3.8"><b> K.3.5.3.8 The vfprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
const char * restrict format,
va_list arg);
Runtime-constraints
-2 Neither stream nor format shall be a null pointer. The %n specifier384) (modified or
+2 Neither stream nor format shall be a null pointer. The %n specifier<sup><a href="#note384"><b>384)</b></a></sup> (modified or
not by flags, field width, or precision) shall not appear in the string pointed to by
format. Any argument to vfprintf_s corresponding to a %s specifier shall not be a
null pointer.
3 If there is a runtime-constraint violation, the vfprintf_s function does not attempt to
produce further output, and it is unspecified to what extent vfprintf_s produced
output before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The vfprintf_s function is equivalent to the vfprintf function except for the
explicit runtime-constraints listed above.
- Returns
+<b> Returns</b>
5 The vfprintf_s function returns the number of characters transmitted, or a negative
value if an output error, encoding error, or runtime-constraint violation occurred.
<a name="K.3.5.3.9" href="#K.3.5.3.9"><b> K.3.5.3.9 The vfscanf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
- 384) It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
+ <sup><a name="note384" href="#note384"><b>384)</b></a></sup> It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
at by format when those characters are not a interpreted as a %n specifier. For example, if the entire
format string was %%n.
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#p593" href="p593">page 593</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p593" href="#p593">page 593</a>] (<a href="#Contents">Contents</a>)
Runtime-constraints
2 Neither stream nor format shall be a null pointer. Any argument indirected though in
3 If there is a runtime-constraint violation, the vfscanf_s function does not attempt to
perform further input, and it is unspecified to what extent vfscanf_s performed input
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The vfscanf_s function is equivalent to fscanf_s, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vfscanf_s function does not invoke the
- va_end macro.385)
- Returns
+ va_end macro.<sup><a href="#note385"><b>385)</b></a></sup>
+<b> Returns</b>
5 The vfscanf_s function returns the value of the macro EOF if an input failure occurs
before any conversion or if there is a runtime-constraint violation. Otherwise, the
vfscanf_s function returns the number of input items assigned, which can be fewer
than provided for, or even zero, in the event of an early matching failure.
<a name="K.3.5.3.10" href="#K.3.5.3.10"><b> K.3.5.3.10 The vprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
int vprintf_s(const char * restrict format,
va_list arg);
Runtime-constraints
-2 format shall not be a null pointer. The %n specifier386) (modified or not by flags, field
+2 format shall not be a null pointer. The %n specifier<sup><a href="#note386"><b>386)</b></a></sup> (modified or not by flags, field
width, or precision) shall not appear in the string pointed to by format. Any argument
to vprintf_s corresponding to a %s specifier shall not be a null pointer.
3 If there is a runtime-constraint violation, the vprintf_s function does not attempt to
produce further output, and it is unspecified to what extent vprintf_s produced output
before discovering the runtime-constraint violation.
- 385) As the functions vfprintf_s, vfscanf_s, vprintf_s, vscanf_s, vsnprintf_s,
+ <sup><a name="note385" href="#note385"><b>385)</b></a></sup> As the functions vfprintf_s, vfscanf_s, vprintf_s, vscanf_s, vsnprintf_s,
vsprintf_s, and vsscanf_s invoke the va_arg macro, the value of arg after the return is
indeterminate.
- 386) It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
+ <sup><a name="note386" href="#note386"><b>386)</b></a></sup> It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
at by format when those characters are not a interpreted as a %n specifier. For example, if the entire
format string was %%n.
-[<a name="
#p594" href="p594">page 594</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p594" href="#p594">page 594</a>] (<a href="#Contents">Contents</a>)
- Description
+<b> Description</b>
4 The vprintf_s function is equivalent to the vprintf function except for the explicit
runtime-constraints listed above.
- Returns
+<b> Returns</b>
5 The vprintf_s function returns the number of characters transmitted, or a negative
value if an output error, encoding error, or runtime-constraint violation occurred.
<a name="K.3.5.3.11" href="#K.3.5.3.11"><b> K.3.5.3.11 The vscanf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
3 If there is a runtime-constraint violation, the vscanf_s function does not attempt to
perform further input, and it is unspecified to what extent vscanf_s performed input
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The vscanf_s function is equivalent to scanf_s, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vscanf_s function does not invoke the
- va_end macro.387)
- Returns
+ va_end macro.<sup><a href="#note387"><b>387)</b></a></sup>
+<b> Returns</b>
5 The vscanf_s function returns the value of the macro EOF if an input failure occurs
before any conversion or if there is a runtime-constraint violation. Otherwise, the
vscanf_s function returns the number of input items assigned, which can be fewer than
- 387) As the functions vfprintf_s, vfscanf_s, vprintf_s, vscanf_s, vsnprintf_s,
+ <sup><a name="note387" href="#note387"><b>387)</b></a></sup> As the functions vfprintf_s, vfscanf_s, vprintf_s, vscanf_s, vsnprintf_s,
vsprintf_s, and vsscanf_s invoke the va_arg macro, the value of arg after the return is
indeterminate.
-[<a name="
#p595" href="p595">page 595</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p595" href="#p595">page 595</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.5.3.12" href="#K.3.5.3.12"><b> K.3.5.3.12 The vsnprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
va_list arg);
Runtime-constraints
2 Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
- than RSIZE_MAX. The %n specifier388) (modified or not by flags, field width, or
+ than RSIZE_MAX. The %n specifier<sup><a href="#note388"><b>388)</b></a></sup> (modified or not by flags, field width, or
precision) shall not appear in the string pointed to by format. Any argument to
vsnprintf_s corresponding to a %s specifier shall not be a null pointer. No encoding
error shall occur.
3 If there is a runtime-constraint violation, then if s is not a null pointer and n is greater
than zero and less than RSIZE_MAX, then the vsnprintf_s function sets s[0] to the
null character.
- Description
+<b> Description</b>
4 The vsnprintf_s function is equivalent to the vsnprintf function except for the
explicit runtime-constraints listed above.
5 The vsnprintf_s function, unlike vsprintf_s, will truncate the result to fit within
the array pointed to by s.
- Returns
+<b> Returns</b>
6 The vsnprintf_s function returns the number of characters that would have been
written had n been sufficiently large, not counting the terminating null character, or a
negative value if a runtime-constraint violation occurred. Thus, the null-terminated
- 388) It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
+ <sup><a name="note388" href="#note388"><b>388)</b></a></sup> It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
at by format when those characters are not a interpreted as a %n specifier. For example, if the entire
format string was %%n.
-[<a name="
#p596" href="p596">page 596</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p596" href="#p596">page 596</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.5.3.13" href="#K.3.5.3.13"><b> K.3.5.3.13 The vsprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
2 Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
than RSIZE_MAX. The number of characters (including the trailing null) required for the
result to be written to the array pointed to by s shall not be greater than n. The %n
- specifier389) (modified or not by flags, field width, or precision) shall not appear in the
+ specifier<sup><a href="#note389"><b>389)</b></a></sup> (modified or not by flags, field width, or precision) shall not appear in the
string pointed to by format. Any argument to vsprintf_s corresponding to a %s
specifier shall not be a null pointer. No encoding error shall occur.
3 If there is a runtime-constraint violation, then if s is not a null pointer and n is greater
than zero and less than RSIZE_MAX, then the vsprintf_s function sets s[0] to the
null character.
- Description
+<b> Description</b>
4 The vsprintf_s function is equivalent to the vsprintf function except for the
parameter n and the explicit runtime-constraints listed above.
5 The vsprintf_s function, unlike vsnprintf_s, treats a result too big for the array
pointed to by s as a runtime-constraint violation.
- Returns
+<b> Returns</b>
6 If no runtime-constraint violation occurred, the vsprintf_s function returns the
number of characters written in the array, not counting the terminating null character. If
an encoding error occurred, vsprintf_s returns a negative value. If any other
- 389) It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
+ <sup><a name="note389" href="#note389"><b>389)</b></a></sup> It is not a runtime-constraint violation for the characters %n to appear in sequence in the string pointed
at by format when those characters are not a interpreted as a %n specifier. For example, if the entire
format string was %%n.
-[<a name="
#p597" href="p597">page 597</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p597" href="#p597">page 597</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.5.3.14" href="#K.3.5.3.14"><b> K.3.5.3.14 The vsscanf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
3 If there is a runtime-constraint violation, the vsscanf_s function does not attempt to
perform further input, and it is unspecified to what extent vsscanf_s performed input
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The vsscanf_s function is equivalent to sscanf_s, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vsscanf_s function does not invoke the
- va_end macro.390)
- Returns
+ va_end macro.<sup><a href="#note390"><b>390)</b></a></sup>
+<b> Returns</b>
5 The vsscanf_s function returns the value of the macro EOF if an input failure occurs
before any conversion or if there is a runtime-constraint violation. Otherwise, the
vscanf_s function returns the number of input items assigned, which can be fewer than
provided for, or even zero, in the event of an early matching failure.
<a name="K.3.5.4" href="#K.3.5.4"><b> K.3.5.4 Character input/output functions</b></a>
<a name="K.3.5.4.1" href="#K.3.5.4.1"><b> K.3.5.4.1 The gets_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
char *gets_s(char *s, rsize_t n);
- 390) As the functions vfprintf_s, vfscanf_s, vprintf_s, vscanf_s, vsnprintf_s,
+ <sup><a name="note390" href="#note390"><b>390)</b></a></sup> As the functions vfprintf_s, vfscanf_s, vprintf_s, vscanf_s, vsnprintf_s,
vsprintf_s, and vsscanf_s invoke the va_arg macro, the value of arg after the return is
indeterminate.
-[<a name="
#p598" href="p598">page 598</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p598" href="#p598">page 598</a>] (<a href="#Contents">Contents</a>)
Runtime-constraints
2 s shall not be a null pointer. n shall neither be equal to zero nor be greater than
RSIZE_MAX. A new-line character, end-of-file, or read error shall occur within reading
- n-1 characters from stdin.391)
+ n-1 characters from stdin.<sup><a href="#note391"><b>391)</b></a></sup>
3 If there is a runtime-constraint violation, s[0] is set to the null character, and characters
are read and discarded from stdin until a new-line character is read, or end-of-file or a
read error occurs.
- Description
+<b> Description</b>
4 The gets_s function reads at most one less than the number of characters specified by n
from the stream pointed to by stdin, into the array pointed to by s. No additional
characters are read after a new-line character (which is discarded) or after end-of-file.
attention to the presence or absence of a new-line character in the result array. Consider
using fgets (along with any needed processing based on new-line characters) instead of
gets_s.
- Returns
+<b> Returns</b>
7 The gets_s function returns s if successful. If there was a runtime-constraint violation,
or if end-of-file is encountered and no characters have been read into the array, or if a
read error occurs during the operation, then a null pointer is returned.
- 391) The gets_s function, unlike the historical gets function, makes it a runtime-constraint violation for
+ <sup><a name="note391" href="#note391"><b>391)</b></a></sup> The gets_s function, unlike the historical gets function, makes it a runtime-constraint violation for
a line of input to overflow the buffer to store it. Unlike the fgets function, gets_s maintains a
one-to-one relationship between input lines and successful calls to gets_s. Programs that use gets
expect such a relationship.
-[<a name="
#p599" href="p599">page 599</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p599" href="#p599">page 599</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.6" href="#K.3.6"><b> K.3.6 General utilities <stdlib.h></b></a>
1 The header <a href="#7.22"><stdlib.h></a> defines three types.
errno_t error);
<a name="K.3.6.1" href="#K.3.6.1"><b> K.3.6.1 Runtime-constraint handling</b></a>
<a name="K.3.6.1.1" href="#K.3.6.1.1"><b> K.3.6.1.1 The set_constraint_handler_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.22"><stdlib.h></a>
constraint_handler_t set_constraint_handler_s(
constraint_handler_t handler);
- Description
+<b> Description</b>
2 The set_constraint_handler_s function sets the runtime-constraint handler to
be handler. The runtime-constraint handler is the function to be called when a library
function detects a runtime-constraint violation. Only the most recent handler registered
return value of the function is passed. Otherwise, a positive value of type
errno_t is passed.
-
-
-[<a name="#p600" href="p600">page 600</a>] (<a href="#Contents">Contents</a>)
+[<a name="p600" href="#p600">page 600</a>] (<a href="#Contents">Contents</a>)
4 The implementation has a default constraint handler that is used if no calls to the
set_constraint_handler_s function have been made. The behavior of the
default handler is implementation-defined, and it may cause the program to exit or abort.
5 If the handler argument to set_constraint_handler_s is a null pointer, the
implementation default handler becomes the current constraint handler.
- Returns
+<b> Returns</b>
6 The set_constraint_handler_s function returns a pointer to the previously
- registered handler.392)
+ registered handler.<sup><a href="#note392"><b>392)</b></a></sup>
<a name="K.3.6.1.2" href="#K.3.6.1.2"><b> K.3.6.1.2 The abort_handler_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.22"><stdlib.h></a>
void abort_handler_s(
const char * restrict msg,
void * restrict ptr,
errno_t error);
- Description
+<b> Description</b>
2 A pointer to the abort_handler_s function shall be a suitable argument to the
set_constraint_handler_s function.
3 The abort_handler_s function writes a message on the standard error stream in an
implementation-defined format. The message shall include the string pointed to by msg.
- The abort_handler_s function then calls the abort function.393)
- Returns
+ The abort_handler_s function then calls the abort function.<sup><a href="#note393"><b>393)</b></a></sup>
+<b> Returns</b>
4 The abort_handler_s function does not return to its caller.
- 392) If the previous handler was registered by calling set_constraint_handler_s with a null
+ <sup><a name="note392" href="#note392"><b>392)</b></a></sup> If the previous handler was registered by calling set_constraint_handler_s with a null
pointer argument, a pointer to the implementation default handler is returned (not NULL).
- 393) Many implementations invoke a debugger when the abort function is called.
+ <sup><a name="note393" href="#note393"><b>393)</b></a></sup> Many implementations invoke a debugger when the abort function is called.
-[<a name="
#p601" href="p601">page 601</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p601" href="#p601">page 601</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.6.1.3" href="#K.3.6.1.3"><b> K.3.6.1.3 The ignore_handler_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.22"><stdlib.h></a>
void ignore_handler_s(
const char * restrict msg,
void * restrict ptr,
errno_t error);
- Description
+<b> Description</b>
2 A pointer to the ignore_handler_s function shall be a suitable argument to the
set_constraint_handler_s function.
-3 The ignore_handler_s function simply returns to its caller.394)
- Returns
+3 The ignore_handler_s function simply returns to its caller.<sup><a href="#note394"><b>394)</b></a></sup>
+<b> Returns</b>
4 The ignore_handler_s function returns no value.
<a name="K.3.6.2" href="#K.3.6.2"><b> K.3.6.2 Communication with the environment</b></a>
<a name="K.3.6.2.1" href="#K.3.6.2.1"><b> K.3.6.2.1 The getenv_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.22"><stdlib.h></a>
errno_t getenv_s(size_t * restrict len,
RSIZE_MAX. If maxsize is not equal to zero, then value shall not be a null pointer.
3 If there is a runtime-constraint violation, the integer pointed to by len is set to 0 (if len
is not null), and the environment list is not searched.
- Description
+<b> Description</b>
4 The getenv_s function searches an environment list, provided by the host environment,
for a string that matches the string pointed to by name.
- 394) If the runtime-constraint handler is set to the ignore_handler_s function, any library function in
+ <sup><a name="note394" href="#note394"><b>394)</b></a></sup> If the runtime-constraint handler is set to the ignore_handler_s function, any library function in
which a runtime-constraint violation occurs will return to its caller. The caller can determine whether
a runtime-constraint violation occurred based on the library function's specification (usually, the
library function returns a nonzero errno_t).
-[<a name="
#p602" href="p602">page 602</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p602" href="#p602">page 602</a>] (<a href="#Contents">Contents</a>)
5 If that name is found then getenv_s performs the following actions. If len is not a
null pointer, the length of the string associated with the matched list member is stored in
zero, then value[0] is set to the null character.
7 The set of environment names and the method for altering the environment list are
implementation-defined.
- Returns
+<b> Returns</b>
8 The getenv_s function returns zero if the specified name is found and the associated
string was successfully stored in value. Otherwise, a nonzero value is returned.
<a name="K.3.6.3" href="#K.3.6.3"><b> K.3.6.3 Searching and sorting utilities</b></a>
rearrangement, and the pointer to the array may be null.
2 The implementation shall ensure that the second argument of the comparison function
(when called from bsearch_s), or both arguments (when called from qsort_s), are
- pointers to elements of the array.395) The first argument when called from bsearch_s
+ pointers to elements of the array.<sup><a href="#note395"><b>395)</b></a></sup> The first argument when called from bsearch_s
shall equal key.
3 The comparison function shall not alter the contents of either the array or search key. The
implementation may reorder elements of the array between calls to the comparison
- 395) That is, if the value passed is p, then the following expressions are always valid and nonzero:
+ <sup><a name="note395" href="#note395"><b>395)</b></a></sup> That is, if the value passed is p, then the following expressions are always valid and nonzero:
((char *)p - (char *)base) % size == 0
(char *)p >= (char *)base
(char *)p < (char *)base + nmemb * size
-
-[<a name="#p603" href="p603">page 603</a>] (<a href="#Contents">Contents</a>)
+[<a name="p603" href="#p603">page 603</a>] (<a href="#Contents">Contents</a>)
5 A sequence point occurs immediately before and immediately after each call to the
comparison function, and also between any call to the comparison function and any
movement of the objects passed as arguments to that call.
<a name="K.3.6.3.1" href="#K.3.6.3.1"><b> K.3.6.3.1 The bsearch_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.22"><stdlib.h></a>
void *bsearch_s(const void *key, const void *base,
zero, then none of key, base, or compar shall be a null pointer.
3 If there is a runtime-constraint violation, the bsearch_s function does not search the
array.
- Description
+<b> Description</b>
4 The bsearch_s function searches an array of nmemb objects, the initial element of
which is pointed to by base, for an element that matches the object pointed to by key.
The size of each element of the array is specified by size.
return an integer less than, equal to, or greater than zero if the key object is considered,
respectively, to be less than, to match, or to be greater than the array element. The array
shall consist of: all the elements that compare less than, all the elements that compare
- equal to, and all the elements that compare greater than the key object, in that order.396)
+ equal to, and all the elements that compare greater than the key object, in that order.<sup><a href="#note396"><b>396)</b></a></sup>
The third argument to the comparison function is the context argument passed to
bsearch_s. The sole use of context by bsearch_s is to pass it to the comparison
- function.397)
+ function.<sup><a href="#note397"><b>397)</b></a></sup>
- 396) In practice, this means that the entire array has been sorted according to the comparison function.
- 397) The context argument is for the use of the comparison function in performing its duties. For
+ <sup><a name="note396" href="#note396"><b>396)</b></a></sup> In practice, this means that the entire array has been sorted according to the comparison function.
+ <sup><a name="note397" href="#note397"><b>397)</b></a></sup> The context argument is for the use of the comparison function in performing its duties. For
example, it might specify a collating sequence used by the comparison function.
-[<a name="
#p604" href="p604">page 604</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p604" href="#p604">page 604</a>] (<a href="#Contents">Contents</a>)
- Returns
+<b> Returns</b>
6 The bsearch_s function returns a pointer to a matching element of the array, or a null
pointer if no match is found or there is a runtime-constraint violation. If two elements
compare as equal, which element is matched is unspecified.
<a name="K.3.6.3.2" href="#K.3.6.3.2"><b> K.3.6.3.2 The qsort_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.22"><stdlib.h></a>
errno_t qsort_s(void *base, rsize_t nmemb, rsize_t size,
2 Neither nmemb nor size shall be greater than RSIZE_MAX. If nmemb is not equal to
zero, then neither base nor compar shall be a null pointer.
3 If there is a runtime-constraint violation, the qsort_s function does not sort the array.
- Description
+<b> Description</b>
4 The qsort_s function sorts an array of nmemb objects, the initial element of which is
pointed to by base. The size of each object is specified by size.
5 The contents of the array are sorted into ascending order according to a comparison
to, or greater than zero if the first argument is considered to be respectively less than,
equal to, or greater than the second. The third argument to the comparison function is the
context argument passed to qsort_s. The sole use of context by qsort_s is to
- pass it to the comparison function.398)
+ pass it to the comparison function.<sup><a href="#note398"><b>398)</b></a></sup>
6 If two elements compare as equal, their relative order in the resulting sorted array is
unspecified.
- Returns
+<b> Returns</b>
7 The qsort_s function returns zero if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
- 398) The context argument is for the use of the comparison function in performing its duties. For
+ <sup><a name="note398" href="#note398"><b>398)</b></a></sup> The context argument is for the use of the comparison function in performing its duties. For
example, it might specify a collating sequence used by the comparison function.
-[<a name="
#p605" href="p605">page 605</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p605" href="#p605">page 605</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.6.4" href="#K.3.6.4"><b> K.3.6.4 Multibyte/wide character conversion functions</b></a>
1 The behavior of the multibyte character functions is affected by the LC_CTYPE category
pointer. Subsequent calls with s as other than a null pointer cause the internal conversion
state of the function to be altered as necessary. A call with s as a null pointer causes
these functions to set the int pointed to by their status argument to a nonzero value if
- encodings have state dependency, and zero otherwise.399) Changing the LC_CTYPE
+ encodings have state dependency, and zero otherwise.<sup><a href="#note399"><b>399)</b></a></sup> Changing the LC_CTYPE
category causes the conversion state of these functions to be indeterminate.
<a name="K.3.6.4.1" href="#K.3.6.4.1"><b> K.3.6.4.1 The wctomb_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.22"><stdlib.h></a>
errno_t wctomb_s(int * restrict status,
4 If there is a runtime-constraint violation, wctomb_s does not modify the int pointed to
by status, and if s is not a null pointer, no more than smax elements in the array
pointed to by s will be accessed.
- Description
+<b> Description</b>
5 The wctomb_s function determines n and stores the multibyte character representation
of wc in the array whose first element is pointed to by s (if s is not a null pointer). The
number of characters stored never exceeds MB_CUR_MAX or smax. If wc is a null wide
- 399) If the locale employs special bytes to change the shift state, these bytes do not produce separate wide
+ <sup><a name="note399" href="#note399"><b>399)</b></a></sup> If the locale employs special bytes to change the shift state, these bytes do not produce separate wide
character codes, but are grouped with an adjacent multibyte character.
-[<a name="
#p606" href="p606">page 606</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p606" href="#p606">page 606</a>] (<a href="#Contents">Contents</a>)
7 If s is a null pointer, the wctomb_s function stores into the int pointed to by status a
nonzero or zero value, if multibyte character encodings, respectively, do or do not have
multibyte character.
9 In no case will the int pointed to by status be set to a value greater than the
MB_CUR_MAX macro.
- Returns
+<b> Returns</b>
10 The wctomb_s function returns zero if successful, and a nonzero value if there was a
runtime-constraint violation or wc did not correspond to a valid multibyte character.
<a name="K.3.6.5" href="#K.3.6.5"><b> K.3.6.5 Multibyte/wide string conversion functions</b></a>
1 The behavior of the multibyte string functions is affected by the LC_CTYPE category of
the current locale.
<a name="K.3.6.5.1" href="#K.3.6.5.1"><b> K.3.6.5.1 The mbstowcs_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
errno_t mbstowcs_s(size_t * restrict retval,
wchar_t * restrict dst, rsize_t dstmax,
retval is not a null pointer, then mbstowcs_s sets *retval to (size_t)(-1). If
dst is not a null pointer and dstmax is greater than zero and less than RSIZE_MAX,
then mbstowcs_s sets dst[0] to the null wide character.
- Description
+<b> Description</b>
4 The mbstowcs_s function converts a sequence of multibyte characters that begins in
the initial shift state from the array pointed to by src into a sequence of corresponding
wide characters. If dst is not a null pointer, the converted characters are stored into the
array pointed to by dst. Conversion continues up to and including a terminating null
character, which is also stored. Conversion stops earlier in two cases: when a sequence of
-[<a name="#p607" href="p607">page 607</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p607" href="#p607">page 607</a>] (<a href="#Contents">Contents</a>)
bytes is encountered that does not form a valid multibyte character, or (if dst is not a
null pointer) when len wide characters have been stored into the array pointed to by
- dst.400) If dst is not a null pointer and no null wide character was stored into the array
+ dst.<sup><a href="#note400"><b>400)</b></a></sup> If dst is not a null pointer and no null wide character was stored into the array
pointed to by dst, then dst[len] is set to the null wide character. Each conversion
takes place as if by a call to the mbrtowc function.
5 Regardless of whether dst is or is not a null pointer, if the input conversion encounters a
characters successfully converted, not including the terminating null character (if any).
6 All elements following the terminating null wide character (if any) written by
mbstowcs_s in the array of dstmax wide characters pointed to by dst take
- unspecified values when mbstowcs_s returns.401)
+ unspecified values when mbstowcs_s returns.<sup><a href="#note401"><b>401)</b></a></sup>
7 If copying takes place between objects that overlap, the objects take on unspecified
values.
- Returns
+<b> Returns</b>
8 The mbstowcs_s function returns zero if no runtime-constraint violation and no
encoding error occurred. Otherwise, a nonzero value is returned.
<a name="K.3.6.5.2" href="#K.3.6.5.2"><b> K.3.6.5.2 The wcstombs_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #include <a href="#7.22"><stdlib.h></a>
errno_t wcstombs_s(size_t * restrict retval,
char * restrict dst, rsize_t dstmax,
- 400) Thus, the value of len is ignored if dst is a null pointer.
- 401) This allows an implementation to attempt converting the multibyte string before discovering a
+ <sup><a name="note400" href="#note400"><b>400)</b></a></sup> Thus, the value of len is ignored if dst is a null pointer.
+ <sup><a name="note401" href="#note401"><b>401)</b></a></sup> This allows an implementation to attempt converting the multibyte string before discovering a
terminating null character did not occur where required.
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#p608" href="p608">page 608</a>] (<a href="#Contents">Contents</a>)
+[<a name="
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3 If there is a runtime-constraint violation, then wcstombs_s does the following. If
retval is not a null pointer, then wcstombs_s sets *retval to (size_t)(-1). If
dst is not a null pointer and dstmax is greater than zero and less than RSIZE_MAX,
then wcstombs_s sets dst[0] to the null character.
- Description
+<b> Description</b>
4 The wcstombs_s function converts a sequence of wide characters from the array
pointed to by src into a sequence of corresponding multibyte characters that begins in
the initial shift state. If dst is not a null pointer, the converted characters are then stored
If the conversion stops without converting a null wide character and dst is not a null
pointer, then a null character is stored into the array pointed to by dst immediately
following any multibyte characters already stored. Each conversion takes place as if by a
- call to the wcrtomb function.402)
+ call to the wcrtomb function.<sup><a href="#note402"><b>402)</b></a></sup>
5 Regardless of whether dst is or is not a null pointer, if the input conversion encounters a
wide character that does not correspond to a valid multibyte character, an encoding error
occurs: the wcstombs_s function stores the value (size_t)(-1) into *retval.
any).
6 All elements following the terminating null character (if any) written by wcstombs_s
in the array of dstmax elements pointed to by dst take unspecified values when
- wcstombs_s returns.403)
+ wcstombs_s returns.<sup><a href="#note403"><b>403)</b></a></sup>
7 If copying takes place between objects that overlap, the objects take on unspecified
values.
- 402) If conversion stops because a terminating null wide character has been reached, the bytes stored
+ <sup><a name="note402" href="#note402"><b>402)</b></a></sup> If conversion stops because a terminating null wide character has been reached, the bytes stored
include those necessary to reach the initial shift state immediately before the null byte. However, if
the conversion stops before a terminating null wide character has been reached, the result will be null
terminated, but might not end in the initial shift state.
- 403) When len is not less than dstmax, the implementation might fill the array before discovering a
+ <sup><a name="note403" href="#note403"><b>403)</b></a></sup> When len is not less than dstmax, the implementation might fill the array before discovering a
runtime-constraint violation.
-[<a name="
#p609" href="p609">page 609</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p609" href="#p609">page 609</a>] (<a href="#Contents">Contents</a>)
- Returns
+<b> Returns</b>
8 The wcstombs_s function returns zero if no runtime-constraint violation and no
encoding error occurred. Otherwise, a nonzero value is returned.
<a name="K.3.7" href="#K.3.7"><b> K.3.7 String handling <string.h></b></a>
which is the type size_t.
<a name="K.3.7.1" href="#K.3.7.1"><b> K.3.7.1 Copying functions</b></a>
<a name="K.3.7.1.1" href="#K.3.7.1.1"><b> K.3.7.1.1 The memcpy_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
errno_t memcpy_s(void * restrict s1, rsize_t s1max,
3 If there is a runtime-constraint violation, the memcpy_s function stores zeros in the first
s1max characters of the object pointed to by s1 if s1 is not a null pointer and s1max is
not greater than RSIZE_MAX.
- Description
+<b> Description</b>
4 The memcpy_s function copies n characters from the object pointed to by s2 into the
object pointed to by s1.
- Returns
+<b> Returns</b>
5 The memcpy_s function returns zero if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
-
-
-
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+[<a name="p610" href="#p610">page 610</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.7.1.2" href="#K.3.7.1.2"><b> K.3.7.1.2 The memmove_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
errno_t memmove_s(void *s1, rsize_t s1max,
3 If there is a runtime-constraint violation, the memmove_s function stores zeros in the
first s1max characters of the object pointed to by s1 if s1 is not a null pointer and
s1max is not greater than RSIZE_MAX.
- Description
+<b> Description</b>
4 The memmove_s function copies n characters from the object pointed to by s2 into the
object pointed to by s1. This copying takes place as if the n characters from the object
pointed to by s2 are first copied into a temporary array of n characters that does not
overlap the objects pointed to by s1 or s2, and then the n characters from the temporary
array are copied into the object pointed to by s1.
- Returns
+<b> Returns</b>
5 The memmove_s function returns zero if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
<a name="K.3.7.1.3" href="#K.3.7.1.3"><b> K.3.7.1.3 The strcpy_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
errno_t strcpy_s(char * restrict s1,
greater than zero and not greater than RSIZE_MAX, then strcpy_s sets s1[0] to the
null character.
-[<a name="
#p611" href="p611">page 611</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p611" href="#p611">page 611</a>] (<a href="#Contents">Contents</a>)
- Description
+<b> Description</b>
4 The strcpy_s function copies the string pointed to by s2 (including the terminating
null character) into the array pointed to by s1.
5 All elements following the terminating null character (if any) written by strcpy_s in
the array of s1max characters pointed to by s1 take unspecified values when
- strcpy_s returns.404)
- Returns
-6 The strcpy_s function returns zero405) if there was no runtime-constraint violation.
+ strcpy_s returns.<sup><a href="#note404"><b>404)</b></a></sup>
+<b> Returns</b>
+6 The strcpy_s function returns zero<sup><a href="#note405"><b>405)</b></a></sup> if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
<a name="K.3.7.1.4" href="#K.3.7.1.4"><b> K.3.7.1.4 The strncpy_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
errno_t strncpy_s(char * restrict s1,
3 If there is a runtime-constraint violation, then if s1 is not a null pointer and s1max is
greater than zero and not greater than RSIZE_MAX, then strncpy_s sets s1[0] to the
null character.
- Description
+<b> Description</b>
4 The strncpy_s function copies not more than n successive characters (characters that
follow a null character are not copied) from the array pointed to by s2 to the array
pointed to by s1. If no null character was copied from s2, then s1[n] is set to a null
character.
- 404) This allows an implementation to copy characters from s2 to s1 while simultaneously checking if
+ <sup><a name="note404" href="#note404"><b>404)</b></a></sup> This allows an implementation to copy characters from s2 to s1 while simultaneously checking if
any of those characters are null. Such an approach might write a character to every element of s1
before discovering that the first element should be set to the null character.
- 405) A zero return value implies that all of the requested characters from the string pointed to by s2 fit
+ <sup><a name="note405" href="#note405"><b>405)</b></a></sup> A zero return value implies that all of the requested characters from the string pointed to by s2 fit
within the array pointed to by s1 and that the result in s1 is null terminated.
-[<a name="
#p612" href="p612">page 612</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p612" href="#p612">page 612</a>] (<a href="#Contents">Contents</a>)
5 All elements following the terminating null character (if any) written by strncpy_s in
the array of s1max characters pointed to by s1 take unspecified values when
- strncpy_s returns.406)
- Returns
-6 The strncpy_s function returns zero407) if there was no runtime-constraint violation.
+ strncpy_s returns.<sup><a href="#note406"><b>406)</b></a></sup>
+<b> Returns</b>
+6 The strncpy_s function returns zero<sup><a href="#note407"><b>407)</b></a></sup> if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
7 EXAMPLE 1 The strncpy_s function can be used to copy a string without the danger that the result
will not be null terminated or that characters will be written past the end of the destination array.
<a name="K.3.7.2" href="#K.3.7.2"><b> K.3.7.2 Concatenation functions</b></a>
<a name="K.3.7.2.1" href="#K.3.7.2.1"><b> K.3.7.2.1 The strcat_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
errno_t strcat_s(char * restrict s1,
- 406) This allows an implementation to copy characters from s2 to s1 while simultaneously checking if
+ <sup><a name="note406" href="#note406"><b>406)</b></a></sup> This allows an implementation to copy characters from s2 to s1 while simultaneously checking if
any of those characters are null. Such an approach might write a character to every element of s1
before discovering that the first element should be set to the null character.
- 407) A zero return value implies that all of the requested characters from the string pointed to by s2 fit
+ <sup><a name="note407" href="#note407"><b>407)</b></a></sup> A zero return value implies that all of the requested characters from the string pointed to by s2 fit
within the array pointed to by s1 and that the result in s1 is null terminated.
-[<a name="
#p613" href="p613">page 613</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p613" href="#p613">page 613</a>] (<a href="#Contents">Contents</a>)
3 Neither s1 nor s2 shall be a null pointer. s1max shall not be greater than RSIZE_MAX.
- s1max shall not equal zero. m shall not equal zero.408) m shall be greater than
+ s1max shall not equal zero. m shall not equal zero.<sup><a href="#note408"><b>408)</b></a></sup> m shall be greater than
strnlen_s(s2, m). Copying shall not take place between objects that overlap.
4 If there is a runtime-constraint violation, then if s1 is not a null pointer and s1max is
greater than zero and not greater than RSIZE_MAX, then strcat_s sets s1[0] to the
null character.
- Description
+<b> Description</b>
5 The strcat_s function appends a copy of the string pointed to by s2 (including the
terminating null character) to the end of the string pointed to by s1. The initial character
from s2 overwrites the null character at the end of s1.
6 All elements following the terminating null character (if any) written by strcat_s in
the array of s1max characters pointed to by s1 take unspecified values when
- strcat_s returns.409)
- Returns
-7 The strcat_s function returns zero410) if there was no runtime-constraint violation.
+ strcat_s returns.<sup><a href="#note409"><b>409)</b></a></sup>
+<b> Returns</b>
+7 The strcat_s function returns zero<sup><a href="#note410"><b>410)</b></a></sup> if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
<a name="K.3.7.2.2" href="#K.3.7.2.2"><b> K.3.7.2.2 The strncat_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
errno_t strncat_s(char * restrict s1,
2 Let m denote the value s1max - strnlen_s(s1, s1max) upon entry to
strncat_s.
3 Neither s1 nor s2 shall be a null pointer. Neither s1max nor n shall be greater than
- RSIZE_MAX. s1max shall not equal zero. m shall not equal zero.411) If n is not less
+ RSIZE_MAX. s1max shall not equal zero. m shall not equal zero.<sup><a href="#note411"><b>411)</b></a></sup> If n is not less
- 408) Zero means that s1 was not null terminated upon entry to strcat_s.
- 409) This allows an implementation to append characters from s2 to s1 while simultaneously checking if
+ <sup><a name="note408" href="#note408"><b>408)</b></a></sup> Zero means that s1 was not null terminated upon entry to strcat_s.
+ <sup><a name="note409" href="#note409"><b>409)</b></a></sup> This allows an implementation to append characters from s2 to s1 while simultaneously checking if
any of those characters are null. Such an approach might write a character to every element of s1
before discovering that the first element should be set to the null character.
- 410) A zero return value implies that all of the requested characters from the string pointed to by s2 were
+ <sup><a name="note410" href="#note410"><b>410)</b></a></sup> A zero return value implies that all of the requested characters from the string pointed to by s2 were
appended to the string pointed to by s1 and that the result in s1 is null terminated.
-[<a name="
#p614" href="p614">page 614</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p614" href="#p614">page 614</a>] (<a href="#Contents">Contents</a>)
than m, then m shall be greater than strnlen_s(s2, m). Copying shall not take
place between objects that overlap.
4 If there is a runtime-constraint violation, then if s1 is not a null pointer and s1max is
greater than zero and not greater than RSIZE_MAX, then strncat_s sets s1[0] to the
null character.
- Description
+<b> Description</b>
5 The strncat_s function appends not more than n successive characters (characters
that follow a null character are not copied) from the array pointed to by s2 to the end of
the string pointed to by s1. The initial character from s2 overwrites the null character at
a null character.
6 All elements following the terminating null character (if any) written by strncat_s in
the array of s1max characters pointed to by s1 take unspecified values when
- strncat_s returns.412)
- Returns
-7 The strncat_s function returns zero413) if there was no runtime-constraint violation.
+ strncat_s returns.<sup><a href="#note412"><b>412)</b></a></sup>
+<b> Returns</b>
+7 The strncat_s function returns zero<sup><a href="#note413"><b>413)</b></a></sup> if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
8 EXAMPLE 1 The strncat_s function can be used to copy a string without the danger that the result
will not be null terminated or that characters will be written past the end of the destination array.
- 411) Zero means that s1 was not null terminated upon entry to strncat_s.
- 412) This allows an implementation to append characters from s2 to s1 while simultaneously checking if
+ <sup><a name="note411" href="#note411"><b>411)</b></a></sup> Zero means that s1 was not null terminated upon entry to strncat_s.
+ <sup><a name="note412" href="#note412"><b>412)</b></a></sup> This allows an implementation to append characters from s2 to s1 while simultaneously checking if
any of those characters are null. Such an approach might write a character to every element of s1
before discovering that the first element should be set to the null character.
- 413) A zero return value implies that all of the requested characters from the string pointed to by s2 were
+ <sup><a name="note413" href="#note413"><b>413)</b></a></sup> A zero return value implies that all of the requested characters from the string pointed to by s2 were
appended to the string pointed to by s1 and that the result in s1 is null terminated.
-[<a name="
#p615" href="p615">page 615</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p615" href="#p615">page 615</a>] (<a href="#Contents">Contents</a>)
After the second call r2 will have the value zero and s2 will contain the sequence hello\0.
After the third call r3 will have a nonzero value and s3 will contain the sequence \0.
<a name="K.3.7.3" href="#K.3.7.3"><b> K.3.7.3 Search functions</b></a>
<a name="K.3.7.3.1" href="#K.3.7.3.1"><b> K.3.7.3.1 The strtok_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
char *strtok_s(char * restrict s1,
on subsequent calls.
3 If there is a runtime-constraint violation, the strtok_s function does not indirect
through the s1 or s2 pointers, and does not store a value in the object pointed to by ptr.
- Description
+<b> Description</b>
4 A sequence of calls to the strtok_s function breaks the string pointed to by s1 into a
sequence of tokens, each of which is delimited by a character from the string pointed to
by s2. The fourth argument points to a caller-provided char pointer into which the
that is not contained in the current separator string pointed to by s2. If no such character
is found, then there are no tokens in the string pointed to by s1 and the strtok_s
function returns a null pointer. If such a character is found, it is the start of the first token.
-[<a name="#p616" href="p616">page 616</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p616" href="#p616">page 616</a>] (<a href="#Contents">Contents</a>)
7 The strtok_s function then searches from there for the first character in s1 that is
contained in the current separator string. If no such character is found, the current token
to by ptr so that subsequent calls, with a null pointer for s1 and the unmodified pointer
value for ptr, shall start searching just past the element overwritten by a null character
(if any).
- Returns
+<b> Returns</b>
9 The strtok_s function returns a pointer to the first character of a token, or a null
pointer if there is no token or there is a runtime-constraint violation.
10 EXAMPLE
<a name="K.3.7.4" href="#K.3.7.4"><b> K.3.7.4 Miscellaneous functions</b></a>
<a name="K.3.7.4.1" href="#K.3.7.4.1"><b> K.3.7.4.1 The memset_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
errno_t memset_s(void *s, rsize_t smax, int c, rsize_t n)
greater than RSIZE_MAX, the memset_s function stores the value of c (converted to an
unsigned char) into each of the first smax characters of the object pointed to by s.
+[<a name="p617" href="#p617">page 617</a>] (<a href="#Contents">Contents</a>)
-
-[<a name="#p617" href="p617">page 617</a>] (<a href="#Contents">Contents</a>)
-
- Description
+<b> Description</b>
4 The memset_s function copies the value of c (converted to an unsigned char) into
each of the first n characters of the object pointed to by s. Unlike memset, any call to
the memset_s function shall be evaluated strictly according to the rules of the abstract
machine as described in (<a href="#5.1.2.3">5.1.2.3</a>). That is, any call to the memset_s function shall
assume that the memory indicated by s and n may be accessible in the future and thus
must contain the values indicated by c.
- Returns
+<b> Returns</b>
5 The memset_s function returns zero if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
<a name="K.3.7.4.2" href="#K.3.7.4.2"><b> K.3.7.4.2 The strerror_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
errno_t strerror_s(char *s, rsize_t maxsize,
maxsize shall not equal zero.
3 If there is a runtime-constraint violation, then the array (if any) pointed to by s is not
modified.
- Description
+<b> Description</b>
4 The strerror_s function maps the number in errnum to a locale-specific message
string. Typically, the values for errnum come from errno, but strerror_s shall
map any value of type int to a message.
from the string to the array pointed to by s and then s[maxsize-1] is set to the null
character. Then, if maxsize is greater than 3, then s[maxsize-2],
s[maxsize-3], and s[maxsize-4] are set to the character period (.).
- Returns
+<b> Returns</b>
7 The strerror_s function returns zero if the length of the desired string was less than
maxsize and there was no runtime-constraint violation. Otherwise, the strerror_s
function returns a nonzero value.
-[<a name="
#p618" href="p618">page 618</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p618" href="#p618">page 618</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.7.4.3" href="#K.3.7.4.3"><b> K.3.7.4.3 The strerrorlen_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
size_t strerrorlen_s(errno_t errnum);
- Description
+<b> Description</b>
2 The strerrorlen_s function calculates the length of the (untruncated) locale-specific
message string that the strerror_s function maps to errnum.
- Returns
+<b> Returns</b>
3 The strerrorlen_s function returns the number of characters (not including the null
character) in the full message string.
<a name="K.3.7.4.4" href="#K.3.7.4.4"><b> K.3.7.4.4 The strnlen_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
size_t strnlen_s(const char *s, size_t maxsize);
- Description
+<b> Description</b>
2 The strnlen_s function computes the length of the string pointed to by s.
- Returns
-3 If s is a null pointer,414) then the strnlen_s function returns zero.
+<b> Returns</b>
+3 If s is a null pointer,<sup><a href="#note414"><b>414)</b></a></sup> then the strnlen_s function returns zero.
4 Otherwise, the strnlen_s function returns the number of characters that precede the
terminating null character. If there is no null character in the first maxsize characters of
s then strnlen_s returns maxsize. At most the first maxsize characters of s shall
- 414) Note that the strnlen_s function has no runtime-constraints. This lack of runtime-constraints
+ <sup><a name="note414" href="#note414"><b>414)</b></a></sup> Note that the strnlen_s function has no runtime-constraints. This lack of runtime-constraints
along with the values returned for a null pointer or an unterminated string argument make
strnlen_s useful in algorithms that gracefully handle such exceptional data.
-[<a name="
#p619" href="p619">page 619</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p619" href="#p619">page 619</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.8" href="#K.3.8"><b> K.3.8 Date and time <time.h></b></a>
1 The header <a href="#7.26"><time.h></a> defines two types.
which is the type size_t.
<a name="K.3.8.1" href="#K.3.8.1"><b> K.3.8.1 Components of time</b></a>
1 A broken-down time is normalized if the values of the members of the tm structure are in
- their normal rages.415)
+ their normal rages.<sup><a href="#note415"><b>415)</b></a></sup>
<a name="K.3.8.2" href="#K.3.8.2"><b> K.3.8.2 Time conversion functions</b></a>
1 Like the strftime function, the asctime_s and ctime_s functions do not return a
pointer to a static object, and other library functions are permitted to call them.
<a name="K.3.8.2.1" href="#K.3.8.2.1"><b> K.3.8.2.1 The asctime_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.26"><time.h></a>
errno_t asctime_s(char *s, rsize_t maxsize,
3 If there is a runtime-constraint violation, there is no attempt to convert the time, and
s[0] is set to a null character if s is not a null pointer and maxsize is not zero and is
not greater than RSIZE_MAX.
- Description
+<b> Description</b>
4 The asctime_s function converts the normalized broken-down time in the structure
pointed to by timeptr into a 26 character (including the null character) string in the
-
415) The normal ranges are defined in <a href="#7.26.1">7.26.1</a>.
+
<sup><a name="note415" href="#note415"><b>415)</b></a></sup> The normal ranges are defined in <a href="#7.26.1">7.26.1</a>.
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+[<a name="
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form
Sun Sep 16 01:03:52 1973\n\0
The strftime function allows more flexible formatting and supports locale-specific
behavior. If you do not require the exact form of the result string produced by the
asctime_s function, consider using the strftime function instead.
- Returns
+<b> Returns</b>
5 The asctime_s function returns zero if the time was successfully converted and stored
into the array pointed to by s. Otherwise, it returns a nonzero value.
-[<a name="#p621" href="p621">page 621</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p621" href="#p621">page 621</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.8.2.2" href="#K.3.8.2.2"><b> K.3.8.2.2 The ctime_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.26"><time.h></a>
errno_t ctime_s(char *s, rsize_t maxsize,
shall not be greater than RSIZE_MAX.
3 If there is a runtime-constraint violation, s[0] is set to a null character if s is not a null
pointer and maxsize is not equal zero and is not greater than RSIZE_MAX.
- Description
+<b> Description</b>
4 The ctime_s function converts the calendar time pointed to by timer to local time in
the form of a string. It is equivalent to
asctime_s(s, maxsize, localtime_s(timer))
The strftime function allows more flexible formatting and supports locale-specific
behavior. If you do not require the exact form of the result string produced by the
ctime_s function, consider using the strftime function instead.
- Returns
+<b> Returns</b>
5 The ctime_s function returns zero if the time was successfully converted and stored
into the array pointed to by s. Otherwise, it returns a nonzero value.
<a name="K.3.8.2.3" href="#K.3.8.2.3"><b> K.3.8.2.3 The gmtime_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.26"><time.h></a>
struct tm *gmtime_s(const time_t * restrict timer,
Runtime-constraints
2 Neither timer nor result shall be a null pointer.
3 If there is a runtime-constraint violation, there is no attempt to convert the time.
- Description
+<b> Description</b>
4 The gmtime_s function converts the calendar time pointed to by timer into a broken-
down time, expressed as UTC. The broken-down time is stored in the structure pointed
-[<a name="#p622" href="p622">page 622</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p622" href="#p622">page 622</a>] (<a href="#Contents">Contents</a>)
to by result.
- Returns
+<b> Returns</b>
5 The gmtime_s function returns result, or a null pointer if the specified time cannot
be converted to UTC or there is a runtime-constraint violation.
<a name="K.3.8.2.4" href="#K.3.8.2.4"><b> K.3.8.2.4 The localtime_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.26"><time.h></a>
struct tm *localtime_s(const time_t * restrict timer,
Runtime-constraints
2 Neither timer nor result shall be a null pointer.
3 If there is a runtime-constraint violation, there is no attempt to convert the time.
- Description
+<b> Description</b>
4 The localtime_s function converts the calendar time pointed to by timer into a
broken-down time, expressed as local time. The broken-down time is stored in the
structure pointed to by result.
- Returns
+<b> Returns</b>
5 The localtime_s function returns result, or a null pointer if the specified time
cannot be converted to local time or there is a runtime-constraint violation.
<a name="K.3.9" href="#K.3.9"><b> K.3.9 Extended multibyte and wide character utilities <wchar.h></b></a>
subclause causes copying to take place between objects that overlap, the objects take on
unspecified values.
-
-
-
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+[<a name="p623" href="#p623">page 623</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.9.1" href="#K.3.9.1"><b> K.3.9.1 Formatted wide character input/output functions</b></a>
<a name="K.3.9.1.1" href="#K.3.9.1.1"><b> K.3.9.1.1 The fwprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
int fwprintf_s(FILE * restrict stream,
const wchar_t * restrict format, ...);
Runtime-constraints
-2 Neither stream nor format shall be a null pointer. The %n specifier416) (modified or
+2 Neither stream nor format shall be a null pointer. The %n specifier<sup><a href="#note416"><b>416)</b></a></sup> (modified or
not by flags, field width, or precision) shall not appear in the wide string pointed to by
format. Any argument to fwprintf_s corresponding to a %s specifier shall not be a
null pointer.
3 If there is a runtime-constraint violation, the fwprintf_s function does not attempt to
produce further output, and it is unspecified to what extent fwprintf_s produced
output before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The fwprintf_s function is equivalent to the fwprintf function except for the
explicit runtime-constraints listed above.
- Returns
+<b> Returns</b>
5 The fwprintf_s function returns the number of wide characters transmitted, or a
negative value if an output error, encoding error, or runtime-constraint violation occurred.
<a name="K.3.9.1.2" href="#K.3.9.1.2"><b> K.3.9.1.2 The fwscanf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
order to store converted input shall not be a null pointer.
- 416) It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
+ <sup><a name="note416" href="#note416"><b>416)</b></a></sup> It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
string pointed at by format when those wide characters are not a interpreted as a %n specifier. For
example, if the entire format string was L"%%n".
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+[<a name="
p624" href="#p624">page 624</a>] (<a href="#Contents">Contents</a>)
3 If there is a runtime-constraint violation, the fwscanf_s function does not attempt to
perform further input, and it is unspecified to what extent fwscanf_s performed input
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The fwscanf_s function is equivalent to fwscanf except that the c, s, and [
conversion specifiers apply to a pair of arguments (unless assignment suppression is
indicated by a *). The first of these arguments is the same as for fwscanf. That
argument is immediately followed in the argument list by the second argument, which has
type size_t and gives the number of elements in the array pointed to by the first
argument of the pair. If the first argument points to a scalar object, it is considered to be
- an array of one element.417)
+ an array of one element.<sup><a href="#note417"><b>417)</b></a></sup>
5 A matching failure occurs if the number of elements in a receiving object is insufficient to
hold the converted input (including any trailing null character).
- Returns
+<b> Returns</b>
6 The fwscanf_s function returns the value of the macro EOF if an input failure occurs
before any conversion or if there is a runtime-constraint violation. Otherwise, the
fwscanf_s function returns the number of input items assigned, which can be fewer
than provided for, or even zero, in the event of an early matching failure.
<a name="K.3.9.1.3" href="#K.3.9.1.3"><b> K.3.9.1.3 The snwprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
int snwprintf_s(wchar_t * restrict s,
const wchar_t * restrict format, ...);
Runtime-constraints
2 Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
- than RSIZE_MAX. The %n specifier418) (modified or not by flags, field width, or
+ than RSIZE_MAX. The %n specifier<sup><a href="#note418"><b>418)</b></a></sup> (modified or not by flags, field width, or
- 417) If the format is known at translation time, an implementation may issue a diagnostic for any argument
+ <sup><a name="note417" href="#note417"><b>417)</b></a></sup> If the format is known at translation time, an implementation may issue a diagnostic for any argument
used to store the result from a c, s, or [ conversion specifier if that argument is not followed by an
argument of a type compatible with rsize_t. A limited amount of checking may be done if even if
the format is not known at translation time. For example, an implementation may issue a diagnostic
diagnostic could flag any non-pointer argument following format that did not have a type
compatible with rsize_t.
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+[<a name="
p625" href="#p625">page 625</a>] (<a href="#Contents">Contents</a>)
precision) shall not appear in the wide string pointed to by format. Any argument to
snwprintf_s corresponding to a %s specifier shall not be a null pointer. No encoding
3 If there is a runtime-constraint violation, then if s is not a null pointer and n is greater
than zero and less than RSIZE_MAX, then the snwprintf_s function sets s[0] to the
null wide character.
- Description
+<b> Description</b>
4 The snwprintf_s function is equivalent to the swprintf function except for the
explicit runtime-constraints listed above.
5 The snwprintf_s function, unlike swprintf_s, will truncate the result to fit within
the array pointed to by s.
- Returns
+<b> Returns</b>
6 The snwprintf_s function returns the number of wide characters that would have
been written had n been sufficiently large, not counting the terminating wide null
character, or a negative value if a runtime-constraint violation occurred. Thus, the null-
terminated output has been completely written if and only if the returned value is
nonnegative and less than n.
<a name="K.3.9.1.4" href="#K.3.9.1.4"><b> K.3.9.1.4 The swprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
int swprintf_s(wchar_t * restrict s, rsize_t n,
2 Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
than RSIZE_MAX. The number of wide characters (including the trailing null) required
for the result to be written to the array pointed to by s shall not be greater than n. The %n
- specifier419) (modified or not by flags, field width, or precision) shall not appear in the
+ specifier<sup><a href="#note419"><b>419)</b></a></sup> (modified or not by flags, field width, or precision) shall not appear in the
wide string pointed to by format. Any argument to swprintf_s corresponding to a
%s specifier shall not be a null pointer. No encoding error shall occur.
- 418) It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
+ <sup><a name="note418" href="#note418"><b>418)</b></a></sup> It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
string pointed at by format when those wide characters are not a interpreted as a %n specifier. For
example, if the entire format string was L"%%n".
- 419) It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
+ <sup><a name="note419" href="#note419"><b>419)</b></a></sup> It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
string pointed at by format when those wide characters are not a interpreted as a %n specifier. For
example, if the entire format string was L"%%n".
-[<a name="
#p626" href="p626">page 626</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p626" href="#p626">page 626</a>] (<a href="#Contents">Contents</a>)
3 If there is a runtime-constraint violation, then if s is not a null pointer and n is greater
than zero and less than RSIZE_MAX, then the swprintf_s function sets s[0] to the
null wide character.
- Description
+<b> Description</b>
4 The swprintf_s function is equivalent to the swprintf function except for the
explicit runtime-constraints listed above.
5 The swprintf_s function, unlike snwprintf_s, treats a result too big for the array
pointed to by s as a runtime-constraint violation.
- Returns
+<b> Returns</b>
6 If no runtime-constraint violation occurred, the swprintf_s function returns the
number of wide characters written in the array, not counting the terminating null wide
character. If an encoding error occurred or if n or more wide characters are requested to
be written, swprintf_s returns a negative value. If any other runtime-constraint
violation occurred, swprintf_s returns zero.
<a name="K.3.9.1.5" href="#K.3.9.1.5"><b> K.3.9.1.5 The swscanf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
int swscanf_s(const wchar_t * restrict s,
3 If there is a runtime-constraint violation, the swscanf_s function does not attempt to
perform further input, and it is unspecified to what extent swscanf_s performed input
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The swscanf_s function is equivalent to fwscanf_s, except that the argument s
specifies a wide string from which the input is to be obtained, rather than from a stream.
Reaching the end of the wide string is equivalent to encountering end-of-file for the
fwscanf_s function.
- Returns
+<b> Returns</b>
5 The swscanf_s function returns the value of the macro EOF if an input failure occurs
before any conversion or if there is a runtime-constraint violation. Otherwise, the
swscanf_s function returns the number of input items assigned, which can be fewer
than provided for, or even zero, in the event of an early matching failure.
-[<a name="#p627" href="p627">page 627</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p627" href="#p627">page 627</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.9.1.6" href="#K.3.9.1.6"><b> K.3.9.1.6 The vfwprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
const wchar_t * restrict format,
va_list arg);
Runtime-constraints
-2 Neither stream nor format shall be a null pointer. The %n specifier420) (modified or
+2 Neither stream nor format shall be a null pointer. The %n specifier<sup><a href="#note420"><b>420)</b></a></sup> (modified or
not by flags, field width, or precision) shall not appear in the wide string pointed to by
format. Any argument to vfwprintf_s corresponding to a %s specifier shall not be
a null pointer.
3 If there is a runtime-constraint violation, the vfwprintf_s function does not attempt
to produce further output, and it is unspecified to what extent vfwprintf_s produced
output before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The vfwprintf_s function is equivalent to the vfwprintf function except for the
explicit runtime-constraints listed above.
- Returns
+<b> Returns</b>
5 The vfwprintf_s function returns the number of wide characters transmitted, or a
negative value if an output error, encoding error, or runtime-constraint violation occurred.
<a name="K.3.9.1.7" href="#K.3.9.1.7"><b> K.3.9.1.7 The vfwscanf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
- 420) It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
+ <sup><a name="note420" href="#note420"><b>420)</b></a></sup> It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
string pointed at by format when those wide characters are not a interpreted as a %n specifier. For
example, if the entire format string was L"%%n".
-[<a name="
#p628" href="p628">page 628</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p628" href="#p628">page 628</a>] (<a href="#Contents">Contents</a>)
Runtime-constraints
2 Neither stream nor format shall be a null pointer. Any argument indirected though in
3 If there is a runtime-constraint violation, the vfwscanf_s function does not attempt to
perform further input, and it is unspecified to what extent vfwscanf_s performed input
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The vfwscanf_s function is equivalent to fwscanf_s, with the variable argument
list replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vfwscanf_s function does not invoke the
- va_end macro.421)
- Returns
+ va_end macro.<sup><a href="#note421"><b>421)</b></a></sup>
+<b> Returns</b>
5 The vfwscanf_s function returns the value of the macro EOF if an input failure occurs
before any conversion or if there is a runtime-constraint violation. Otherwise, the
vfwscanf_s function returns the number of input items assigned, which can be fewer
than provided for, or even zero, in the event of an early matching failure.
<a name="K.3.9.1.8" href="#K.3.9.1.8"><b> K.3.9.1.8 The vsnwprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.28"><wchar.h></a>
va_list arg);
Runtime-constraints
2 Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
- than RSIZE_MAX. The %n specifier422) (modified or not by flags, field width, or
+ than RSIZE_MAX. The %n specifier<sup><a href="#note422"><b>422)</b></a></sup> (modified or not by flags, field width, or
precision) shall not appear in the wide string pointed to by format. Any argument to
vsnwprintf_s corresponding to a %s specifier shall not be a null pointer. No
encoding error shall occur.
- 421) As the functions vfwscanf_s, vwscanf_s, and vswscanf_s invoke the va_arg macro, the
+ <sup><a name="note421" href="#note421"><b>421)</b></a></sup> As the functions vfwscanf_s, vwscanf_s, and vswscanf_s invoke the va_arg macro, the
value of arg after the return is indeterminate.
- 422) It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
+ <sup><a name="note422" href="#note422"><b>422)</b></a></sup> It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
string pointed at by format when those wide characters are not a interpreted as a %n specifier. For
example, if the entire format string was L"%%n".
-[<a name="
#p629" href="p629">page 629</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p629" href="#p629">page 629</a>] (<a href="#Contents">Contents</a>)
3 If there is a runtime-constraint violation, then if s is not a null pointer and n is greater
than zero and less than RSIZE_MAX, then the vsnwprintf_s function sets s[0] to
the null wide character.
- Description
+<b> Description</b>
4 The vsnwprintf_s function is equivalent to the vswprintf function except for the
explicit runtime-constraints listed above.
5 The vsnwprintf_s function, unlike vswprintf_s, will truncate the result to fit
within the array pointed to by s.
- Returns
+<b> Returns</b>
6 The vsnwprintf_s function returns the number of wide characters that would have
been written had n been sufficiently large, not counting the terminating null character, or
a negative value if a runtime-constraint violation occurred. Thus, the null-terminated
output has been completely written if and only if the returned value is nonnegative and
less than n.
<a name="K.3.9.1.9" href="#K.3.9.1.9"><b> K.3.9.1.9 The vswprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.28"><wchar.h></a>
2 Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
than RSIZE_MAX. The number of wide characters (including the trailing null) required
for the result to be written to the array pointed to by s shall not be greater than n. The %n
- specifier423) (modified or not by flags, field width, or precision) shall not appear in the
+ specifier<sup><a href="#note423"><b>423)</b></a></sup> (modified or not by flags, field width, or precision) shall not appear in the
wide string pointed to by format. Any argument to vswprintf_s corresponding to a
%s specifier shall not be a null pointer. No encoding error shall occur.
3 If there is a runtime-constraint violation, then if s is not a null pointer and n is greater
than zero and less than RSIZE_MAX, then the vswprintf_s function sets s[0] to the
null wide character.
- 423) It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
+ <sup><a name="note423" href="#note423"><b>423)</b></a></sup> It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
string pointed at by format when those wide characters are not a interpreted as a %n specifier. For
example, if the entire format string was L"%%n".
-[<a name="
#p630" href="p630">page 630</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p630" href="#p630">page 630</a>] (<a href="#Contents">Contents</a>)
- Description
+<b> Description</b>
4 The vswprintf_s function is equivalent to the vswprintf function except for the
explicit runtime-constraints listed above.
5 The vswprintf_s function, unlike vsnwprintf_s, treats a result too big for the
array pointed to by s as a runtime-constraint violation.
- Returns
+<b> Returns</b>
6 If no runtime-constraint violation occurred, the vswprintf_s function returns the
number of wide characters written in the array, not counting the terminating null wide
character. If an encoding error occurred or if n or more wide characters are requested to
be written, vswprintf_s returns a negative value. If any other runtime-constraint
violation occurred, vswprintf_s returns zero.
<a name="K.3.9.1.10" href="#K.3.9.1.10"><b> K.3.9.1.10 The vswscanf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.28"><wchar.h></a>
3 If there is a runtime-constraint violation, the vswscanf_s function does not attempt to
perform further input, and it is unspecified to what extent vswscanf_s performed input
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The vswscanf_s function is equivalent to swscanf_s, with the variable argument
list replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vswscanf_s function does not invoke the
- va_end macro.424)
+ va_end macro.<sup><a href="#note424"><b>424)</b></a></sup>
- 424) As the functions vfwscanf_s, vwscanf_s, and vswscanf_s invoke the va_arg macro, the
+ <sup><a name="note424" href="#note424"><b>424)</b></a></sup> As the functions vfwscanf_s, vwscanf_s, and vswscanf_s invoke the va_arg macro, the
value of arg after the return is indeterminate.
-[<a name="
#p631" href="p631">page 631</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p631" href="#p631">page 631</a>] (<a href="#Contents">Contents</a>)
- Returns
+<b> Returns</b>
5 The vswscanf_s function returns the value of the macro EOF if an input failure occurs
before any conversion or if there is a runtime-constraint violation. Otherwise, the
vswscanf_s function returns the number of input items assigned, which can be fewer
than provided for, or even zero, in the event of an early matching failure.
<a name="K.3.9.1.11" href="#K.3.9.1.11"><b> K.3.9.1.11 The vwprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.28"><wchar.h></a>
int vwprintf_s(const wchar_t * restrict format,
va_list arg);
Runtime-constraints
-2 format shall not be a null pointer. The %n specifier425) (modified or not by flags, field
+2 format shall not be a null pointer. The %n specifier<sup><a href="#note425"><b>425)</b></a></sup> (modified or not by flags, field
width, or precision) shall not appear in the wide string pointed to by format. Any
argument to vwprintf_s corresponding to a %s specifier shall not be a null pointer.
3 If there is a runtime-constraint violation, the vwprintf_s function does not attempt to
produce further output, and it is unspecified to what extent vwprintf_s produced
output before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The vwprintf_s function is equivalent to the vwprintf function except for the
explicit runtime-constraints listed above.
- Returns
+<b> Returns</b>
5 The vwprintf_s function returns the number of wide characters transmitted, or a
negative value if an output error, encoding error, or runtime-constraint violation occurred.
- 425) It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
+ <sup><a name="note425" href="#note425"><b>425)</b></a></sup> It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
string pointed at by format when those wide characters are not a interpreted as a %n specifier. For
example, if the entire format string was L"%%n".
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+[<a name="
p632" href="#p632">page 632</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.9.1.12" href="#K.3.9.1.12"><b> K.3.9.1.12 The vwscanf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.28"><wchar.h></a>
3 If there is a runtime-constraint violation, the vwscanf_s function does not attempt to
perform further input, and it is unspecified to what extent vwscanf_s performed input
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The vwscanf_s function is equivalent to wscanf_s, with the variable argument list
replaced by arg, which shall have been initialized by the va_start macro (and
possibly subsequent va_arg calls). The vwscanf_s function does not invoke the
- va_end macro.426)
- Returns
+ va_end macro.<sup><a href="#note426"><b>426)</b></a></sup>
+<b> Returns</b>
5 The vwscanf_s function returns the value of the macro EOF if an input failure occurs
before any conversion or if there is a runtime-constraint violation. Otherwise, the
vwscanf_s function returns the number of input items assigned, which can be fewer
than provided for, or even zero, in the event of an early matching failure.
<a name="K.3.9.1.13" href="#K.3.9.1.13"><b> K.3.9.1.13 The wprintf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
int wprintf_s(const wchar_t * restrict format, ...);
Runtime-constraints
-2 format shall not be a null pointer. The %n specifier427) (modified or not by flags, field
+2 format shall not be a null pointer. The %n specifier<sup><a href="#note427"><b>427)</b></a></sup> (modified or not by flags, field
- 426) As the functions vfwscanf_s, vwscanf_s, and vswscanf_s invoke the va_arg macro, the
+ <sup><a name="note426" href="#note426"><b>426)</b></a></sup> As the functions vfwscanf_s, vwscanf_s, and vswscanf_s invoke the va_arg macro, the
value of arg after the return is indeterminate.
- 427) It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
+ <sup><a name="note427" href="#note427"><b>427)</b></a></sup> It is not a runtime-constraint violation for the wide characters %n to appear in sequence in the wide
string pointed at by format when those wide characters are not a interpreted as a %n specifier. For
example, if the entire format string was L"%%n".
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+[<a name="
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width, or precision) shall not appear in the wide string pointed to by format. Any
argument to wprintf_s corresponding to a %s specifier shall not be a null pointer.
3 If there is a runtime-constraint violation, the wprintf_s function does not attempt to
produce further output, and it is unspecified to what extent wprintf_s produced output
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The wprintf_s function is equivalent to the wprintf function except for the explicit
runtime-constraints listed above.
- Returns
+<b> Returns</b>
5 The wprintf_s function returns the number of wide characters transmitted, or a
negative value if an output error, encoding error, or runtime-constraint violation occurred.
<a name="K.3.9.1.14" href="#K.3.9.1.14"><b> K.3.9.1.14 The wscanf_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
int wscanf_s(const wchar_t * restrict format, ...);
3 If there is a runtime-constraint violation, the wscanf_s function does not attempt to
perform further input, and it is unspecified to what extent wscanf_s performed input
before discovering the runtime-constraint violation.
- Description
+<b> Description</b>
4 The wscanf_s function is equivalent to fwscanf_s with the argument stdin
interposed before the arguments to wscanf_s.
- Returns
+<b> Returns</b>
5 The wscanf_s function returns the value of the macro EOF if an input failure occurs
before any conversion or if there is a runtime-constraint violation. Otherwise, the
wscanf_s function returns the number of input items assigned, which can be fewer than
provided for, or even zero, in the event of an early matching failure.
-
-
-
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+[<a name="p634" href="#p634">page 634</a>] (<a href="#Contents">Contents</a>)
<a name="K.3.9.2" href="#K.3.9.2"><b> K.3.9.2 General wide string utilities</b></a>
<a name="K.3.9.2.1" href="#K.3.9.2.1"><b> K.3.9.2.1 Wide string copying functions</b></a>
<a name="K.3.9.2.1.1" href="#K.3.9.2.1.1"><b> K.3.9.2.1.1 The wcscpy_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
errno_t wcscpy_s(wchar_t * restrict s1,
3 If there is a runtime-constraint violation, then if s1 is not a null pointer and s1max is
greater than zero and not greater than RSIZE_MAX, then wcscpy_s sets s1[0] to the
null wide character.
- Description
+<b> Description</b>
4 The wcscpy_s function copies the wide string pointed to by s2 (including the
terminating null wide character) into the array pointed to by s1.
5 All elements following the terminating null wide character (if any) written by
wcscpy_s in the array of s1max wide characters pointed to by s1 take unspecified
- values when wcscpy_s returns.428)
- Returns
-6 The wcscpy_s function returns zero429) if there was no runtime-constraint violation.
+ values when wcscpy_s returns.<sup><a href="#note428"><b>428)</b></a></sup>
+<b> Returns</b>
+6 The wcscpy_s function returns zero<sup><a href="#note429"><b>429)</b></a></sup> if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
- 428) This allows an implementation to copy wide characters from s2 to s1 while simultaneously checking
+ <sup><a name="note428" href="#note428"><b>428)</b></a></sup> This allows an implementation to copy wide characters from s2 to s1 while simultaneously checking
if any of those wide characters are null. Such an approach might write a wide character to every
element of s1 before discovering that the first element should be set to the null wide character.
- 429) A zero return value implies that all of the requested wide characters from the string pointed to by s2
+ <sup><a name="note429" href="#note429"><b>429)</b></a></sup> A zero return value implies that all of the requested wide characters from the string pointed to by s2
fit within the array pointed to by s1 and that the result in s1 is null terminated.
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<a name="K.3.9.2.1.2" href="#K.3.9.2.1.2"><b> K.3.9.2.1.2 The wcsncpy_s function</b></a>
- Synopsis
+<b> Synopsis</b>
7 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
errno_t wcsncpy_s(wchar_t * restrict s1,
9 If there is a runtime-constraint violation, then if s1 is not a null pointer and s1max is
greater than zero and not greater than RSIZE_MAX, then wcsncpy_s sets s1[0] to the
null wide character.
- Description
+<b> Description</b>
10 The wcsncpy_s function copies not more than n successive wide characters (wide
characters that follow a null wide character are not copied) from the array pointed to by
s2 to the array pointed to by s1. If no null wide character was copied from s2, then
s1[n] is set to a null wide character.
11 All elements following the terminating null wide character (if any) written by
wcsncpy_s in the array of s1max wide characters pointed to by s1 take unspecified
- values when wcsncpy_s returns.430)
- Returns
-12 The wcsncpy_s function returns zero431) if there was no runtime-constraint violation.
+ values when wcsncpy_s returns.<sup><a href="#note430"><b>430)</b></a></sup>
+<b> Returns</b>
+12 The wcsncpy_s function returns zero<sup><a href="#note431"><b>431)</b></a></sup> if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
13 EXAMPLE 1 The wcsncpy_s function can be used to copy a wide string without the danger that the
result will not be null terminated or that wide characters will be written past the end of the destination
- 430) This allows an implementation to copy wide characters from s2 to s1 while simultaneously checking
+ <sup><a name="note430" href="#note430"><b>430)</b></a></sup> This allows an implementation to copy wide characters from s2 to s1 while simultaneously checking
if any of those wide characters are null. Such an approach might write a wide character to every
element of s1 before discovering that the first element should be set to the null wide character.
- 431) A zero return value implies that all of the requested wide characters from the string pointed to by s2
+ <sup><a name="note431" href="#note431"><b>431)</b></a></sup> A zero return value implies that all of the requested wide characters from the string pointed to by s2
fit within the array pointed to by s1 and that the result in s1 is null terminated.
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#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
The third call will assign to r3 the value zero and to dst3 the sequence of wide characters good\0.
<a name="K.3.9.2.1.3" href="#K.3.9.2.1.3"><b> K.3.9.2.1.3 The wmemcpy_s function</b></a>
- Synopsis
+<b> Synopsis</b>
14 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
errno_t wmemcpy_s(wchar_t * restrict s1,
16 If there is a runtime-constraint violation, the wmemcpy_s function stores zeros in the
first s1max wide characters of the object pointed to by s1 if s1 is not a null pointer and
s1max is not greater than RSIZE_MAX.
- Description
+<b> Description</b>
17 The wmemcpy_s function copies n successive wide characters from the object pointed
to by s2 into the object pointed to by s1.
- Returns
+<b> Returns</b>
18 The wmemcpy_s function returns zero if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
-
-
-
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<a name="K.3.9.2.1.4" href="#K.3.9.2.1.4"><b> K.3.9.2.1.4 The wmemmove_s function</b></a>
- Synopsis
+<b> Synopsis</b>
19 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
errno_t wmemmove_s(wchar_t *s1, rsize_t s1max,
21 If there is a runtime-constraint violation, the wmemmove_s function stores zeros in the
first s1max wide characters of the object pointed to by s1 if s1 is not a null pointer and
s1max is not greater than RSIZE_MAX.
- Description
+<b> Description</b>
22 The wmemmove_s function copies n successive wide characters from the object pointed
to by s2 into the object pointed to by s1. This copying takes place as if the n wide
characters from the object pointed to by s2 are first copied into a temporary array of n
wide characters that does not overlap the objects pointed to by s1 or s2, and then the n
wide characters from the temporary array are copied into the object pointed to by s1.
- Returns
+<b> Returns</b>
23 The wmemmove_s function returns zero if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
<a name="K.3.9.2.2" href="#K.3.9.2.2"><b> K.3.9.2.2 Wide string concatenation functions</b></a>
<a name="K.3.9.2.2.1" href="#K.3.9.2.2.1"><b> K.3.9.2.2.1 The wcscat_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
errno_t wcscat_s(wchar_t * restrict s1,
2 Let m denote the value s1max - wcsnlen_s(s1, s1max) upon entry to
wcscat_s.
3 Neither s1 nor s2 shall be a null pointer. s1max shall not be greater than RSIZE_MAX.
- s1max shall not equal zero. m shall not equal zero.432) m shall be greater than
+ s1max shall not equal zero. m shall not equal zero.<sup><a href="#note432"><b>432)</b></a></sup> m shall be greater than
wcsnlen_s(s2, m). Copying shall not take place between objects that overlap.
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4 If there is a runtime-constraint violation, then if s1 is not a null pointer and s1max is
greater than zero and not greater than RSIZE_MAX, then wcscat_s sets s1[0] to the
null wide character.
- Description
+<b> Description</b>
5 The wcscat_s function appends a copy of the wide string pointed to by s2 (including
the terminating null wide character) to the end of the wide string pointed to by s1. The
initial wide character from s2 overwrites the null wide character at the end of s1.
6 All elements following the terminating null wide character (if any) written by
wcscat_s in the array of s1max wide characters pointed to by s1 take unspecified
- values when wcscat_s returns.433)
- Returns
-7 The wcscat_s function returns zero434) if there was no runtime-constraint violation.
+ values when wcscat_s returns.<sup><a href="#note433"><b>433)</b></a></sup>
+<b> Returns</b>
+7 The wcscat_s function returns zero<sup><a href="#note434"><b>434)</b></a></sup> if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
<a name="K.3.9.2.2.2" href="#K.3.9.2.2.2"><b> K.3.9.2.2.2 The wcsncat_s function</b></a>
- Synopsis
+<b> Synopsis</b>
8 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
errno_t wcsncat_s(wchar_t * restrict s1,
9 Let m denote the value s1max - wcsnlen_s(s1, s1max) upon entry to
wcsncat_s.
10 Neither s1 nor s2 shall be a null pointer. Neither s1max nor n shall be greater than
- RSIZE_MAX. s1max shall not equal zero. m shall not equal zero.435) If n is not less
+ RSIZE_MAX. s1max shall not equal zero. m shall not equal zero.<sup><a href="#note435"><b>435)</b></a></sup> If n is not less
than m, then m shall be greater than wcsnlen_s(s2, m). Copying shall not take
place between objects that overlap.
- 432) Zero means that s1 was not null terminated upon entry to wcscat_s.
- 433) This allows an implementation to append wide characters from s2 to s1 while simultaneously
+ <sup><a name="note432" href="#note432"><b>432)</b></a></sup> Zero means that s1 was not null terminated upon entry to wcscat_s.
+ <sup><a name="note433" href="#note433"><b>433)</b></a></sup> This allows an implementation to append wide characters from s2 to s1 while simultaneously
checking if any of those wide characters are null. Such an approach might write a wide character to
every element of s1 before discovering that the first element should be set to the null wide character.
- 434) A zero return value implies that all of the requested wide characters from the wide string pointed to by
+ <sup><a name="note434" href="#note434"><b>434)</b></a></sup> A zero return value implies that all of the requested wide characters from the wide string pointed to by
s2 were appended to the wide string pointed to by s1 and that the result in s1 is null terminated.
- 435) Zero means that s1 was not null terminated upon entry to wcsncat_s.
+ <sup><a name="note435" href="#note435"><b>435)</b></a></sup> Zero means that s1 was not null terminated upon entry to wcsncat_s.
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11 If there is a runtime-constraint violation, then if s1 is not a null pointer and s1max is
greater than zero and not greater than RSIZE_MAX, then wcsncat_s sets s1[0] to the
null wide character.
- Description
+<b> Description</b>
12 The wcsncat_s function appends not more than n successive wide characters (wide
characters that follow a null wide character are not copied) from the array pointed to by
s2 to the end of the wide string pointed to by s1. The initial wide character from s2
from s2, then s1[s1max-m+n] is set to a null wide character.
13 All elements following the terminating null wide character (if any) written by
wcsncat_s in the array of s1max wide characters pointed to by s1 take unspecified
- values when wcsncat_s returns.436)
- Returns
-14 The wcsncat_s function returns zero437) if there was no runtime-constraint violation.
+ values when wcsncat_s returns.<sup><a href="#note436"><b>436)</b></a></sup>
+<b> Returns</b>
+14 The wcsncat_s function returns zero<sup><a href="#note437"><b>437)</b></a></sup> if there was no runtime-constraint violation.
Otherwise, a nonzero value is returned.
15 EXAMPLE 1 The wcsncat_s function can be used to copy a wide string without the danger that the
result will not be null terminated or that wide characters will be written past the end of the destination
- 436) This allows an implementation to append wide characters from s2 to s1 while simultaneously
+ <sup><a name="note436" href="#note436"><b>436)</b></a></sup> This allows an implementation to append wide characters from s2 to s1 while simultaneously
checking if any of those wide characters are null. Such an approach might write a wide character to
every element of s1 before discovering that the first element should be set to the null wide character.
- 437) A zero return value implies that all of the requested wide characters from the wide string pointed to by
+ <sup><a name="note437" href="#note437"><b>437)</b></a></sup> A zero return value implies that all of the requested wide characters from the wide string pointed to by
s2 were appended to the wide string pointed to by s1 and that the result in s1 is null terminated.
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<a name="K.3.9.2.3" href="#K.3.9.2.3"><b> K.3.9.2.3 Wide string search functions</b></a>
<a name="K.3.9.2.3.1" href="#K.3.9.2.3.1"><b> K.3.9.2.3.1 The wcstok_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
wchar_t *wcstok_s(wchar_t * restrict s1,
resumes on subsequent calls.
3 If there is a runtime-constraint violation, the wcstok_s function does not indirect
through the s1 or s2 pointers, and does not store a value in the object pointed to by ptr.
- Description
+<b> Description</b>
4 A sequence of calls to the wcstok_s function breaks the wide string pointed to by s1
into a sequence of tokens, each of which is delimited by a wide character from the wide
string pointed to by s2. The fourth argument points to a caller-provided wchar_t
and the wcstok_s function returns a null pointer. If such a wide character is found, it is
the start of the first token.
-
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+[<a name="p641" href="#p641">page 641</a>] (<a href="#Contents">Contents</a>)
7 The wcstok_s function then searches from there for the first wide character in s1 that
is contained in the current separator wide string. If no such wide character is found, the
to by ptr so that subsequent calls, with a null pointer for s1 and the unmodified pointer
value for ptr, shall start searching just past the element overwritten by a null wide
character (if any).
- Returns
+<b> Returns</b>
9 The wcstok_s function returns a pointer to the first wide character of a token, or a null
pointer if there is no token or there is a runtime-constraint violation.
10 EXAMPLE
<a name="K.3.9.2.4" href="#K.3.9.2.4"><b> K.3.9.2.4 Miscellaneous functions</b></a>
<a name="K.3.9.2.4.1" href="#K.3.9.2.4.1"><b> K.3.9.2.4.1 The wcsnlen_s function</b></a>
- Synopsis
+<b> Synopsis</b>
1 #define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
size_t wcsnlen_s(const wchar_t *s, size_t maxsize);
- Description
+<b> Description</b>
2 The wcsnlen_s function computes the length of the wide string pointed to by s.
- Returns
-3 If s is a null pointer,438) then the wcsnlen_s function returns zero.
+<b> Returns</b>
+3 If s is a null pointer,<sup><a href="#note438"><b>438)</b></a></sup> then the wcsnlen_s function returns zero.
4 Otherwise, the wcsnlen_s function returns the number of wide characters that precede
the terminating null wide character. If there is no null wide character in the first
maxsize wide characters of s then wcsnlen_s returns maxsize. At most the first
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#p642" href="p642">page 642</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p642" href="#p642">page 642</a>] (<a href="#Contents">Contents</a>)
maxsize wide characters of s shall be accessed by wcsnlen_s.
<a name="K.3.9.3" href="#K.3.9.3"><b> K.3.9.3 Extended multibyte/wide character conversion utilities</b></a>
1 Unlike wcrtomb, wcrtomb_s does not permit the ps parameter (the pointer to the
conversion state) to be a null pointer.
<a name="K.3.9.3.1.1" href="#K.3.9.3.1.1"><b> K.3.9.3.1.1 The wcrtomb_s function</b></a>
- Synopsis
+<b> Synopsis</b>
2 #include <a href="#7.28"><wchar.h></a>
errno_t wcrtomb_s(size_t * restrict retval,
char * restrict s, rsize_t smax,
not a null pointer and smax is greater than zero and not greater than RSIZE_MAX, then
wcrtomb_s sets s[0] to the null character. If retval is not a null pointer, then
wcrtomb_s sets *retval to (size_t)(-1).
- Description
+<b> Description</b>
5 If s is a null pointer, the wcrtomb_s function is equivalent to the call
wcrtomb_s(&retval, buf, sizeof buf, L'\0', ps)
where retval and buf are internal variables of the appropriate types, and the size of
sequence needed to restore the initial shift state; the resulting state described is the initial
conversion state.
- 438) Note that the wcsnlen_s function has no runtime-constraints. This lack of runtime-constraints
+ <sup><a name="note438" href="#note438"><b>438)</b></a></sup> Note that the wcsnlen_s function has no runtime-constraints. This lack of runtime-constraints
along with the values returned for a null pointer or an unterminated wide string argument make
wcsnlen_s useful in algorithms that gracefully handle such exceptional data.
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#p643" href="p643">page 643</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p643" href="#p643">page 643</a>] (<a href="#Contents">Contents</a>)
7 If wc does not correspond to a valid multibyte character, an encoding error occurs: the
wcrtomb_s function stores the value (size_t)(-1) into *retval and the
conversion state is unspecified. Otherwise, the wcrtomb_s function stores into
*retval the number of bytes (including any shift sequences) stored in the array pointed
to by s.
- Returns
+<b> Returns</b>
8 The wcrtomb_s function returns zero if no runtime-constraint violation and no
encoding error occurred. Otherwise, a nonzero value is returned.
<a name="K.3.9.3.2" href="#K.3.9.3.2"><b> K.3.9.3.2 Restartable multibyte/wide string conversion functions</b></a>
1 Unlike mbsrtowcs and wcsrtombs, mbsrtowcs_s and wcsrtombs_s do not
permit the ps parameter (the pointer to the conversion state) to be a null pointer.
<a name="K.3.9.3.2.1" href="#K.3.9.3.2.1"><b> K.3.9.3.2.1 The mbsrtowcs_s function</b></a>
- Synopsis
+<b> Synopsis</b>
2 #include <a href="#7.28"><wchar.h></a>
errno_t mbsrtowcs_s(size_t * restrict retval,
wchar_t * restrict dst, rsize_t dstmax,
retval is not a null pointer, then mbsrtowcs_s sets *retval to (size_t)(-1).
If dst is not a null pointer and dstmax is greater than zero and less than RSIZE_MAX,
then mbsrtowcs_s sets dst[0] to the null wide character.
- Description
+<b> Description</b>
5 The mbsrtowcs_s function converts a sequence of multibyte characters that begins in
the conversion state described by the object pointed to by ps, from the array indirectly
pointed to by src into a sequence of corresponding wide characters. If dst is not a null
continues up to and including a terminating null character, which is also stored.
Conversion stops earlier in two cases: when a sequence of bytes is encountered that does
not form a valid multibyte character, or (if dst is not a null pointer) when len wide
-[<a name="#p644" href="p644">page 644</a>] (<a href="#Contents">Contents</a>)
- characters have been stored into the array pointed to by dst.439) If dst is not a null
+[<a name="p644" href="#p644">page 644</a>] (<a href="#Contents">Contents</a>)
+
+ characters have been stored into the array pointed to by dst.<sup><a href="#note439"><b>439)</b></a></sup> If dst is not a null
pointer and no null wide character was stored into the array pointed to by dst, then
dst[len] is set to the null wide character. Each conversion takes place as if by a call
to the mbrtowc function.
terminating null character (if any).
8 All elements following the terminating null wide character (if any) written by
mbsrtowcs_s in the array of dstmax wide characters pointed to by dst take
- unspecified values when mbsrtowcs_s returns.440)
+ unspecified values when mbsrtowcs_s returns.<sup><a href="#note440"><b>440)</b></a></sup>
9 If copying takes place between objects that overlap, the objects take on unspecified
values.
- Returns
+<b> Returns</b>
10 The mbsrtowcs_s function returns zero if no runtime-constraint violation and no
encoding error occurred. Otherwise, a nonzero value is returned.
<a name="K.3.9.3.2.2" href="#K.3.9.3.2.2"><b> K.3.9.3.2.2 The wcsrtombs_s function</b></a>
- Synopsis
+<b> Synopsis</b>
11 #include <a href="#7.28"><wchar.h></a>
errno_t wcsrtombs_s(size_t * restrict retval,
char * restrict dst, rsize_t dstmax,
- 439) Thus, the value of len is ignored if dst is a null pointer.
- 440) This allows an implementation to attempt converting the multibyte string before discovering a
+ <sup><a name="note439" href="#note439"><b>439)</b></a></sup> Thus, the value of len is ignored if dst is a null pointer.
+ <sup><a name="note440" href="#note440"><b>440)</b></a></sup> This allows an implementation to attempt converting the multibyte string before discovering a
terminating null character did not occur where required.
-[<a name="
#p645" href="p645">page 645</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p645" href="#p645">page 645</a>] (<a href="#Contents">Contents</a>)
Runtime-constraints
12 None of retval, src, *src, or ps shall be null pointers. If dst is not a null pointer,
retval is not a null pointer, then wcsrtombs_s sets *retval to (size_t)(-1).
If dst is not a null pointer and dstmax is greater than zero and less than RSIZE_MAX,
then wcsrtombs_s sets dst[0] to the null character.
- Description
+<b> Description</b>
14 The wcsrtombs_s function converts a sequence of wide characters from the array
indirectly pointed to by src into a sequence of corresponding multibyte characters that
begins in the conversion state described by the object pointed to by ps. If dst is not a
If the conversion stops without converting a null wide character and dst is not a null
pointer, then a null character is stored into the array pointed to by dst immediately
following any multibyte characters already stored. Each conversion takes place as if by a
- call to the wcrtomb function.441)
+ call to the wcrtomb function.<sup><a href="#note441"><b>441)</b></a></sup>
15 If dst is not a null pointer, the pointer object pointed to by src is assigned either a null
pointer (if conversion stopped due to reaching a terminating null wide character) or the
address just past the last wide character converted (if any). If conversion stopped due to
conversion state.
- 441) If conversion stops because a terminating null wide character has been reached, the bytes stored
+ <sup><a name="note441" href="#note441"><b>441)</b></a></sup> If conversion stops because a terminating null wide character has been reached, the bytes stored
include those necessary to reach the initial shift state immediately before the null byte. However, if
the conversion stops before a terminating null wide character has been reached, the result will be null
terminated, but might not end in the initial shift state.
-[<a name="
#p646" href="p646">page 646</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p646" href="#p646">page 646</a>] (<a href="#Contents">Contents</a>)
16 Regardless of whether dst is or is not a null pointer, if the input conversion encounters a
wide character that does not correspond to a valid multibyte character, an encoding error
including the terminating null character (if any).
17 All elements following the terminating null character (if any) written by wcsrtombs_s
in the array of dstmax elements pointed to by dst take unspecified values when
- wcsrtombs_s returns.442)
+ wcsrtombs_s returns.<sup><a href="#note442"><b>442)</b></a></sup>
18 If copying takes place between objects that overlap, the objects take on unspecified
values.
- Returns
+<b> Returns</b>
19 The wcsrtombs_s function returns zero if no runtime-constraint violation and no
encoding error occurred. Otherwise, a nonzero value is returned.
- 442) When len is not less than dstmax, the implementation might fill the array before discovering a
+ <sup><a name="note442" href="#note442"><b>442)</b></a></sup> When len is not less than dstmax, the implementation might fill the array before discovering a
runtime-constraint violation.
-[<a name="
#p647" href="p647">page 647</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p647" href="#p647">page 647</a>] (<a href="#Contents">Contents</a>)
<a name="L" href="#L"><b> Annex L</b></a>
(normative)
<a name="L.1" href="#L.1"><b> L.1 Scope</b></a>
1 This annex specifies optional behavior that can aid in the analyzability of C programs.
2 An implementation that defines __STDC_ANALYZABLE__ shall conform to the
- specifications in this annex.443)
+ specifications in this annex.<sup><a href="#note443"><b>443)</b></a></sup>
<a name="L.2" href="#L.2"><b> L.2 Definitions</b></a>
<a name="L.2.1" href="#L.2.1"><b> L.2.1</b></a>
1 out-of-bounds store
- 443) Implementations that do not define __STDC_ANALYZABLE__ are not required to conform to these
+ <sup><a name="note443" href="#note443"><b>443)</b></a></sup> Implementations that do not define __STDC_ANALYZABLE__ are not required to conform to these
specifications.
-[<a name="
#p648" href="p648">page 648</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p648" href="#p648">page 648</a>] (<a href="#Contents">Contents</a>)
<a name="L.3" href="#L.3"><b> L.3 Requirements</b></a>
1 If the program performs a trap (<a href="#3.19.5">3.19.5</a>), the implementation is permitted to invoke a
-- A string or wide string utility function is instructed to access an array beyond the end
of an object (<a href="#7.23.1">7.23.1</a>, <a href="#7.28.4">7.28.4</a>).
-
-
-
-[<a name="#p649" href="p649">page 649</a>] (<a href="#Contents">Contents</a>)
+[<a name="p649" href="#p649">page 649</a>] (<a href="#Contents">Contents</a>)
<a name="Bibliography" href="#Bibliography"><b> Bibliography</b></a>
18. ISO/IEC 9899:1999/Cor.2:2004, Technical Corrigendum 2.
19. ISO/IEC 9899:1999/Cor.3:2007, Technical Corrigendum 3.
-
-
-[<a name="#p650" href="p650">page 650</a>] (<a href="#Contents">Contents</a>)
+[<a name="p650" href="#p650">page 650</a>] (<a href="#Contents">Contents</a>)
20. ISO/IEC 9945-2:1993, Information technology -- Portable Operating System
Interface (POSIX) -- Part 2: Shell and Utilities.
37. ISO/IEC 10967-1:1994, Information technology -- Language independent
arithmetic -- Part 1: Integer and floating point arithmetic.
-
-[<a name="#p651" href="p651">page 651</a>] (<a href="#Contents">Contents</a>)
+[<a name="p651" href="#p651">page 651</a>] (<a href="#Contents">Contents</a>)
38. ISO/IEC TR 19769:2004, Information technology -- Programming languages,
their environments and system software interfaces -- Extensions for the
their environments and system software interfaces -- Extensions to the C library
-- Part 1: Bounds-checking interfaces.
-
-
-
-[<a name="#p652" href="p652">page 652</a>] (<a href="#Contents">Contents</a>)
+[<a name="p652" href="#p652">page 652</a>] (<a href="#Contents">Contents</a>)
<a name="Index" href="#Index"><b>Index</b></a>
++ (postfix increment operator), <a href="#6.3.2.1">6.3.2.1</a>, <a href="#6.5.2.4">6.5.2.4</a> <a href="#7.18"><stdbool.h></a> header, <a href="#4">4</a>, <a href="#7.18">7.18</a>, <a href="#7.30.7">7.30.7</a>, <a href="#H">H</a>
++ (prefix increment operator), <a href="#6.3.2.1">6.3.2.1</a>, <a href="#6.5.3.1">6.5.3.1</a> <a href="#7.19"><stddef.h></a> header, <a href="#4">4</a>, <a href="#6.3.2.1">6.3.2.1</a>, <a href="#6.3.2.3">6.3.2.3</a>, <a href="#6.4.4.4">6.4.4.4</a>,
+= (addition assignment operator), <a href="#6.5.16.2">6.5.16.2</a>
-[<a name="#p653" href="p653">page 653</a>] (<a href="#Contents">Contents</a>)
+
+[<a name="p653" href="#p653">page 653</a>] (<a href="#Contents">Contents</a>)
<a href="#6.4.5">6.4.5</a>, <a href="#6.5.3.4">6.5.3.4</a>, <a href="#6.5.6">6.5.6</a>, <a href="#7.19">7.19</a>, <a href="#K.3.3">K.3.3</a> \x hexadecimal digits (hexadecimal-character
<a href="#7.20"><stdint.h></a> header, <a href="#4">4</a>, <a href="#5.2.4.2">5.2.4.2</a>, <a href="#6.10.1">6.10.1</a>, <a href="#7.8">7.8</a>, escape sequence), <a href="#6.4.4.4">6.4.4.4</a>
\v (vertical-tab escape sequence), <a href="#5.2.2">5.2.2</a>, <a href="#6.4.4.4">6.4.4.4</a>, _Noreturn, <a href="#6.7.4">6.7.4</a>
<a href="#7.4.1.10">7.4.1.10</a> _Pragma operator, <a href="#5.1.1.2">5.1.1.2</a>, <a href="#6.10.9">6.10.9</a>
-[<a name="
#p654" href="p654">page 654</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p654" href="#p654">page 654</a>] (<a href="#Contents">Contents</a>)
_Static_assert, <a href="#6.7.10">6.7.10</a>, <a href="#7.2">7.2</a> allocated storage, order and contiguity, <a href="#7.22.3">7.22.3</a>
_Thread_local storage-class specifier, <a href="#6.2.4">6.2.4</a>, and macro, <a href="#7.9">7.9</a>
alignment specifier, <a href="#6.7.5">6.7.5</a> asin type-generic macro, <a href="#7.24">7.24</a>, <a href="#G.7">G.7</a>
alignof operator, <a href="#6.5.3">6.5.3</a>, <a href="#6.5.3.4">6.5.3.4</a> asinh functions, <a href="#7.12.5.2">7.12.5.2</a>, <a href="#F.10.2.2">F.10.2.2</a>
-[<a name="
#p655" href="p655">page 655</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p655" href="#p655">page 655</a>] (<a href="#Contents">Contents</a>)
asinh type-generic macro, <a href="#7.24">7.24</a>, <a href="#G.7">G.7</a> atomic_is_lock_free generic function,
asm keyword, <a href="#J.5.10">J.5.10</a> <a href="#7.17.5.1">7.17.5.1</a>
atomic_init generic function, <a href="#7.17.2.2">7.17.2.2</a> brackets operator ([ ]), <a href="#6.5.2.1">6.5.2.1</a>, <a href="#6.5.3.2">6.5.3.2</a>
ATOMIC_INT_LOCK_FREE macro, <a href="#7.17.1">7.17.1</a> brackets punctuator ([ ]), <a href="#6.7.6.2">6.7.6.2</a>, <a href="#6.7.9">6.7.9</a>
-[<a name="
#p656" href="p656">page 656</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p656" href="#p656">page 656</a>] (<a href="#Contents">Contents</a>)
branch cuts, <a href="#7.3.3">7.3.3</a> type-generic macro for, <a href="#7.24">7.24</a>
break statement, <a href="#6.8.6.3">6.8.6.3</a> ccosh functions, <a href="#7.3.6.4">7.3.6.4</a>, <a href="#G.6.2.4">G.6.2.4</a>
cbrt type-generic macro, <a href="#7.24">7.24</a> CLOCKS_PER_SEC macro, <a href="#7.26.1">7.26.1</a>, <a href="#7.26.2.1">7.26.2.1</a>
ccos functions, <a href="#7.3.5.4">7.3.5.4</a>, <a href="#G.6">G.6</a> clog functions, <a href="#7.3.7.2">7.3.7.2</a>, <a href="#G.6.3.2">G.6.3.2</a>
-[<a name="
#p657" href="p657">page 657</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p657" href="#p657">page 657</a>] (<a href="#Contents">Contents</a>)
type-generic macro for, <a href="#7.24">7.24</a> string, <a href="#7.23.3">7.23.3</a>, <a href="#K.3.7.2">K.3.7.2</a>
clog10 function, <a href="#7.30.1">7.30.1</a> wide string, <a href="#7.28.4.3">7.28.4.3</a>, <a href="#K.3.9.2.2">K.3.9.2.2</a>
compound-literal operator (( ){ }), <a href="#6.5.2.5">6.5.2.5</a> imaginary and complex, <a href="#G.4.3">G.4.3</a>
concatenation functions implicit, <a href="#6.3">6.3</a>
-[<a name="
#p658" href="p658">page 658</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p658" href="#p658">page 658</a>] (<a href="#Contents">Contents</a>)
lvalues, <a href="#6.3.2.1">6.3.2.1</a> csinh functions, <a href="#7.3.6.5">7.3.6.5</a>, <a href="#G.6.2.5">G.6.2.5</a>
pointer, <a href="#6.3.2.1">6.3.2.1</a>, <a href="#6.3.2.3">6.3.2.3</a> type-generic macro for, <a href="#7.24">7.24</a>
csin functions, <a href="#7.3.5.5">7.3.5.5</a>, <a href="#G.6">G.6</a> default argument promotions, <a href="#6.5.2.2">6.5.2.2</a>
type-generic macro for, <a href="#7.24">7.24</a> default initialization, <a href="#6.7.9">6.7.9</a>
-[<a name="
#p659" href="p659">page 659</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p659" href="#p659">page 659</a>] (<a href="#Contents">Contents</a>)
default label, <a href="#6.8.1">6.8.1</a>, <a href="#6.8.4.2">6.8.4.2</a> elif preprocessing directive, <a href="#6.10.1">6.10.1</a>
define preprocessing directive, <a href="#6.10.3">6.10.3</a> ellipsis punctuator (...), <a href="#6.5.2.2">6.5.2.2</a>, <a href="#6.7.6.3">6.7.6.3</a>, <a href="#6.10.3">6.10.3</a>
see also encoding error <a href="#7.22.1.3">7.22.1.3</a>, <a href="#7.22.1.4">7.22.1.4</a>, <a href="#7.28.4.1.1">7.28.4.1.1</a>, <a href="#7.28.4.1.2">7.28.4.1.2</a>, see
element type, <a href="#6.2.5">6.2.5</a> also range error, pole error
-[<a name="
#p660" href="p660">page 660</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p660" href="#p660">page 660</a>] (<a href="#Contents">Contents</a>)
erf functions, <a href="#7.12.8.1">7.12.8.1</a>, <a href="#F.10.5.1">F.10.5.1</a> exp2 functions, <a href="#7.12.6.2">7.12.6.2</a>, <a href="#F.10.3.2">F.10.3.2</a>
erf type-generic macro, <a href="#7.24">7.24</a> exp2 type-generic macro, <a href="#7.24">7.24</a>
exp functions, <a href="#7.12.6.1">7.12.6.1</a>, <a href="#F.10.3.1">F.10.3.1</a> FE_INVALID macro, <a href="#7.6">7.6</a>, <a href="#7.12">7.12</a>, <a href="#F.3">F.3</a>
exp type-generic macro, <a href="#7.24">7.24</a> FE_OVERFLOW macro, <a href="#7.6">7.6</a>, <a href="#7.12">7.12</a>, <a href="#F.3">F.3</a>
-[<a name="
#p661" href="p661">page 661</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p661" href="#p661">page 661</a>] (<a href="#Contents">Contents</a>)
FE_TONEAREST macro, <a href="#7.6">7.6</a>, <a href="#F.3">F.3</a> float _Complex type conversion, <a href="#6.3.1.6">6.3.1.6</a>,
FE_TOWARDZERO macro, <a href="#7.6">7.6</a>, <a href="#F.3">F.3</a> <a href="#6.3.1.7">6.3.1.7</a>, <a href="#6.3.1.8">6.3.1.8</a>
flexible array member, <a href="#6.7.2.1">6.7.2.1</a> fmod functions, <a href="#7.12.10.1">7.12.10.1</a>, <a href="#F.10.7.1">F.10.7.1</a>
float _Complex type, <a href="#6.2.5">6.2.5</a> fmod type-generic macro, <a href="#7.24">7.24</a>
-[<a name="
#p662" href="p662">page 662</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p662" href="#p662">page 662</a>] (<a href="#Contents">Contents</a>)
fopen function, <a href="#7.21.5.3">7.21.5.3</a>, <a href="#7.21.5.4">7.21.5.4</a>, <a href="#K.3.5.2.1">K.3.5.2.1</a> <a href="#K.3.5.3.7">K.3.5.3.7</a>, <a href="#K.3.5.3.9">K.3.5.3.9</a>
FOPEN_MAX macro, <a href="#7.21.1">7.21.1</a>, <a href="#7.21.3">7.21.3</a>, <a href="#7.21.4.3">7.21.4.3</a>, fseek function, <a href="#7.21.1">7.21.1</a>, <a href="#7.21.5.3">7.21.5.3</a>, <a href="#7.21.7.10">7.21.7.10</a>,
<a href="#7.21.6.4">7.21.6.4</a>, <a href="#7.21.6.7">7.21.6.7</a>, <a href="#7.21.6.9">7.21.6.9</a>, <a href="#F.3">F.3</a>, <a href="#K.3.5.3.2">K.3.5.3.2</a> <a href="#K.3.9.1.7">K.3.9.1.7</a>, <a href="#K.3.9.1.14">K.3.9.1.14</a>
fscanf_s function, <a href="#K.3.5.3.2">K.3.5.3.2</a>, <a href="#K.3.5.3.4">K.3.5.3.4</a>,
-[<a name="
#p663" href="p663">page 663</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p663" href="#p663">page 663</a>] (<a href="#Contents">Contents</a>)
gamma functions, <a href="#7.12.8">7.12.8</a>, <a href="#F.10.5">F.10.5</a> name spaces, <a href="#6.2.3">6.2.3</a>
general utilities, <a href="#7.22">7.22</a>, <a href="#K.3.6">K.3.6</a> reserved, <a href="#6.4.1">6.4.1</a>, <a href="#7.1.3">7.1.3</a>, <a href="#K.3.1.2">K.3.1.2</a>
linkage, see linkage indirection operator (*), <a href="#6.5.2.1">6.5.2.1</a>, <a href="#6.5.3.2">6.5.3.2</a>
maximum length, <a href="#6.4.2.1">6.4.2.1</a> inequality operator (!=), <a href="#6.5.9">6.5.9</a>
-[<a name="
#p664" href="p664">page 664</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p664" href="#p664">page 664</a>] (<a href="#Contents">Contents</a>)
infinitary, <a href="#7.12.1">7.12.1</a> extended, <a href="#6.2.5">6.2.5</a>, <a href="#6.3.1.1">6.3.1.1</a>, <a href="#6.4.4.1">6.4.4.1</a>, <a href="#7.20">7.20</a>
INFINITY macro, <a href="#7.3.9.5">7.3.9.5</a>, <a href="#7.12">7.12</a>, <a href="#F.2.1">F.2.1</a> inter-thread happens before, <a href="#5.1.2.4">5.1.2.4</a>
<a href="#F.3">F.3</a>, <a href="#F.4">F.4</a> <a href="#7.4.1.11">7.4.1.11</a>
integer types, <a href="#6.2.5">6.2.5</a>, <a href="#7.20">7.20</a> isspace function, <a href="#7.4.1.2">7.4.1.2</a>, <a href="#7.4.1.7">7.4.1.7</a>, <a href="#7.4.1.9">7.4.1.9</a>,
-[<a name="
#p665" href="p665">page 665</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p665" href="#p665">page 665</a>] (<a href="#Contents">Contents</a>)
<a href="#7.4.1.10">7.4.1.10</a>, <a href="#7.4.1.11">7.4.1.11</a>, <a href="#7.21.6.2">7.21.6.2</a>, <a href="#7.22.1.3">7.22.1.3</a>, LC_ALL macro, <a href="#7.11">7.11</a>, <a href="#7.11.1.1">7.11.1.1</a>, <a href="#7.11.2.1">7.11.2.1</a>
<a href="#7.22.1.4">7.22.1.4</a>, <a href="#7.28.2.2">7.28.2.2</a> LC_COLLATE macro, <a href="#7.11">7.11</a>, <a href="#7.11.1.1">7.11.1.1</a>, <a href="#7.23.4.3">7.23.4.3</a>,
syntax summary, <a href="#A">A</a> lifetime, <a href="#6.2.4">6.2.4</a>
Latin alphabet, <a href="#5.2.1">5.2.1</a>, <a href="#6.4.2.1">6.4.2.1</a> limits
-[<a name="
#p666" href="p666">page 666</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p666" href="#p666">page 666</a>] (<a href="#Contents">Contents</a>)
environmental, see environmental limits <a href="#6.3.1.6">6.3.1.6</a>, <a href="#6.3.1.7">6.3.1.7</a>, <a href="#6.3.1.8">6.3.1.8</a>
implementation, see implementation limits long double _Imaginary type, <a href="#G.2">G.2</a>
long double _Complex type, <a href="#6.2.5">6.2.5</a> manipulation functions
long double _Complex type conversion, complex, <a href="#7.3.9">7.3.9</a>
-[<a name="
#p667" href="p667">page 667</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p667" href="#p667">page 667</a>] (<a href="#Contents">Contents</a>)
real, <a href="#7.12.11">7.12.11</a>, <a href="#F.10.8">F.10.8</a> modf functions, <a href="#7.12.6.12">7.12.6.12</a>, <a href="#F.10.3.12">F.10.3.12</a>
matching failure, <a href="#7.28.2.6">7.28.2.6</a>, <a href="#7.28.2.8">7.28.2.8</a>, <a href="#7.28.2.10">7.28.2.10</a>, modifiable lvalue, <a href="#6.3.2.1">6.3.2.1</a>
wide string, <a href="#7.28.4.6">7.28.4.6</a>, <a href="#K.3.9.2.4">K.3.9.2.4</a> <a href="#F.10.6.3">F.10.6.3</a>
mktime function, <a href="#7.26.2.3">7.26.2.3</a> nearbyint type-generic macro, <a href="#7.24">7.24</a>
-[<a name="
#p668" href="p668">page 668</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p668" href="#p668">page 668</a>] (<a href="#Contents">Contents</a>)
nearest integer functions, <a href="#7.12.9">7.12.9</a>, <a href="#F.10.6">F.10.6</a> operating system, <a href="#5.1.2.1">5.1.2.1</a>, <a href="#7.22.4.8">7.22.4.8</a>
negation operator (!), <a href="#6.5.3.3">6.5.3.3</a> operations on files, <a href="#7.21.4">7.21.4</a>, <a href="#K.3.5.1">K.3.5.1</a>
ones' complement, <a href="#6.2.6.2">6.2.6.2</a> parenthesized expression, <a href="#6.5.1">6.5.1</a>
operand, <a href="#6.4.6">6.4.6</a>, <a href="#6.5">6.5</a> parse state, <a href="#7.21.2">7.21.2</a>
-[<a name="
#p669" href="p669">page 669</a>] (<a href="#Contents">Contents</a>)
+[<a name="
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perform a trap, <a href="#3.19.5">3.19.5</a> preprocessor, <a href="#6.10">6.10</a>
permitted form of initializer, <a href="#6.6">6.6</a> PRIcFASTN macros, <a href="#7.8.1">7.8.1</a>
preprocessing tokens, <a href="#5.1.1.2">5.1.1.2</a>, <a href="#6.4">6.4</a>, <a href="#6.10">6.10</a> raise function, <a href="#7.14">7.14</a>, <a href="#7.14.1.1">7.14.1.1</a>, <a href="#7.14.2.1">7.14.2.1</a>, <a href="#7.22.4.1">7.22.4.1</a>
preprocessing translation unit, <a href="#5.1.1.1">5.1.1.1</a> rand function, <a href="#7.22">7.22</a>, <a href="#7.22.2.1">7.22.2.1</a>, <a href="#7.22.2.2">7.22.2.2</a>
-[<a name="
#p670" href="p670">page 670</a>] (<a href="#Contents">Contents</a>)
+[<a name="
p670" href="#p670">page 670</a>] (<a href="#Contents">Contents</a>)
RAND_MAX macro, <a href="#7.22">7.22</a>, <a href="#7.22.2.1">7.22.2.1</a> restrict-qualified type, <a href="#6.2.5">6.2.5</a>, <a href="#6.7.3">6.7.3</a>
range return statement, <a href="#6.8.6.4">6.8.6.4</a>, <a href="#F.6">F.6</a>
restore calling environment function, <a href="#7.13.2">7.13.2</a> utility, <a href="#7.22.5">7.22.5</a>, <a href="#K.3.6.3">K.3.6.3</a>
restrict type qualifier, <a href="#6.7.3">6.7.3</a>, <a href="#6.7.3.1">6.7.3.1</a> wide string, <a href="#7.28.4.5">7.28.4.5</a>, <a href="#K.3.9.2.3">K.3.9.2.3</a>
-[<a name="
#p671" href="p671">page 671</a>] (<a href="#Contents">Contents</a>)
+[<a name="
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SEEK_CUR macro, <a href="#7.21.1">7.21.1</a>, <a href="#7.21.9.2">7.21.9.2</a> sign and magnitude, <a href="#6.2.6.2">6.2.6.2</a>
SEEK_END macro, <a href="#7.21.1">7.21.1</a>, <a href="#7.21.9.2">7.21.9.2</a> sign bit, <a href="#6.2.6.2">6.2.6.2</a>
SIGILL macro, <a href="#7.14">7.14</a>, <a href="#7.14.1.1">7.14.1.1</a> sprintf function, <a href="#7.21.6.6">7.21.6.6</a>, <a href="#7.21.6.13">7.21.6.13</a>, <a href="#K.3.5.3.6">K.3.5.3.6</a>
SIGINT macro, <a href="#7.14">7.14</a> sprintf_s function, <a href="#K.3.5.3.5">K.3.5.3.5</a>, <a href="#K.3.5.3.6">K.3.5.3.6</a>
-[<a name="
#p672" href="p672">page 672</a>] (<a href="#Contents">Contents</a>)
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sqrt functions, <a href="#7.12.7.5">7.12.7.5</a>, <a href="#F.3">F.3</a>, <a href="#F.10.4.5">F.10.4.5</a> do, <a href="#6.8.5.2">6.8.5.2</a>
sqrt type-generic macro, <a href="#7.24">7.24</a> else, <a href="#6.8.4.1">6.8.4.1</a>
compound, <a href="#6.8.2">6.8.2</a> strcpy_s function, <a href="#K.3.7.1.3">K.3.7.1.3</a>
continue, <a href="#6.8.6.2">6.8.6.2</a> strcspn function, <a href="#7.23.5.3">7.23.5.3</a>
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#p673" href="p673">page 673</a>] (<a href="#Contents">Contents</a>)
+[<a name="
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streams, <a href="#7.21.2">7.21.2</a>, <a href="#7.22.4.4">7.22.4.4</a> <a href="#7.22.1.4">7.22.1.4</a>, <a href="#7.28.2.2">7.28.2.2</a>
fully buffered, <a href="#7.21.3">7.21.3</a> strtoull function, <a href="#7.8.2.3">7.8.2.3</a>, <a href="#7.22.1.2">7.22.1.2</a>, <a href="#7.22.1.4">7.22.1.4</a>
strtoll function, <a href="#7.8.2.3">7.8.2.3</a>, <a href="#7.22.1.2">7.22.1.2</a>, <a href="#7.22.1.4">7.22.1.4</a> tan type-generic macro, <a href="#7.24">7.24</a>, <a href="#G.7">G.7</a>
strtoul function, <a href="#7.8.2.3">7.8.2.3</a>, <a href="#7.21.6.2">7.21.6.2</a>, <a href="#7.22.1.2">7.22.1.2</a>, tanh functions, <a href="#7.12.5.6">7.12.5.6</a>, <a href="#F.10.2.6">F.10.2.6</a>
-[<a name="
#p674" href="p674">page 674</a>] (<a href="#Contents">Contents</a>)
+[<a name="
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tanh type-generic macro, <a href="#7.24">7.24</a>, <a href="#G.7">G.7</a> toupper function, <a href="#7.4.2.2">7.4.2.2</a>
temporary lifetime, <a href="#6.2.4">6.2.4</a> towctrans function, <a href="#7.29.3.2.1">7.29.3.2.1</a>, <a href="#7.29.3.2.2">7.29.3.2.2</a>
token pasting, <a href="#6.10.3.3">6.10.3.3</a> restrict qualified, <a href="#6.7.3">6.7.3</a>
tolower function, <a href="#7.4.2.1">7.4.2.1</a> volatile qualified, <a href="#6.7.3">6.7.3</a>
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#p675" href="p675">page 675</a>] (<a href="#Contents">Contents</a>)
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uchar.h header, <a href="#6.4.4.4">6.4.4.4</a>, <a href="#6.4.5">6.4.5</a>, <a href="#7.27">7.27</a> universal character name, <a href="#6.4.3">6.4.3</a>
UCHAR_MAX macro, <a href="#5.2.4.2.1">5.2.4.2.1</a> unnormalized floating-point numbers, <a href="#5.2.4.2.2">5.2.4.2.2</a>
tag, <a href="#6.2.3">6.2.3</a>, <a href="#6.7.2.3">6.7.2.3</a> value, <a href="#3.19">3.19</a>
type, <a href="#6.2.5">6.2.5</a>, <a href="#6.7.2.1">6.7.2.1</a> value bits, <a href="#6.2.6.2">6.2.6.2</a>
-[<a name="
#p676" href="p676">page 676</a>] (<a href="#Contents">Contents</a>)
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variable arguments, <a href="#6.10.3">6.10.3</a>, <a href="#7.16">7.16</a> vswscanf function, <a href="#7.28.2.8">7.28.2.8</a>
variable arguments header, <a href="#7.16">7.16</a> vswscanf_s function, <a href="#K.3.9.1.10">K.3.9.1.10</a>
<a href="#K.3.9.1.9">K.3.9.1.9</a> wcstold function, <a href="#7.28.4.1.1">7.28.4.1.1</a>
vswprintf_s function, <a href="#K.3.9.1.8">K.3.9.1.8</a>, <a href="#K.3.9.1.9">K.3.9.1.9</a> wcstoll function, <a href="#7.8.2.4">7.8.2.4</a>, <a href="#7.28.4.1.2">7.28.4.1.2</a>
-[<a name="
#p677" href="p677">page 677</a>] (<a href="#Contents">Contents</a>)
+[<a name="
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wcstombs function, <a href="#7.22.8.2">7.22.8.2</a>, <a href="#7.28.6.4">7.28.6.4</a> <a href="#7.29.1">7.29.1</a>
wcstombs_s function, <a href="#K.3.6.5.2">K.3.6.5.2</a> wmemchr function, <a href="#7.28.4.5.8">7.28.4.5.8</a>
WINT_MIN macro, <a href="#7.20.3">7.20.3</a>
wint_t type, <a href="#7.20.3">7.20.3</a>, <a href="#7.21.6.1">7.21.6.1</a>, <a href="#7.28.1">7.28.1</a>, <a href="#7.28.2.1">7.28.2.1</a>,
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</pre></body></html>
projects / c-standard / blobdiff