char a;
int b:5, c:11, :0, d:8;
struct { int ee:8; } e;
- }</pre>
+ }
+</pre>
contains four separate memory locations: The member a, and bit-fields d and e.ee are each separate
memory locations, and can be modified concurrently without interfering with each other. The bit-fields b
and c together constitute the fourth memory location. The bit-fields b and c cannot be concurrently
/* ... */
fesetround(FE_UPWARD);
/* ... */
- #endif</pre>
+ #endif
+</pre>
</small>
<p><small><a name="note4" href="#note4">4)</a> This implies that a conforming implementation reserves no identifiers other than those explicitly
EXAMPLE An implementation shall issue a diagnostic for the translation unit:
<pre>
char i;
- int i;</pre>
+ int i;
+</pre>
because in those cases where wording in this International Standard describes the behavior for a construct
as being both a constraint error and resulting in undefined behavior, the constraint error shall be diagnosed.
prototype for this function. It shall be defined with a return type of int and with no
parameters:
<pre>
- int main(void) { /* ... */ }</pre>
+ int main(void) { /* ... */ }
+</pre>
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):
<pre>
- int main(int argc, char *argv[]) { /* ... */ }</pre>
+ int main(int argc, char *argv[]) { /* ... */ }
+</pre>
or equivalent;<sup><a href="#note10"><b>10)</b></a></sup> or in some other implementation-defined manner.
<p><!--para 2 -->
If they are declared, the parameters to the main function shall obey the following
<pre>
char c1, c2;
/* ... */
- c1 = c1 + c2;</pre>
+ c1 = c1 + c2;
+</pre>
the ''integer promotions'' require that the abstract machine promote the value of each variable to int size
and then add the two ints and truncate the sum. Provided the addition of two chars can be done without
overflow, or with overflow wrapping silently to produce the correct result, the actual execution need only
float f1, f2;
double d;
/* ... */
- f1 = f2 * d;</pre>
+ f1 = f2 * d;
+</pre>
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 2.0, which has type double).
double d1, d2;
float f;
d1 = f = expression;
- d2 = (float) expression;</pre>
+ d2 = (float) expression;
+</pre>
the values assigned to d1 and d2 are required to have been converted to float.
<p><!--para 14 -->
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 * (1.0 + y);
- y = x / 5.0; // not equivalent to y = x * 0.2;</pre>
+ y = x / 5.0; // not equivalent to y = x * 0.2;
+</pre>
<p><!--para 15 -->
EXAMPLE 6 To illustrate the grouping behavior of expressions, in the following fragment
<pre>
int a, b;
/* ... */
- a = a + 32760 + b + 5;</pre>
+ a = a + 32760 + b + 5;
+</pre>
the expression statement behaves exactly the same as
<pre>
- a = (((a + 32760) + b) + 5);</pre>
+ a = (((a + 32760) + b) + 5);
+</pre>
due to the associativity and precedence of these operators. Thus, the result of the sum (a + 32760) is
next added to b, and that result is then added to 5 which results in the value assigned to a. On a machine in
which overflows produce an explicit trap and in which the range of values representable by an int is
[-32768, +32767], the implementation cannot rewrite this expression as
<pre>
- a = ((a + b) + 32765);</pre>
+ a = ((a + b) + 32765);
+</pre>
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
<!--page 35 -->
<pre>
- a = ((a + 32765) + b);</pre>
+ a = ((a + 32765) + b);
+</pre>
or
<pre>
- a = (a + (b + 32765));</pre>
+ a = (a + (b + 32765));
+</pre>
since the values for a and b might have been, respectively, 4 and -8 or -17 and 12. However, on a machine
in which overflow silently generates some value and where positive and negative overflows cancel, the
above expression statement can be rewritten by the implementation in any of the above ways because the
int sum;
char *p;
/* ... */
- sum = sum * 10 - '0' + (*p++ = getchar());</pre>
+ sum = sum * 10 - '0' + (*p++ = getchar());
+</pre>
the expression statement is grouped as if it were written as
<pre>
- sum = (((sum * 10) - '0') + ((*(p++)) = (getchar())));</pre>
+ sum = (((sum * 10) - '0') + ((*(p++)) = (getchar())));
+</pre>
but the actual increment of p can occur at any time between the previous sequence point and the next
sequence point (the ;), and the call to getchar can occur at any point prior to the need of its returned
value.
members: the 26 uppercase letters of the Latin alphabet
<pre>
A B C D E F G H I J K L M
- N O P Q R S T U V W X Y Z</pre>
+ N O P Q R S T U V W X Y Z
+</pre>
the 26 lowercase letters of the Latin alphabet
<pre>
a b c d e f g h i j k l m
- n o p q r s t u v w x y z</pre>
+ n o p q r s t u v w x y z
+</pre>
the 10 decimal digits
<pre>
- 0 1 2 3 4 5 6 7 8 9</pre>
+ 0 1 2 3 4 5 6 7 8 9
+</pre>
the following 29 graphic characters
<pre>
! " # % & ' ( ) * + , - . / :
- ; < = > ? [ \ ] ^ _ { | } ~</pre>
+ ; < = > ? [ \ ] ^ _ { | } ~
+</pre>
the space character, and control characters representing horizontal tab, vertical tab, and
form feed. The representation of each member of the source and execution basic
character sets shall fit in a byte. In both the source and execution basic character sets, the
<pre>
??= # ??) ] ??! |
??( [ ??' ^ ??> }
- ??/ \ ??< { ??- ~</pre>
+ ??/ \ ??< { ??- ~
+</pre>
No other trigraph sequences exist. Each ? that does not begin one of the trigraphs listed
above is not changed.
<p><!--para 2 -->
EXAMPLE 1
<pre>
- ??=define arraycheck(a, b) a??(b??) ??!??! b??(a??)</pre>
+ ??=define arraycheck(a, b) a??(b??) ??!??! b??(a??)
+</pre>
becomes
<pre>
- #define arraycheck(a, b) a[b] || b[a]</pre>
+ #define arraycheck(a, b) a[b] || b[a]
+</pre>
<p><!--para 3 -->
EXAMPLE 2 The following source line
<pre>
- printf("Eh???/n");</pre>
+ printf("Eh???/n");
+</pre>
becomes (after replacement of the trigraph sequence ??/)
<pre>
- printf("Eh?\n");</pre>
+ printf("Eh?\n");
+</pre>
<h6>footnotes</h6>
\b (backspace) Moves the active position to the previous position on the current line. If
<pre>
the active position is at the initial position of a line, the behavior of the display
- device is unspecified.</pre>
+ device is unspecified.
+</pre>
\f ( form feed) Moves the active position to the initial position at the start of the next
<pre>
- logical page.</pre>
+ logical page.
+</pre>
\n (new line) Moves the active position to the initial position of the next line.
\r (carriage return) Moves the active position to the initial position of the current line.
\t (horizontal tab) Moves the active position to the next horizontal tabulation position
<pre>
on the current line. If the active position is at or past the last defined horizontal
- tabulation position, the behavior of the display device is unspecified.</pre>
+ tabulation position, the behavior of the display device is unspecified.
+</pre>
\v (vertical tab) Moves the active position to the initial position of the next vertical
<!--page 43 -->
<pre>
tabulation position. If the active position is at or past the last defined vertical
- tabulation position, the behavior of the display device is unspecified.</pre>
+ tabulation position, the behavior of the display device is unspecified.
+</pre>
<p><!--para 3 -->
Each of these escape sequences shall produce a unique implementation-defined value
which can be stored in a single char object. The external representations in a text file
<pre>
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)<sup><a href="#note19"><b>19)</b></a></sup></pre>
+ number of characters as the corresponding universal character name, if any)<sup><a href="#note19"><b>19)</b></a></sup>
+</pre>
<li> 4095 external identifiers in one translation unit
<li> 511 identifiers with block scope declared in one block
<li> 4095 macro identifiers simultaneously defined in one preprocessing translation unit
b base or radix of exponent representation (an integer > 1)
e exponent (an integer between a minimum emin and a maximum emax )
p precision (the number of base-b digits in the significand)
- fk nonnegative integers less than b (the significand digits)</pre>
+ fk nonnegative integers less than b (the significand digits)
+</pre>
<p><!--para 2 -->
A floating-point number (x) is defined by the following model:
<pre>
p
x = sb e (Sum) f k b-k ,
k=1
- emin <= e <= emax</pre>
+ emin <= e <= emax
+</pre>
<p><!--para 3 -->
In addition to normalized floating-point numbers ( f 1 > 0 if x != 0), floating types may be
0 toward zero
1 to nearest
2 toward positive infinity
- 3 toward negative infinity</pre>
+ 3 toward negative infinity
+</pre>
All other values for FLT_ROUNDS characterize implementation-defined rounding
behavior.
operations and constants to the range and precision of the long double
type;
2 evaluate all operations and constants to the range and precision of the
- long double type.</pre>
+ long double type.
+</pre>
All other negative values for FLT_EVAL_METHOD characterize implementation-defined
behavior.
<p><!--para 10 -->
<pre>
-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)</pre>
+ 1 present (type does support subnormal numbers)
+</pre>
<p><!--para 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
<pre>
{ p log10 b if b is a power of 10
{
- { [^1 + p log10 b^] otherwise</pre>
+ { [^1 + p log10 b^] otherwise
+</pre>
FLT_DECIMAL_DIG 6
DBL_DECIMAL_DIG 10
LDBL_DECIMAL_DIG 10
<pre>
{ pmax log10 b if b is a power of 10
{
- { [^1 + pmax log10 b^] otherwise</pre>
+ { [^1 + pmax log10 b^] otherwise
+</pre>
DECIMAL_DIG 10
<li> number of decimal digits, q, such that any floating-point number with q decimal digits
can be rounded into a floating-point number with p radix b digits and back again
<pre>
{ p log10 b if b is a power of 10
{
- { [_( p - 1) log10 b_] otherwise</pre>
+ { [_( p - 1) log10 b_] otherwise
+</pre>
FLT_DIG 6
DBL_DIG 10
LDBL_DIG 10
<li> minimum negative integer such that 10 raised to that power is in the range of
normalized floating-point numbers, [^log10 b emin -1 ^]
<pre>
- [ ]</pre>
+ [ ]
+</pre>
FLT_MIN_10_EXP -37
DBL_MIN_10_EXP -37
LDBL_MIN_10_EXP -37
<pre>
FLT_MAX_EXP
DBL_MAX_EXP
- LDBL_MAX_EXP</pre>
+ LDBL_MAX_EXP
+</pre>
<li> maximum integer such that 10 raised to that power is in the range of representable
finite floating-point numbers, [_log10 ((1 - b- p )b emax )_]
<pre>
FLT_MAX_10_EXP +37
DBL_MAX_10_EXP +37
- LDBL_MAX_10_EXP +37</pre>
+ LDBL_MAX_10_EXP +37
+</pre>
</ul>
<p><!--para 12 -->
The values given in the following list shall be replaced by constant expressions with
<pre>
FLT_MAX 1E+37
DBL_MAX 1E+37
- LDBL_MAX 1E+37</pre>
+ LDBL_MAX 1E+37
+</pre>
</ul>
<p><!--para 13 -->
The values given in the following list shall be replaced by constant expressions with
<pre>
FLT_EPSILON 1E-5
DBL_EPSILON 1E-9
- LDBL_EPSILON 1E-9</pre>
+ LDBL_EPSILON 1E-9
+</pre>
<li> minimum normalized positive floating-point number, b emin -1
<!--page 51 -->
<pre>
FLT_MIN 1E-37
DBL_MIN 1E-37
- LDBL_MIN 1E-37</pre>
+ LDBL_MIN 1E-37
+</pre>
<li> minimum positive floating-point number<sup><a href="#note27"><b>27)</b></a></sup>
FLT_TRUE_MIN 1E-37
DBL_TRUE_MIN 1E-37
6
x = s16e (Sum) f k 16-k ,
k=1
- -31 <= e <= +32</pre>
+ -31 <= e <= +32
+</pre>
<pre>
FLT_RADIX 16
FLT_MIN_10_EXP -38
FLT_MAX_EXP +32
FLT_MAX 3.40282347E+38F
- FLT_MAX_10_EXP +38</pre>
+ FLT_MAX_10_EXP +38
+</pre>
<p><!--para 16 -->
EXAMPLE 2 The following describes floating-point representations that also meet the requirements for
24
x f = s2e (Sum) f k 2-k ,
k=1
- -125 <= e <= +128</pre>
+ -125 <= e <= +128
+</pre>
<pre>
53
x d = s2e (Sum) f k 2-k ,
k=1
- -1021 <= e <= +1024</pre>
+ -1021 <= e <= +1024
+</pre>
<pre>
FLT_RADIX 2
FLT_MANT_DIG 24
FLT_EPSILON 1.19209290E-07F // decimal constant
FLT_EPSILON 0X1P-23F // hex constant
- FLT_DECIMAL_DIG 9</pre>
+ FLT_DECIMAL_DIG 9
+</pre>
<!--page 52 -->
DBL_MAX_EXP +1024
DBL_MAX 1.7976931348623157E+308 // decimal constant
DBL_MAX 0X1.fffffffffffffP1023 // hex constant
- DBL_MAX_10_EXP +308</pre>
+ DBL_MAX_10_EXP +308
+</pre>
If a type wider than double were supported, then DECIMAL_DIG would be greater than 17. For
example, if the widest type were to use the minimal-width IEC 60559 double-extended format (64 bits of
precision), then DECIMAL_DIG would be 21.
definitions are listed on separate lines, except when prefaced by the words ''one of''. An
optional symbol is indicated by the subscript ''opt'', so that
<pre>
- { expression<sub>opt</sub> }</pre>
+ { expression<sub>opt</sub> }
+</pre>
indicates an optional expression enclosed in braces.
<p><!--para 2 -->
When syntactic categories are referred to in the main text, they are not italicized and
<pre>
CHAR_BIT
- - 1.</pre>
+ - 1.
+</pre>
</small>
<p><small><a name="note50" href="#note50">50)</a> 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.
EXAMPLE Given the following two file scope declarations:
<pre>
int f(int (*)(), double (*)[3]);
- int f(int (*)(char *), double (*)[]);</pre>
+ int f(int (*)(char *), double (*)[]);
+</pre>
The resulting composite type for the function is:
<pre>
- int f(int (*)(char *), double (*)[3]);</pre>
+ int f(int (*)(char *), double (*)[3]);
+</pre>
<h6>footnotes</h6>
the operand with unsigned integer type is converted to the type of the
operand with signed integer type.
Otherwise, both operands are converted to the unsigned integer type
- corresponding to the type of the operand with signed integer type.</pre>
+ corresponding to the type of the operand with signed integer type.
+</pre>
<p><!--para 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
character-constant
string-literal
punctuator
- each non-white-space character that cannot be one of the above</pre>
+ each non-white-space character that cannot be one of the above
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Each preprocessing token that is converted to a token shall have the lexical form of a
enum static _Noreturn
extern struct _Static_assert
float switch _Thread_local
- for typedef</pre>
+ for typedef
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
The above tokens (case sensitive) are reserved (in translation phases 7 and 8) for use as
A B C D E F G H I J K L M
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</pre>
+ 0 1 2 3 4 5 6 7 8 9
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
An identifier is a sequence of nondigit characters (including the underscore _, the
The identifier __func__ shall be implicitly declared by the translator as if,
immediately following the opening brace of each function definition, the declaration
<pre>
- static const char __func__[] = "function-name";</pre>
+ static const char __func__[] = "function-name";
+</pre>
appeared, where function-name is the name of the lexically-enclosing function.<sup><a href="#note72"><b>72)</b></a></sup>
<p><!--para 2 -->
This name is encoded as if the implicit declaration had been written in the source
{
printf("%s\n", __func__);
/* ... */
- }</pre>
+ }
+</pre>
Each time the function is called, it will print to the standard output stream:
<pre>
- myfunc</pre>
+ myfunc
+</pre>
<p><b> Forward references</b>: function definitions (<a href="#6.9.1">6.9.1</a>).
\U hex-quad hex-quad
hex-quad:
hexadecimal-digit hexadecimal-digit
- hexadecimal-digit hexadecimal-digit</pre>
+ hexadecimal-digit hexadecimal-digit
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
A universal character name shall not specify a character whose short identifier is less than
integer-constant
floating-constant
enumeration-constant
- character-constant</pre>
+ character-constant
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Each constant shall have a type and the value of a constant shall be in the range of
long-suffix: one of
l L
long-long-suffix: one of
- ll LL</pre>
+ ll LL
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
An integer constant begins with a digit, but has no period or exponent part. It may have a
be represented.
<!--page 82 -->
<pre>
- Octal or Hexadecimal</pre>
+ Octal or Hexadecimal
+</pre>
Suffix Decimal Constant Constant
none int int
long long int long int
unsigned long int
long long int
- unsigned long long int</pre>
+ unsigned long long int
+</pre>
u or U unsigned int unsigned int
<pre>
unsigned long int unsigned long int
- unsigned long long int unsigned long long int</pre>
+ unsigned long long int unsigned long long int
+</pre>
l or L long int long int
<pre>
long long int unsigned long int
long long int
- unsigned long long int</pre>
+ unsigned long long int
+</pre>
Both u or U unsigned long int unsigned long int
and l or L unsigned long long int unsigned long long int
ll or LL long long int long long int
<pre>
- unsigned long long int</pre>
+ unsigned long long int
+</pre>
Both u or U unsigned long long int unsigned long long int
and ll or LL
hexadecimal-digit
hexadecimal-digit-sequence hexadecimal-digit
floating-suffix: one of
- f l F L</pre>
+ f l F L
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
A floating constant has a significand part that may be followed by an exponent part and a
<p><!--para 1 -->
<pre>
enumeration-constant:
- identifier</pre>
+ identifier
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
An identifier declared as an enumeration constant has type int.
\ octal-digit octal-digit octal-digit
hexadecimal-escape-sequence:
\x hexadecimal-digit
- hexadecimal-escape-sequence hexadecimal-digit</pre>
+ hexadecimal-escape-sequence hexadecimal-digit
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
An integer character constant is a sequence of one or more multibyte characters enclosed
question mark ? \?
backslash \ \\
octal character \octal digits
- hexadecimal character \x hexadecimal digits</pre>
+ hexadecimal character \x hexadecimal digits
+</pre>
<p><!--para 4 -->
The double-quote " and question-mark ? are representable either by themselves or by the
escape sequences \" and \?, respectively, but the single-quote ' and the backslash \
none unsigned char
L the unsigned type corresponding to wchar_t
u char16_t
- U char32_t</pre>
+ U char32_t
+</pre>
<h6>Semantics</h6>
<p><!--para 10 -->
An integer character constant has type int. The value of an integer character constant
s-char:
any member of the source character set except
the double-quote ", backslash \, or new-line character
- escape-sequence</pre>
+ escape-sequence
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
A sequence of adjacent string literal tokens shall not include both a wide string literal and
<p><!--para 8 -->
EXAMPLE 1 This pair of adjacent character string literals
<pre>
- "\x12" "3"</pre>
+ "\x12" "3"
+</pre>
produces a single character string literal containing the two characters whose values are '\x12' and '3',
because escape sequences are converted into single members of the execution character set just prior to
adjacent string literal concatenation.
"a" "b" L"c"
"a" L"b" "c"
L"a" "b" L"c"
- L"a" L"b" L"c"</pre>
+ L"a" L"b" L"c"
+</pre>
is equivalent to the string literal
<pre>
- L"abc"</pre>
+ L"abc"
+</pre>
Likewise, each of the sequences
<pre>
"a" "b" u"c"
"a" u"b" "c"
u"a" "b" u"c"
- u"a" u"b" u"c"</pre>
+ u"a" u"b" u"c"
+</pre>
is equivalent to
<pre>
- u"abc"</pre>
+ u"abc"
+</pre>
<p><b> Forward references</b>: 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>).
? : ; ...
= *= /= %= += -= <<= >>= &= ^= |=
, # ##
- <: :> <% %> %: %:%:</pre>
+ <: :> <% %> %: %:%:
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
A punctuator is a symbol that has independent syntactic and semantic significance.
<p><!--para 3 -->
In all aspects of the language, the six tokens<sup><a href="#note79"><b>79)</b></a></sup>
<pre>
- <: :> <% %> %: %:%:</pre>
+ <: :> <% %> %: %:%:
+</pre>
behave, respectively, the same as the six tokens
<pre>
- [ ] { } # ##</pre>
+ [ ] { } # ##
+</pre>
except for their spelling.<sup><a href="#note80"><b>80)</b></a></sup>
<p><b> Forward references</b>: 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>).
q-char-sequence q-char
q-char:
any member of the source character set except
- the new-line character and "</pre>
+ the new-line character and "
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
The sequences in both forms of header names are mapped in an implementation-defined
<pre>
0x3<1/a.h>1e2
#include <1/a.h>
- #define const.member@$</pre>
+ #define const.member@$
+</pre>
forms the following sequence of preprocessing tokens (with each individual preprocessing token delimited
by a { on the left and a } on the right).
<pre>
{0x3}{<}{1}{/}{a}{.}{h}{>}{1e2}
{#}{include} {<1/a.h>}
- {#}{define} {const}{.}{member}{@}{$}</pre>
+ {#}{define} {const}{.}{member}{@}{$}
+</pre>
<p><b> Forward references</b>: source file inclusion (<a href="#6.10.2">6.10.2</a>).
pp-number E sign
pp-number p sign
pp-number P sign
- pp-number .</pre>
+ pp-number .
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
A preprocessing number begins with a digit optionally preceded by a period (.) and may
glue(/,/) k(); // syntax error, not comment
/*//*/ l(); // equivalent to l();
m = n//**/o
- + p; // equivalent to m = n + p;</pre>
+ + p; // equivalent to m = n + p;
+</pre>
<pre>
i = ++i + 1;
- a[i++] = i;</pre>
+ a[i++] = i;
+</pre>
while allowing
<pre>
i = i + 1;
- a[i] = i;</pre>
+ a[i] = i;
+</pre>
</small>
<p><small><a name="note85" href="#note85">85)</a> The syntax specifies the precedence of operators in the evaluation of an expression, which is the same
constant
string-literal
( expression )
- generic-selection</pre>
+ generic-selection
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
An identifier is a primary expression, provided it has been declared as designating an
generic-assoc-list , generic-association
generic-association:
type-name : assignment-expression
- default : assignment-expression</pre>
+ default : assignment-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
A generic selection shall have no more than one default generic association. The type
long double: cbrtl, \
default: cbrt, \
float: cbrtf \
- )(X)</pre>
+ )(X)
+</pre>
<h4><a name="6.5.2" href="#6.5.2">6.5.2 Postfix operators</a></h4>
( type-name ) { initializer-list , }
argument-expression-list:
assignment-expression
- argument-expression-list , assignment-expression</pre>
+ argument-expression-list , assignment-expression
+</pre>
<h5><a name="6.5.2.1" href="#6.5.2.1">6.5.2.1 Array subscripting</a></h5>
<h6>Constraints</h6>
<p><!--para 4 -->
EXAMPLE Consider the array object defined by the declaration
<pre>
- int x[3][5];</pre>
+ int x[3][5];
+</pre>
Here x is a 3 x 5 array of ints; more precisely, x is an array of three element objects, each of which is an
array of five ints. In the expression x[i], which is equivalent to (*((x)+(i))), x is first converted to
a pointer to the initial array of five ints. Then i is adjusted according to the type of x, which conceptually
<p><!--para 12 -->
EXAMPLE In the function call
<pre>
- (*pf[f1()]) (f2(), f3() + f4())</pre>
+ (*pf[f1()]) (f2(), f3() + f4())
+</pre>
the functions f1, f2, f3, and f4 may be called in any order. All side effects have to be completed before
the function pointed to by pf[f1()] is called.
struct s { int i; const int ci; };
struct s s;
const struct s cs;
- volatile struct s vs;</pre>
+ volatile struct s vs;
+</pre>
the various members have the types:
<pre>
s.i int
cs.i const int
cs.ci const int
vs.i volatile int
- vs.ci volatile const int</pre>
+ vs.ci volatile const int
+</pre>
/* ... */
if (u.n.alltypes == 1)
if (sin(u.nf.doublenode) == 0.0)
- /* ... */</pre>
+ /* ... */
+</pre>
The following is not a valid fragment (because the union type is not visible within function f):
<pre>
struct t1 { int m; };
} u;
/* ... */
return f(&u.s1, &u.s2);
- }</pre>
+ }
+</pre>
<p><b> Forward references</b>: 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>).
T result = E;
do {
tmp = result + 1;
- } while (!atomic_compare_exchange_strong(&E, &result, tmp));</pre>
+ } while (!atomic_compare_exchange_strong(&E, &result, tmp));
+</pre>
with result being the result of the operation.
</small>
<p><!--para 8 -->
EXAMPLE 1 The file scope definition
<pre>
- int *p = (int []){2, 4};</pre>
+ int *p = (int []){2, 4};
+</pre>
initializes p to point to the first element of an array of two ints, the first having the value two and the
second, four. The expressions in this compound literal are required to be constant. The unnamed object
has static storage duration.
/*...*/
p = (int [2]){*p};
/*...*/
- }</pre>
+ }
+</pre>
p is assigned the address of the first element of an array of two ints, the first having the value previously
pointed to by p and the second, zero. The expressions in this compound literal need not be constant. The
unnamed object has automatic storage duration.
created using compound literals can be passed to functions without depending on member order:
<pre>
drawline((struct point){.x=1, .y=1},
- (struct point){.x=3, .y=4});</pre>
+ (struct point){.x=3, .y=4});
+</pre>
Or, if drawline instead expected pointers to struct point:
<!--page 105 -->
<pre>
drawline(&(struct point){.x=1, .y=1},
- &(struct point){.x=3, .y=4});</pre>
+ &(struct point){.x=3, .y=4});
+</pre>
<p><!--para 11 -->
EXAMPLE 4 A read-only compound literal can be specified through constructions like:
<pre>
- (const float []){1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6}</pre>
+ (const float []){1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6}
+</pre>
<p><!--para 12 -->
EXAMPLE 5 The following three expressions have different meanings:
<pre>
"/tmp/fileXXXXXX"
(char []){"/tmp/fileXXXXXX"}
- (const char []){"/tmp/fileXXXXXX"}</pre>
+ (const char []){"/tmp/fileXXXXXX"}
+</pre>
The first always has static storage duration and has type array of char, but need not be modifiable; the last
two have automatic storage duration when they occur within the body of a function, and the first of these
two is modifiable.
EXAMPLE 6 Like string literals, const-qualified compound literals can be placed into read-only memory
and can even be shared. For example,
<pre>
- (const char []){"abc"} == "abc"</pre>
+ (const char []){"abc"} == "abc"
+</pre>
might yield 1 if the literals' storage is shared.
<p><!--para 14 -->
<pre>
struct int_list { int car; struct int_list *cdr; };
struct int_list endless_zeros = {0, &endless_zeros};
- eval(endless_zeros);</pre>
+ eval(endless_zeros);
+</pre>
<p><!--para 15 -->
EXAMPLE 8 Each compound literal creates only a single object in a given scope:
q = p, p = &((struct s){ j++ });
if (j < 2) goto again;
return p == q && q->i == 1;
- }</pre>
+ }
+</pre>
The function f() always returns the value 1.
<p><!--para 16 -->
Note that if an iteration statement were used instead of an explicit goto and a labeled statement, the
sizeof ( type-name )
alignof ( type-name )
unary-operator: one of
- & * + - ~ !</pre>
+ & * + - ~ !
+</pre>
<h5><a name="6.5.3.1" href="#6.5.3.1">6.5.3.1 Prefix increment and decrement operators</a></h5>
<h6>Constraints</h6>
allocate and return a pointer to void. For example:
<pre>
extern void *alloc(size_t);
- double *dp = alloc(sizeof *dp);</pre>
+ double *dp = alloc(sizeof *dp);
+</pre>
The implementation of the alloc function should ensure that its return value is aligned suitably for
conversion to a pointer to double.
<p><!--para 7 -->
EXAMPLE 2 Another use of the sizeof operator is to compute the number of elements in an array:
<pre>
- sizeof array / sizeof array[0]</pre>
+ sizeof array / sizeof array[0]
+</pre>
<p><!--para 8 -->
EXAMPLE 3 In this example, the size of a variable length array is computed and returned from a
function:
<pre>
- #include <a href="#7.19"><stddef.h></a></pre>
+ #include <a href="#7.19"><stddef.h></a>
+</pre>
size_t size;
size = fsize3(10); // fsize3 returns 13
return 0;
- }</pre>
+ }
+</pre>
<p><b> Forward references</b>: 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>).
<pre>
cast-expression:
unary-expression
- ( type-name ) cast-expression</pre>
+ ( type-name ) cast-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Unless the type name specifies a void type, the type name shall specify atomic, qualified,
cast-expression
multiplicative-expression * cast-expression
multiplicative-expression / cast-expression
- multiplicative-expression % cast-expression</pre>
+ multiplicative-expression % cast-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Each of the operands shall have arithmetic type. The operands of the % operator shall
additive-expression:
multiplicative-expression
additive-expression + multiplicative-expression
- additive-expression - multiplicative-expression</pre>
+ additive-expression - multiplicative-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
For addition, either both operands shall have arithmetic type, or one operand shall be a
p += 1; // p == &a[1]
(*p)[2] = 99; // a[1][2] == 99
n = p - a; // n == 1
- }</pre>
+ }
+</pre>
<p><!--para 11 -->
If array a in the above example were declared to be an array of known constant size, and pointer p were
declared to be a pointer to an array of the same known constant size (pointing to a), the results would be
shift-expression:
additive-expression
shift-expression << additive-expression
- shift-expression >> additive-expression</pre>
+ shift-expression >> additive-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Each of the operands shall have integer type.
relational-expression < shift-expression
relational-expression > shift-expression
relational-expression <= shift-expression
- relational-expression >= shift-expression</pre>
+ relational-expression >= shift-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
One of the following shall hold:
equality-expression:
relational-expression
equality-expression == relational-expression
- equality-expression != relational-expression</pre>
+ equality-expression != relational-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
One of the following shall hold:
<pre>
AND-expression:
equality-expression
- AND-expression & equality-expression</pre>
+ AND-expression & equality-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Each of the operands shall have integer type.
<pre>
exclusive-OR-expression:
AND-expression
- exclusive-OR-expression ^ AND-expression</pre>
+ exclusive-OR-expression ^ AND-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Each of the operands shall have integer type.
<pre>
inclusive-OR-expression:
exclusive-OR-expression
- inclusive-OR-expression | exclusive-OR-expression</pre>
+ inclusive-OR-expression | exclusive-OR-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Each of the operands shall have integer type.
<pre>
logical-AND-expression:
inclusive-OR-expression
- logical-AND-expression && inclusive-OR-expression</pre>
+ logical-AND-expression && inclusive-OR-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Each of the operands shall have scalar type.
<pre>
logical-OR-expression:
logical-AND-expression
- logical-OR-expression || logical-AND-expression</pre>
+ logical-OR-expression || logical-AND-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Each of the operands shall have scalar type.
<pre>
conditional-expression:
logical-OR-expression
- logical-OR-expression ? expression : conditional-expression</pre>
+ logical-OR-expression ? expression : conditional-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
The first operand shall have scalar type.
const int *c_ip;
volatile int *v_ip;
int *ip;
- const char *c_cp;</pre>
+ const char *c_cp;
+</pre>
the third column in the following table is the common type that is the result of a conditional expression in
which the first two columns are the second and third operands (in either order):
<pre>
c_ip v_ip const volatile int *
vp c_cp const void *
ip c_ip const int *
- vp ip void *</pre>
+ vp ip void *
+</pre>
<h6>footnotes</h6>
conditional-expression
unary-expression assignment-operator assignment-expression
assignment-operator: one of
- = *= /= %= += -= <<= >>= &= ^= |=</pre>
+ = *= /= %= += -= <<= >>= &= ^= |=
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
An assignment operator shall have a modifiable lvalue as its left operand.
char c;
/* ... */
if ((c = f()) == -1)
- /* ... */</pre>
+ /* ... */
+</pre>
the int value returned by the function may be truncated when stored in the char, and then converted back
to int width prior to the comparison. In an implementation in which ''plain'' char has the same range of
values as unsigned char (and char is narrower than int), the result of the conversion cannot be
char c;
int i;
long l;
- l = (c = i);</pre>
+ l = (c = i);
+</pre>
the value of i is converted to the type of the assignment expression c = i, that is, char type. The value
of the expression enclosed in parentheses is then converted to the type of the outer assignment expression,
that is, long int type.
const char c = 'A';
cpp = &p; // constraint violation
*cpp = &c; // valid
- *p = 0; // valid</pre>
+ *p = 0; // valid
+</pre>
The first assignment is unsafe because it would allow the following valid code to attempt to change the
value of the const object c.
T result;
do {
result = tmp op (E2);
- } while (!atomic_compare_exchange_strong(&E1, &tmp, result));</pre>
+ } while (!atomic_compare_exchange_strong(&E1, &tmp, result));
+</pre>
with result being the result of the operation.
</small>
<pre>
expression:
assignment-expression
- expression , assignment-expression</pre>
+ expression , assignment-expression
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
The left operand of a comma operator is evaluated as a void expression; there is a
of initializers). On the other hand, it can be used within a parenthesized expression or within the second
expression of a conditional operator in such contexts. In the function call
<pre>
- f(a, (t=3, t+2), c)</pre>
+ f(a, (t=3, t+2), c)
+</pre>
the function has three arguments, the second of which has the value 5.
<p><b> Forward references</b>: initialization (<a href="#6.7.9">6.7.9</a>).
<p><!--para 1 -->
<pre>
constant-expression:
- conditional-expression</pre>
+ conditional-expression
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
A constant expression can be evaluated during translation rather than runtime, and
<p><small><a name="note118" href="#note118">118)</a> Thus, in the following initialization,
<pre>
- static int i = 2 || 1 / 0;</pre>
+ static int i = 2 || 1 / 0;
+</pre>
the expression is a valid integer constant expression with value one.
</small>
init-declarator-list , init-declarator
init-declarator:
declarator
- declarator = initializer</pre>
+ declarator = initializer
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
A declaration other than a static_assert declaration shall declare at least a declarator
static
_Thread_local
auto
- register</pre>
+ register
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
At most, one storage-class specifier may be given in the declaration specifiers in a
atomic-type-specifier
struct-or-union-specifier
enum-specifier
- typedef-name</pre>
+ typedef-name
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
At least one type specifier shall be given in the declaration specifiers in each declaration,
struct-declarator-list , struct-declarator
struct-declarator:
declarator
- declarator<sub>opt</sub> : constant-expression</pre>
+ declarator<sub>opt</sub> : constant-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
A struct-declaration that does not declare an anonymous structure or anonymous union
} v1;
v1.i = 2; // valid
v1.k = 3; // invalid: inner structure is not anonymous
- v1.w.k = 5; // valid</pre>
+ v1.w.k = 5; // valid
+</pre>
<p><!--para 20 -->
EXAMPLE 2 After the declaration:
<pre>
- struct s { int n; double d[]; };</pre>
+ struct s { int n; double d[]; };
+</pre>
the structure struct s has a flexible array member d. A typical way to use this is:
<pre>
int m = /* some value */;
- struct s *p = malloc(sizeof (struct s) + sizeof (double [m]));</pre>
+ struct s *p = malloc(sizeof (struct s) + sizeof (double [m]));
+</pre>
and assuming that the call to malloc succeeds, the object pointed to by p behaves, for most purposes, as if
p had been declared as:
<pre>
- struct { int n; double d[m]; } *p;</pre>
+ struct { int n; double d[m]; } *p;
+</pre>
(there are circumstances in which this equivalence is broken; in particular, the offsets of member d might
not be the same).
<p><!--para 21 -->
struct s t1 = { 0 }; // valid
struct s t2 = { 1, { <a href="#4.2">4.2</a> }}; // invalid
t1.n = 4; // valid
- t1.d[0] = <a href="#4.2">4.2</a>; // might be undefined behavior</pre>
+ t1.d[0] = <a href="#4.2">4.2</a>; // might be undefined behavior
+</pre>
The initialization of t2 is invalid (and violates a constraint) because struct s is treated as if it did not
contain member d. The assignment to t1.d[0] is probably undefined behavior, but it is possible that
<pre>
- sizeof (struct s) >= offsetof(struct s, d) + sizeof (double)</pre>
+ sizeof (struct s) >= offsetof(struct s, d) + sizeof (double)
+</pre>
in which case the assignment would be legitimate. Nevertheless, it cannot appear in strictly conforming
code.
<!--page 133 -->
<p><!--para 22 -->
After the further declaration:
<pre>
- struct ss { int n; };</pre>
+ struct ss { int n; };
+</pre>
the expressions:
<pre>
sizeof (struct s) >= sizeof (struct ss)
- sizeof (struct s) >= offsetof(struct s, d)</pre>
+ sizeof (struct s) >= offsetof(struct s, d)
+</pre>
are always equal to 1.
<p><!--para 23 -->
If sizeof (double) is 8, then after the following code is executed:
struct s *s1;
struct s *s2;
s1 = malloc(sizeof (struct s) + 64);
- s2 = malloc(sizeof (struct s) + 46);</pre>
+ s2 = malloc(sizeof (struct s) + 46);
+</pre>
and assuming that the calls to malloc succeed, the objects pointed to by s1 and s2 behave, for most
purposes, as if the identifiers had been declared as:
<pre>
struct { int n; double d[8]; } *s1;
- struct { int n; double d[5]; } *s2;</pre>
+ struct { int n; double d[5]; } *s2;
+</pre>
<p><!--para 24 -->
Following the further successful assignments:
<pre>
s1 = malloc(sizeof (struct s) + 10);
- s2 = malloc(sizeof (struct s) + 6);</pre>
+ s2 = malloc(sizeof (struct s) + 6);
+</pre>
they then behave as if the declarations were:
<pre>
- struct { int n; double d[1]; } *s1, *s2;</pre>
+ struct { int n; double d[1]; } *s1, *s2;
+</pre>
and:
<pre>
double *dp;
dp = &(s1->d[0]); // valid
*dp = 42; // valid
dp = &(s2->d[0]); // valid
- *dp = 42; // undefined behavior</pre>
+ *dp = 42; // undefined behavior
+</pre>
<p><!--para 25 -->
The assignment:
<pre>
- *s1 = *s2;</pre>
+ *s1 = *s2;
+</pre>
only copies the member n; if any of the array elements are within the first sizeof (struct s) bytes
of the structure, they might be copied or simply overwritten with indeterminate values.
enumerator-list , enumerator
enumerator:
enumeration-constant
- enumeration-constant = constant-expression</pre>
+ enumeration-constant = constant-expression
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
The expression that defines the value of an enumeration constant shall be an integer
col = claret;
cp = &col;
if (*cp != burgundy)
- /* ... */</pre>
+ /* ... */
+</pre>
makes hue the tag of an enumeration, and then declares col as an object that has that type and cp as a
pointer to an object that has that type. The enumerated values are in the set { 0, 1, 20, 21 }.
<p><!--para 3 -->
A type specifier of the form
<pre>
- enum identifier</pre>
+ enum identifier
+</pre>
without an enumerator list shall only appear after the type it specifies is complete.
<h6>Semantics</h6>
<p><!--para 4 -->
<!--page 136 -->
<pre>
- struct-or-union identifier<sub>opt</sub> { struct-declaration-list }</pre>
+ struct-or-union identifier<sub>opt</sub> { struct-declaration-list }
+</pre>
or
<pre>
- enum identifier<sub>opt</sub> { enumerator-list }</pre>
+ enum identifier<sub>opt</sub> { enumerator-list }
+</pre>
or
<pre>
- enum identifier<sub>opt</sub> { enumerator-list , }</pre>
+ enum identifier<sub>opt</sub> { enumerator-list , }
+</pre>
declares a structure, union, or enumerated type. The list defines the structure content,
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.
<p><!--para 7 -->
A declaration of the form
<pre>
- struct-or-union identifier ;</pre>
+ struct-or-union identifier ;
+</pre>
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>
<p><!--para 8 -->
If a type specifier of the form
<pre>
- struct-or-union identifier</pre>
+ struct-or-union identifier
+</pre>
occurs other than as part of one of the above forms, and no other declaration of the
identifier as a tag is visible, then it declares an incomplete structure or union type, and
declares the identifier as the tag of that type.<sup><a href="#note131"><b>131)</b></a></sup>
<p><!--para 9 -->
If a type specifier of the form
<pre>
- struct-or-union identifier</pre>
+ struct-or-union identifier
+</pre>
or
<pre>
- enum identifier</pre>
+ enum identifier
+</pre>
occurs other than as part of one of the above forms, and a declaration of the identifier as a
tag is visible, then it specifies the same type as that other declaration, and does not
redeclare the tag.
struct tnode {
int count;
struct tnode *left, *right;
- };</pre>
+ };
+</pre>
specifies a structure that contains an integer and two pointers to objects of the same type. Once this
declaration has been given, the declaration
<!--page 137 -->
<pre>
- struct tnode s, *sp;</pre>
+ struct tnode s, *sp;
+</pre>
declares s to be an object of the given type and sp to be a pointer to an object of the given type. With
these declarations, the expression sp->left refers to the left struct tnode pointer of the object to
which sp points; the expression s.right->count designates the count member of the right struct
int count;
TNODE *left, *right;
};
- TNODE s, *sp;</pre>
+ TNODE s, *sp;
+</pre>
<p><!--para 12 -->
EXAMPLE 2 To illustrate the use of prior declaration of a tag to specify a pair of mutually referential
structures, the declarations
<pre>
struct s1 { struct s2 *s2p; /* ... */ }; // D1
- struct s2 { struct s1 *s1p; /* ... */ }; // D2</pre>
+ struct s2 { struct s1 *s1p; /* ... */ }; // D2
+</pre>
specify a pair of structures that contain pointers to each other. Note, however, that if s2 were already
declared as a tag in an enclosing scope, the declaration D1 would refer to it, not to the tag s2 declared in
D2. To eliminate this context sensitivity, the declaration
<pre>
- struct s2;</pre>
+ struct s2;
+</pre>
may be inserted ahead of D1. This declares a new tag s2 in the inner scope; the declaration D2 then
completes the specification of the new type.
<p><!--para 1 -->
<pre>
atomic-type-specifier:
- _Atomic ( type-name )</pre>
+ _Atomic ( type-name )
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Atomic type specifiers shall not be used if the implementation does not support atomic
const
restrict
volatile
- _Atomic</pre>
+ _Atomic
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Types other than pointer types whose referenced type is an object type shall not be
<p><!--para 11 -->
EXAMPLE 1 An object declared
<pre>
- extern const volatile int real_time_clock;</pre>
+ extern const volatile int real_time_clock;
+</pre>
may be modifiable by hardware, but cannot be assigned to, incremented, or decremented.
<p><!--para 12 -->
pi = &ncs.mem; // valid
pi = &cs.mem; // violates type constraints for =
pci = &cs.mem; // valid
- pi = a[0]; // invalid: a[0] has type ''const int *''</pre>
+ pi = a[0]; // invalid: a[0] has type ''const int *''
+</pre>
<p><!--para 13 -->
EXAMPLE 3 The declaration
<pre>
- _Atomic volatile int *p;</pre>
+ _Atomic volatile int *p;
+</pre>
specifies that p has the type ''pointer to volatile atomic int'', a pointer to a volatile-qualified atomic type.
<pre>
int * restrict a;
int * restrict b;
- extern int c[];</pre>
+ extern int c[];
+</pre>
assert that if an object is accessed using one of a, b, or c, and that object is modified anywhere in the
program, then it is never accessed using either of the other two.
{
while (n-- > 0)
*p++ = *q++;
- }</pre>
+ }
+</pre>
assert that, during each execution of the function, if an object is accessed through one of the pointer
parameters, then it is not also accessed through the other.
<p><!--para 9 -->
extern int d[100];
f(50, d + 50, d); // valid
f(50, d + 1, d); // undefined behavior
- }</pre>
+ }
+</pre>
<p><!--para 10 -->
EXAMPLE 3 The function parameter declarations
int i;
for (i = 0; i < n; i++)
p[i] = q[i] + r[i];
- }</pre>
+ }
+</pre>
illustrate how an unmodified object can be aliased through two restricted pointers. In particular, if a and b
are disjoint arrays, a call of the form h(100, a, b, b) has defined behavior, because array b is not
modified within function h.
p1 = q2; // undefined behavior
p2 = q2; // undefined behavior
}
- }</pre>
+ }
+</pre>
<p><!--para 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
t.n = n;
t.v = malloc(n * sizeof (float));
return t;
- }</pre>
+ }
+</pre>
<h6>footnotes</h6>
<pre>
function-specifier:
inline
- _Noreturn</pre>
+ _Noreturn
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Function specifiers shall be used only in the declaration of an identifier for a function.
{
/* A translator may perform inline substitutions */
return is_fahr ? cels(temp) : fahr(temp);
- }</pre>
+ }
+</pre>
<p><!--para 11 -->
Note that the definition of fahr is an external definition because fahr is also declared with extern, but
the definition of cels is an inline definition. Because cels has external linkage and is referenced, an
}
_Noreturn void g (int i) { // causes undefined behavior if i <= 0
if (i > 0) abort();
- }</pre>
+ }
+</pre>
<p><b> Forward references</b>: function definitions (<a href="#6.9.1">6.9.1</a>).
<pre>
alignment-specifier:
_Alignas ( type-name )
- _Alignas ( constant-expression )</pre>
+ _Alignas ( constant-expression )
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
An alignment attribute shall not be specified in a declaration of a typedef, or a bit-field, or
declaration-specifiers abstract-declarator<sub>opt</sub>
identifier-list:
identifier
- identifier-list , identifier</pre>
+ identifier-list , identifier
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
Each declarator declares one identifier, and asserts that when an operand of the same
<p><!--para 4 -->
In the following subclauses, consider a declaration
<pre>
- T D1</pre>
+ T D1
+</pre>
where T contains the declaration specifiers that specify a type T (such as int) and D1 is
a declarator that contains an identifier ident. The type specified for the identifier ident in
the various forms of declarator is described inductively using this notation.
<p><!--para 5 -->
If, in the declaration ''T D1'', D1 has the form
<pre>
- identifier</pre>
+ identifier
+</pre>
then the type specified for ident is T .
<p><!--para 6 -->
If, in the declaration ''T D1'', D1 has the form
<pre>
- ( D )</pre>
+ ( D )
+</pre>
then ident has the type specified by the declaration ''T D''. Thus, a declarator in
parentheses is identical to the unparenthesized declarator, but the binding of complicated
declarators may be altered by parentheses.
<p><!--para 1 -->
If, in the declaration ''T D1'', D1 has the form
<pre>
- * type-qualifier-list<sub>opt</sub> D</pre>
+ * type-qualifier-list<sub>opt</sub> D
+</pre>
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 type-qualifier-list
pointer to T ''. For each type qualifier in the list, ident is a so-qualified pointer.
<!--page 147 -->
<pre>
const int *ptr_to_constant;
- int *const constant_ptr;</pre>
+ int *const constant_ptr;
+</pre>
The contents of any object pointed to by ptr_to_constant shall not be modified through that pointer,
but ptr_to_constant itself may be changed to point to another object. Similarly, the contents of the
int pointed to by constant_ptr may be modified, but constant_ptr itself shall always point to the
type ''pointer to int''.
<pre>
typedef int *int_ptr;
- const int_ptr constant_ptr;</pre>
+ const int_ptr constant_ptr;
+</pre>
declares constant_ptr as an object that has type ''const-qualified pointer to int''.
D[ type-qualifier-list<sub>opt</sub> assignment-expression<sub>opt</sub> ]
D[ static type-qualifier-list<sub>opt</sub> assignment-expression ]
D[ type-qualifier-list static assignment-expression ]
- D[ type-qualifier-list<sub>opt</sub> * ]</pre>
+ D[ type-qualifier-list<sub>opt</sub> * ]
+</pre>
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 ''.<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.)
<p><!--para 7 -->
EXAMPLE 1
<pre>
- float fa[11], *afp[17];</pre>
+ float fa[11], *afp[17];
+</pre>
declares an array of float numbers and an array of pointers to float numbers.
<p><!--para 8 -->
EXAMPLE 2 Note the distinction between the declarations
<pre>
extern int *x;
- extern int y[];</pre>
+ extern int y[];
+</pre>
The first declares x to be a pointer to int; the second declares y to be an array of int of unspecified size
(an incomplete type), the storage for which is defined elsewhere.
p = a; // invalid: not compatible because 4 != 6
r = c; // compatible, but defined behavior only if
// n == 6 and m == n+1
- }</pre>
+ }
+</pre>
int (*s)[m]; // valid: auto pointer to VLA
extern int (*r)[m]; // invalid: r has linkage and points to VLA
static int (*q)[m] = &B; // valid: q is a static block pointer to VLA
- }</pre>
+ }
+</pre>
<p><b> Forward references</b>: 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>).
If, in the declaration ''T D1'', D1 has the form
<!--page 150 -->
<pre>
- D( parameter-type-list )</pre>
+ D( parameter-type-list )
+</pre>
or
<pre>
- D( identifier-list<sub>opt</sub> )</pre>
+ D( identifier-list<sub>opt</sub> )
+</pre>
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 function returning
T ''.
<p><!--para 16 -->
EXAMPLE 1 The declaration
<pre>
- int f(void), *fip(), (*pfi)();</pre>
+ int f(void), *fip(), (*pfi)();
+</pre>
declares a function f with no parameters returning an int, a function fip with no parameter specification
returning a pointer to an int, and a pointer pfi to a function with no parameter specification returning an
int. It is especially useful to compare the last two. The binding of *fip() is *(fip()), so that the
<p><!--para 18 -->
EXAMPLE 2 The declaration
<pre>
- int (*apfi[3])(int *x, int *y);</pre>
+ int (*apfi[3])(int *x, int *y);
+</pre>
declares an array apfi of three pointers to functions returning int. Each of these functions has two
parameters that are pointers to int. The identifiers x and y are declared for descriptive purposes only and
go out of scope at the end of the declaration of apfi.
<p><!--para 19 -->
EXAMPLE 3 The declaration
<pre>
- int (*fpfi(int (*)(long), int))(int, ...);</pre>
+ int (*fpfi(int (*)(long), int))(int, ...);
+</pre>
declares a function fpfi that returns a pointer to a function returning an int. The function fpfi has two
parameters: a pointer to a function returning an int (with one parameter of type long int), and an int.
The pointer returned by fpfi points to a function that has one int parameter and accepts zero or more
for (int j = 0, k = n*m+300; j < k; j++)
// a is a pointer to a VLA with n*m+300 elements
a[i][j] += x;
- }</pre>
+ }
+</pre>
<p><!--para 21 -->
EXAMPLE 5 The following are all compatible function prototype declarators.
double maximum(int n, int m, double a[n][m]);
double maximum(int n, int m, double a[*][*]);
double maximum(int n, int m, double a[ ][*]);
- double maximum(int n, int m, double a[ ][m]);</pre>
+ double maximum(int n, int m, double a[ ][m]);
+</pre>
as are:
<pre>
void f(double (* restrict a)[5]);
void f(double a[restrict][5]);
void f(double a[restrict 3][5]);
- void f(double a[restrict static 3][5]);</pre>
+ void f(double a[restrict static 3][5]);
+</pre>
(Note that the last declaration also specifies that the argument corresponding to a in any call to f must be a
non-null pointer to the first of at least three arrays of 5 doubles, which the others do not.)
direct-abstract-declarator<sub>opt</sub> [ type-qualifier-list static
assignment-expression ]
direct-abstract-declarator<sub>opt</sub> [ * ]
- direct-abstract-declarator<sub>opt</sub> ( parameter-type-list<sub>opt</sub> )</pre>
+ direct-abstract-declarator<sub>opt</sub> ( parameter-type-list<sub>opt</sub> )
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
In several contexts, it is necessary to specify a type. This is accomplished using a type
(e) int (*)[*]
(f) int *()
(g) int (*)(void)
- (h) int (*const [])(unsigned int, ...)</pre>
+ (h) int (*const [])(unsigned int, ...)
+</pre>
name respectively the types (a) int, (b) pointer to int, (c) array of three pointers to int, (d) pointer to an
array of three ints, (e) pointer to a variable length array of an unspecified number of ints, (f) function
with no parameter specification returning a pointer to int, (g) pointer to function with no parameters
<p><!--para 1 -->
<pre>
typedef-name:
- identifier</pre>
+ identifier
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
If a typedef name specifies a variably modified type then it shall have block scope.
synonym for the type so specified. That is, in the following declarations:
<pre>
typedef T type_ident;
- type_ident D;</pre>
+ type_ident D;
+</pre>
type_ident is defined as a typedef name with the type specified by the declaration
specifiers in T (known as T ), and the identifier in D has the type ''derived-declarator-
type-list T '' where the derived-declarator-type-list is specified by the declarators of D. A
EXAMPLE 1 After
<pre>
typedef int MILES, KLICKSP();
- typedef struct { double hi, lo; } range;</pre>
+ typedef struct { double hi, lo; } range;
+</pre>
the constructions
<pre>
MILES distance;
extern KLICKSP *metricp;
range x;
- range z, *zp;</pre>
+ range z, *zp;
+</pre>
are all valid declarations. The type of distance is int, that of metricp is ''pointer to function with no
parameter specification returning int'', and that of x and z is the specified structure; zp is a pointer to
such a structure. The object distance has a type compatible with any other int object.
EXAMPLE 2 After the declarations
<pre>
typedef struct s1 { int x; } t1, *tp1;
- typedef struct s2 { int x; } t2, *tp2;</pre>
+ typedef struct s2 { int x; } t2, *tp2;
+</pre>
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.
<!--page 155 -->
unsigned t:4;
const t:5;
plain r:5;
- };</pre>
+ };
+</pre>
declare a typedef name t with type signed int, a typedef name plain with type int, and a structure
with three bit-field members, one named t that contains values in the range [0, 15], an unnamed const-
qualified bit-field which (if it could be accessed) would contain values in either the range [-15, +15] or
in an inner scope by
<pre>
t f(t (t));
- long t;</pre>
+ long t;
+</pre>
then a function f is declared with type ''function returning signed int with one unnamed parameter
with type pointer to function returning signed int with one unnamed parameter with type signed
int'', and an identifier t with type long int.
typedef void fv(int), (*pfv)(int);
void (*signal(int, void (*)(int)))(int);
fv *signal(int, fv *);
- pfv signal(int, pfv);</pre>
+ pfv signal(int, pfv);
+</pre>
<p><!--para 8 -->
EXAMPLE 5 If a typedef name denotes a variable length array type, the length of the array is fixed at the
int b[n]; // a and b are different sizes
for (int i = 1; i < n; i++)
a[i-1] = b[i];
- }</pre>
+ }
+</pre>
<h4><a name="6.7.9" href="#6.7.9">6.7.9 Initialization</a></h4>
<h6>Syntax</h6>
designator-list designator
designator:
[ constant-expression ]
- . identifier</pre>
+ . identifier
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
No initializer shall attempt to provide a value for an object not contained within the entity
<p><!--para 6 -->
If a designator has the form
<pre>
- [ constant-expression ]</pre>
+ [ constant-expression ]
+</pre>
then the current object (defined below) shall have array type and the expression shall be
an integer constant expression. If the array is of unknown size, any nonnegative value is
valid.
<p><!--para 7 -->
If a designator has the form
<pre>
- . identifier</pre>
+ . identifier
+</pre>
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.
<!--page 157 -->
EXAMPLE 1 Provided that <a href="#7.3"><complex.h></a> has been #included, the declarations
<pre>
int i = <a href="#3.5">3.5</a>;
- double complex c = 5 + 3 * I;</pre>
+ double complex c = 5 + 3 * I;
+</pre>
define and initialize i with the value 3 and c with the value 5.0 + i3.0.
<p><!--para 25 -->
EXAMPLE 2 The declaration
<pre>
- int x[] = { 1, 3, 5 };</pre>
+ int x[] = { 1, 3, 5 };
+</pre>
defines and initializes x as a one-dimensional array object that has three elements, as no size was specified
and there are three initializers.
{ 1, 3, 5 },
{ 2, 4, 6 },
{ 3, 5, 7 },
- };</pre>
+ };
+</pre>
is a definition with a fully bracketed initialization: 1, 3, and 5 initialize the first row of y (the array object
y[0]), namely y[0][0], y[0][1], and y[0][2]. Likewise the next two lines initialize y[1] and
y[2]. The initializer ends early, so y[3] is initialized with zeros. Precisely the same effect could have
<pre>
int y[4][3] = {
1, 3, 5, 2, 4, 6, 3, 5, 7
- };</pre>
- The initializer for y[0] does not begin with a left brace, so three items from the list are used. Likewise the
+ };
+</pre>
+ The initializer for y[0] does not begin with a left brace, so three items from the list are used. Likewise the
next three are taken successively for y[1] and y[2].
<p><!--para 27 -->
<pre>
int z[4][3] = {
{ 1 }, { 2 }, { 3 }, { 4 }
- };</pre>
+ };
+</pre>
initializes the first column of z as specified and initializes the rest with zeros.
<p><!--para 28 -->
EXAMPLE 5 The declaration
<pre>
- struct { int a[3], b; } w[] = { { 1 }, 2 };</pre>
+ struct { int a[3], b; } w[] = { { 1 }, 2 };
+</pre>
is a definition with an inconsistently bracketed initialization. It defines an array with two element
{ 1 },
{ 2, 3 },
{ 4, 5, 6 }
- };</pre>
+ };
+</pre>
contains an incompletely but consistently bracketed initialization. It defines a three-dimensional array
object: q[0][0][0] is 1, q[1][0][0] is 2, q[1][0][1] is 3, and 4, 5, and 6 initialize
q[2][0][0], q[2][0][1], and q[2][1][0], respectively; all the rest are zero. The initializer for
1, 0, 0, 0, 0, 0,
2, 3, 0, 0, 0, 0,
4, 5, 6
- };</pre>
+ };
+</pre>
or by:
<pre>
short q[4][3][2] = {
{ 4, 5 },
{ 6 },
}
- };</pre>
+ };
+</pre>
in a fully bracketed form.
<p><!--para 30 -->
Note that the fully bracketed and minimally bracketed forms of initialization are, in general, less likely to
EXAMPLE 7 One form of initialization that completes array types involves typedef names. Given the
declaration
<pre>
- typedef int A[]; // OK - declared with block scope</pre>
+ typedef int A[]; // OK - declared with block scope
+</pre>
the declaration
<pre>
- A a = { 1, 2 }, b = { 3, 4, 5 };</pre>
+ A a = { 1, 2 }, b = { 3, 4, 5 };
+</pre>
is identical to
<pre>
- int a[] = { 1, 2 }, b[] = { 3, 4, 5 };</pre>
+ int a[] = { 1, 2 }, b[] = { 3, 4, 5 };
+</pre>
due to the rules for incomplete types.
<!--page 161 -->
<p><!--para 32 -->
EXAMPLE 8 The declaration
<pre>
- char s[] = "abc", t[3] = "abc";</pre>
+ char s[] = "abc", t[3] = "abc";
+</pre>
defines ''plain'' char array objects s and t whose elements are initialized with character string literals.
This declaration is identical to
<pre>
char s[] = { 'a', 'b', 'c', '\0' },
- t[] = { 'a', 'b', 'c' };</pre>
+ t[] = { 'a', 'b', 'c' };
+</pre>
The contents of the arrays are modifiable. On the other hand, the declaration
<pre>
- char *p = "abc";</pre>
+ char *p = "abc";
+</pre>
defines p with type ''pointer to char'' and initializes it to point to an object with type ''array of char''
with length 4 whose elements are initialized with a character string literal. If an attempt is made to use p to
modify the contents of the array, the behavior is undefined.
const char *nm[] = {
[member_two] = "member two",
[member_one] = "member one",
- };</pre>
+ };
+</pre>
<p><!--para 34 -->
EXAMPLE 10 Structure members can be initialized to nonzero values without depending on their order:
<pre>
- div_t answer = { .quot = 2, .rem = -1 };</pre>
+ div_t answer = { .quot = 2, .rem = -1 };
+</pre>
<p><!--para 35 -->
EXAMPLE 11 Designators can be used to provide explicit initialization when unadorned initializer lists
might be misunderstood:
<pre>
struct { int a[3], b; } w[] =
- { [0].a = {1}, [1].a[0] = 2 };</pre>
+ { [0].a = {1}, [1].a[0] = 2 };
+</pre>
<p><!--para 36 -->
EXAMPLE 12 Space can be ''allocated'' from both ends of an array by using a single designator:
<pre>
int a[MAX] = {
1, 3, 5, 7, 9, [MAX-5] = 8, 6, 4, 2, 0
- };</pre>
+ };
+</pre>
<p><!--para 37 -->
In the above, if MAX is greater than ten, there will be some zero-valued elements in the middle; if it is less
than ten, some of the values provided by the first five initializers will be overridden by the second five.
<p><!--para 38 -->
EXAMPLE 13 Any member of a union can be initialized:
<pre>
- union { /* ... */ } u = { .any_member = 42 };</pre>
+ union { /* ... */ } u = { .any_member = 42 };
+</pre>
<p><b> Forward references</b>: common definitions <a href="#7.19"><stddef.h></a> (<a href="#7.19">7.19</a>).
<!--page 162 -->
<p><!--para 1 -->
<pre>
static_assert-declaration:
- _Static_assert ( constant-expression , string-literal ) ;</pre>
+ _Static_assert ( constant-expression , string-literal ) ;
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
The constant expression shall compare unequal to 0.
expression-statement
selection-statement
iteration-statement
- jump-statement</pre>
+ jump-statement
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
A statement specifies an action to be performed. Except as indicated, statements are
labeled-statement:
identifier : statement
case constant-expression : statement
- default : statement</pre>
+ default : statement
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
A case or default label shall appear only in a switch statement. Further
block-item-list block-item
block-item:
declaration
- statement</pre>
+ statement
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
A compound statement is a block.
<p><!--para 1 -->
<pre>
expression-statement:
- expression<sub>opt</sub> ;</pre>
+ expression<sub>opt</sub> ;
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
The expression in an expression statement is evaluated as a void expression for its side
<pre>
int p(int);
/* ... */
- (void)p(0);</pre>
+ (void)p(0);
+</pre>
char *s;
/* ... */
while (*s++ != '\0')
- ;</pre>
+ ;
+</pre>
a null statement is used to supply an empty loop body to the iteration statement.
<p><!--para 6 -->
}
/* ... */
end_loop1: ;
- }</pre>
+ }
+</pre>
<p><b> Forward references</b>: iteration statements (<a href="#6.8.5">6.8.5</a>).
selection-statement:
if ( expression ) statement
if ( expression ) statement else statement
- switch ( expression ) statement</pre>
+ switch ( expression ) statement
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
A selection statement selects among a set of statements depending on the value of a
/* falls through into default code */
default:
printf("%d\n", i);
- }</pre>
+ }
+</pre>
the object whose identifier is i exists with automatic storage duration (within the block) but is never
initialized, and thus if the controlling expression has a nonzero value, the call to the printf function will
access an indeterminate value. Similarly, the call to the function f cannot be reached.
while ( expression ) statement
do statement while ( expression ) ;
for ( expression<sub>opt</sub> ; expression<sub>opt</sub> ; expression<sub>opt</sub> ) statement
- for ( declaration expression<sub>opt</sub> ; expression<sub>opt</sub> ) statement</pre>
+ for ( declaration expression<sub>opt</sub> ; expression<sub>opt</sub> ) statement
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
The controlling expression of an iteration statement shall have scalar type.
<p><!--para 1 -->
The statement
<pre>
- for ( clause-1 ; expression-2 ; expression-3 ) statement</pre>
+ for ( clause-1 ; expression-2 ; expression-3 ) statement
+</pre>
behaves as follows: The expression expression-2 is the controlling expression that is
evaluated before each execution of the loop body. The expression expression-3 is
evaluated as a void expression after each execution of the loop body. If clause-1 is a
goto identifier ;
continue ;
break ;
- return expression<sub>opt</sub> ;</pre>
+ return expression<sub>opt</sub> ;
+</pre>
}
// handle other operations
/* ... */
- }</pre>
+ }
+</pre>
</ol>
<p><!--para 4 -->
EXAMPLE 2 A goto statement is not allowed to jump past any declarations of objects with variably
lab4:
a[j] = <a href="#6.6">6.6</a>;
}
- goto lab4; // invalid: going INTO scope of VLA.</pre>
+ goto lab4; // invalid: going INTO scope of VLA.
+</pre>
<h5><a name="6.8.6.2" href="#6.8.6.2">6.8.6.2 The continue statement</a></h5>
<pre>
/* ... */ /* ... */ /* ... */
continue; continue; continue;
- /* ... */ /* ... */ /* ... */</pre>
+ /* ... */ /* ... */ /* ... */
+</pre>
contin: ; contin: ; contin: ;
} } while (/* ... */); }
unless the continue statement shown is in an enclosed iteration statement (in which
return g.u1.f2;
}
/* ... */
- g.u2.f3 = f();</pre>
+ g.u2.f3 = f();
+</pre>
there is no undefined behavior, although there would be if the assignment were done directly (without using
a function call to fetch the value).
translation-unit external-declaration
external-declaration:
function-definition
- declaration</pre>
+ declaration
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
The storage-class specifiers auto and register shall not appear in the declaration
declaration-specifiers declarator declaration-list<sub>opt</sub> compound-statement
declaration-list:
declaration
- declaration-list declaration</pre>
+ declaration-list declaration
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
The identifier declared in a function definition (which is the name of the function) shall
extern int max(int a, int b)
{
return a > b ? a : b;
- }</pre>
+ }
+</pre>
extern is the storage-class specifier and int is the type specifier; max(int a, int b) is the
function declarator; and
<pre>
- { return a > b ? a : b; }</pre>
+ { return a > b ? a : b; }
+</pre>
is the function body. The following similar definition uses the identifier-list form for the parameter
declarations:
int a, b;
{
return a > b ? a : b;
- }</pre>
+ }
+</pre>
Here int a, b; is the declaration list for the parameters. The difference between these two definitions is
that the first form acts as a prototype declaration that forces conversion of the arguments of subsequent calls
to the function, whereas the second form does not.
<pre>
int f(void);
/* ... */
- g(f);</pre>
+ g(f);
+</pre>
Then the definition of g might read
<pre>
void g(int (*funcp)(void))
{
/* ... */
(*funcp)(); /* or funcp(); ... */
- }</pre>
+ }
+</pre>
or, equivalently,
<pre>
void g(int func(void))
{
/* ... */
func(); /* or (*func)(); ... */
- }</pre>
+ }
+</pre>
<h6>footnotes</h6>
F *e(void) { /* ... */ } // e returns a pointer to a function
F *((e))(void) { /* ... */ } // same: parentheses irrelevant
int (*fp)(void); // fp points to a function that has type F
- F *Fp; // Fp points to a function that has type F</pre>
+ F *Fp; // Fp points to a function that has type F
+</pre>
</small>
<p><small><a name="note163" href="#note163">163)</a> See ''future language directions'' (<a href="#6.11.7">6.11.7</a>).
</small>
extern int i2; // refers to previous, whose linkage is internal
extern int i3; // refers to previous, whose linkage is external
extern int i4; // refers to previous, whose linkage is external
- extern int i5; // refers to previous, whose linkage is internal</pre>
+ extern int i5; // refers to previous, whose linkage is internal
+</pre>
<p><!--para 5 -->
EXAMPLE 2 If at the end of the translation unit containing
<pre>
- int i[];</pre>
+ int i[];
+</pre>
the array i still has incomplete type, the implicit initializer causes it to have one element, which is set to
zero on program startup.
<!--page 177 -->
preprocessing-token
pp-tokens preprocessing-token
new-line:
- the new-line character</pre>
+ the new-line character
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
A preprocessing directive consists of a sequence of preprocessing tokens that satisfies the
EXAMPLE In:
<pre>
#define EMPTY
- EMPTY # include <file.h></pre>
+ EMPTY # include <file.h>
+</pre>
the sequence of preprocessing tokens on the second line is not a preprocessing directive, because it does not
begin with a # at the start of translation phase 4, even though it will do so after the macro EMPTY has been
replaced.
except that: identifiers (including those lexically identical to keywords) are interpreted as *
described below;<sup><a href="#note166"><b>166)</b></a></sup> and it may contain unary operator expressions of the form
<pre>
- defined identifier</pre>
+ defined identifier
+</pre>
or
<pre>
- defined ( identifier )</pre>
+ defined ( identifier )
+</pre>
which evaluate to 1 if the identifier is currently defined as a macro name (that is, if it is
Preprocessing directives of the forms
<pre>
# if constant-expression new-line group<sub>opt</sub>
- # elif constant-expression new-line group<sub>opt</sub></pre>
+ # elif constant-expression new-line group<sub>opt</sub>
+</pre>
check whether the controlling constant expression evaluates to nonzero.
<p><!--para 4 -->
Prior to evaluation, macro invocations in the list of preprocessing tokens that will become
Preprocessing directives of the forms
<pre>
# ifdef identifier new-line group<sub>opt</sub>
- # ifndef identifier new-line group<sub>opt</sub></pre>
+ # ifndef identifier new-line group<sub>opt</sub>
+</pre>
check whether the identifier is or is not currently defined as a macro name. Their
conditions are equivalent to #if defined identifier and #if !defined identifier
respectively.
<p><!--para 2 -->
A preprocessing directive of the form
<pre>
- # include <h-char-sequence> new-line</pre>
+ # include <h-char-sequence> new-line
+</pre>
searches a sequence of implementation-defined places for a header identified uniquely by
the specified sequence between the < and > delimiters, and causes the replacement of that
directive by the entire contents of the header. How the places are specified or the header
<p><!--para 3 -->
A preprocessing directive of the form
<pre>
- # include "q-char-sequence" new-line</pre>
+ # include "q-char-sequence" new-line
+</pre>
causes the replacement of that directive by the entire contents of the source file identified
by the specified sequence between the " delimiters. The named source file is searched
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
<pre>
- # include <h-char-sequence> new-line</pre>
+ # include <h-char-sequence> new-line
+</pre>
with the identical contained sequence (including > characters, if any) from the original
directive.
<p><!--para 4 -->
A preprocessing directive of the form
<pre>
- # include pp-tokens new-line</pre>
+ # include pp-tokens new-line
+</pre>
(that does not match one of the two previous forms) is permitted. The preprocessing
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
EXAMPLE 1 The most common uses of #include preprocessing directives are as in the following:
<pre>
#include <a href="#7.21"><stdio.h></a>
- #include "myprog.h"</pre>
+ #include "myprog.h"
+</pre>
#else
#define INCFILE "versN.h"
#endif
- #include INCFILE</pre>
+ #include INCFILE
+</pre>
<p><b> Forward references</b>: macro replacement (<a href="#6.10.3">6.10.3</a>).
<p><!--para 9 -->
A preprocessing directive of the form
<pre>
- # define identifier replacement-list new-line</pre>
+ # define identifier replacement-list new-line
+</pre>
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
<pre>
# define identifier lparen identifier-list<sub>opt</sub> ) replacement-list new-line
# define identifier lparen ... ) replacement-list new-line
- # define identifier lparen identifier-list , ... ) replacement-list new-line</pre>
+ # define identifier lparen identifier-list , ... ) replacement-list new-line
+</pre>
defines a function-like macro with parameters, whose use is similar syntactically to a
function call. The parameters are specified by the optional list of identifiers, whose scope
extends from their declaration in the identifier list until the new-line character that
#define in_between(a) mkstr(a)
#define join(c, d) in_between(c hash_hash d)
char p[] = join(x, y); // equivalent to
- // char p[] = "x ## y";</pre>
+ // char p[] = "x ## y";
+</pre>
The expansion produces, at various stages:
<pre>
join(x, y)
in_between(x hash_hash y)
in_between(x ## y)
mkstr(x ## y)
- "x ## y"</pre>
+ "x ## y"
+</pre>
In other words, expanding hash_hash produces a new token, consisting of two adjacent sharp signs, but
this new token is not the ## operator.
<p><!--para 2 -->
A preprocessing directive of the form
<pre>
- # undef identifier new-line</pre>
+ # undef identifier new-line
+</pre>
causes the specified identifier no longer to be defined as a macro name. It is ignored if
the specified identifier is not currently defined as a macro name.
<p><!--para 3 -->
EXAMPLE 1 The simplest use of this facility is to define a ''manifest constant'', as in
<pre>
#define TABSIZE 100
- int table[TABSIZE];</pre>
+ int table[TABSIZE];
+</pre>
<p><!--para 4 -->
EXAMPLE 2 The following defines a function-like macro whose value is the maximum of its arguments.
arguments a second time (including side effects) and generating more code than a function if invoked
several times. It also cannot have its address taken, as it has none.
<pre>
- #define max(a, b) ((a) > (b) ? (a) : (b))</pre>
+ #define max(a, b) ((a) > (b) ? (a) : (b))
+</pre>
The parentheses ensure that the arguments and the resulting expression are bound properly.
<!--page 188 -->
<p><!--para 5 -->
g(x+(3,4)-w) | h 5) & m
(f)^m(m);
p() i[q()] = { q(1), r(2,3), r(4,), r(,5), r(,) };
- char c[2][6] = { str(hello), str() };</pre>
+ char c[2][6] = { str(hello), str() };
+</pre>
results in
<pre>
f(2 * (y+1)) + f(2 * (f(2 * (z[0])))) % f(2 * (0)) + t(1);
f(2 * (2+(3,4)-0,1)) | f(2 * (~ 5)) & f(2 * (0,1))^m(0,1);
int i[] = { 1, 23, 4, 5, };
- char c[2][6] = { "hello", "" };</pre>
+ char c[2][6] = { "hello", "" };
+</pre>
<p><!--para 6 -->
EXAMPLE 4 To illustrate the rules for creating character string literals and concatenating tokens, the
== 0) str(: @\n), s);
#include xstr(INCFILE(2).h)
glue(HIGH, LOW);
- xglue(HIGH, LOW)</pre>
+ xglue(HIGH, LOW)
+</pre>
results in
<!--page 189 -->
<pre>
s);
#include "vers2.h" (after macro replacement, before file access)
"hello";
- "hello" ", world"</pre>
+ "hello" ", world"
+</pre>
or, after concatenation of the character string literals,
<pre>
printf("x1= %d, x2= %s", x1, x2);
s);
#include "vers2.h" (after macro replacement, before file access)
"hello";
- "hello, world"</pre>
+ "hello, world"
+</pre>
Space around the # and ## tokens in the macro definition is optional.
<p><!--para 7 -->
<pre>
#define t(x,y,z) x ## y ## z
int j[] = { t(1,2,3), t(,4,5), t(6,,7), t(8,9,),
- t(10,,), t(,11,), t(,,12), t(,,) };</pre>
+ t(10,,), t(,11,), t(,,12), t(,,) };
+</pre>
results in
<pre>
int j[] = { 123, 45, 67, 89,
- 10, 11, 12, };</pre>
+ 10, 11, 12, };
+</pre>
<p><!--para 8 -->
EXAMPLE 6 To demonstrate the redefinition rules, the following sequence is valid.
#define FUNC_LIKE(a) ( a )
#define FUNC_LIKE( a )( /* note the white space */ \
a /* other stuff on this line
- */ )</pre>
+ */ )
+</pre>
But the following redefinitions are invalid:
<pre>
#define OBJ_LIKE (0) // different token sequence
#define OBJ_LIKE (1 - 1) // different white space
#define FUNC_LIKE(b) ( a ) // different parameter usage
- #define FUNC_LIKE(b) ( b ) // different parameter spelling</pre>
+ #define FUNC_LIKE(b) ( b ) // different parameter spelling
+</pre>
<p><!--para 9 -->
EXAMPLE 7 Finally, to show the variable argument list macro facilities:
debug("Flag");
debug("X = %d\n", x);
showlist(The first, second, and third items.);
- report(x>y, "x is %d but y is %d", x, y);</pre>
+ report(x>y, "x is %d but y is %d", x, y);
+</pre>
results in
<pre>
fprintf(stderr, "Flag" );
fprintf(stderr, "X = %d\n", x );
puts( "The first, second, and third items." );
((x>y)?puts("x>y"):
- printf("x is %d but y is %d", x, y));</pre>
+ printf("x is %d but y is %d", x, y));
+</pre>
<h4><a name="6.10.4" href="#6.10.4">6.10.4 Line control</a></h4>
<p><!--para 3 -->
A preprocessing directive of the form
<pre>
- # line digit-sequence new-line</pre>
+ # line digit-sequence new-line
+</pre>
causes the implementation to behave as if the following sequence of source lines begins
with a source line that has a line number as specified by the digit sequence (interpreted as
a decimal integer). The digit sequence shall not specify zero, nor a number greater than
<p><!--para 4 -->
A preprocessing directive of the form
<pre>
- # line digit-sequence "s-char-sequenceopt" new-line</pre>
+ # line digit-sequence "s-char-sequenceopt" new-line
+</pre>
sets the presumed line number similarly and changes the presumed name of the source
file to be the contents of the character string literal.
<p><!--para 5 -->
A preprocessing directive of the form
<pre>
- # line pp-tokens new-line</pre>
+ # line pp-tokens new-line
+</pre>
(that does not match one of the two previous forms) is permitted. The preprocessing
tokens after line on 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
<p><!--para 1 -->
A preprocessing directive of the form
<pre>
- # error pp-tokens<sub>opt</sub> new-line</pre>
+ # error pp-tokens<sub>opt</sub> new-line
+</pre>
causes the implementation to produce a diagnostic message that includes the specified
sequence of preprocessing tokens.
<p><!--para 1 -->
A preprocessing directive of the form
<pre>
- # pragma pp-tokens<sub>opt</sub> new-line</pre>
+ # pragma pp-tokens<sub>opt</sub> new-line
+</pre>
where the preprocessing token STDC does not immediately follow pragma in the
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
#pragma STDC FENV_ACCESS on-off-switch
#pragma STDC CX_LIMITED_RANGE on-off-switch
on-off-switch: one of
- ON OFF DEFAULT</pre>
+ ON OFF DEFAULT
+</pre>
<p><b> Forward references</b>: the FP_CONTRACT pragma (<a href="#7.12.2">7.12.2</a>), the FENV_ACCESS pragma
(<a href="#7.6.1">7.6.1</a>), the CX_LIMITED_RANGE pragma (<a href="#7.3.4">7.3.4</a>).
<p><!--para 1 -->
A preprocessing directive of the form
<pre>
- # new-line</pre>
+ # new-line
+</pre>
has no effect.
<h4><a name="6.10.8" href="#6.10.8">6.10.8 Predefined macro names</a></h4>
months are the same as those generated by the asctime function, and the
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.</pre>
+ shall be supplied.
+</pre>
__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
<pre>
- source line (an integer constant).<sup><a href="#note177"><b>177)</b></a></sup></pre>
+ source line (an integer constant).<sup><a href="#note177"><b>177)</b></a></sup>
+</pre>
__STDC__ The integer constant 1, intended to indicate a conforming implementation.
__STDC_HOSTED__ The integer constant 1 if the implementation is a hosted
<pre>
- implementation or the integer constant 0 if it is not.</pre>
+ implementation or the integer constant 0 if it is not.
+</pre>
<pre>
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
- implementation-defined valid time shall be supplied.</pre>
+ implementation-defined valid time shall be supplied.
+</pre>
<p><b> Forward references</b>: the asctime function (<a href="#7.26.3.1">7.26.3.1</a>).
<h6>footnotes</h6>
consists of all the characters that are defined by ISO/IEC 10646, along with
all amendments and technical corrigenda, as of the specified year and
month. If some other encoding is used, the macro shall not be defined and
- the actual encoding used is implementation-defined.</pre>
+ the actual encoding used is implementation-defined.
+</pre>
__STDC_MB_MIGHT_NEQ_WC__ The integer constant 1, intended to indicate that, in
<pre>
the encoding for wchar_t, a member of the basic character set need not
have a code value equal to its value when used as the lone character in an
- integer character constant.</pre>
+ integer character constant.
+</pre>
__STDC_UTF_16__ The integer constant 1, intended to indicate that values of type
<pre>
char16_t are UTF-16 encoded. If some other encoding is used, the
macro shall not be defined and the actual encoding used is implementation-
- defined.</pre>
+ defined.
+</pre>
__STDC_UTF_32__ The integer constant 1, intended to indicate that values of type
<pre>
char32_t are UTF-32 encoded. If some other encoding is used, the
macro shall not be defined and the actual encoding used is implementation-
- defined.</pre>
+ defined.
+</pre>
<p><b> Forward references</b>: common definitions (<a href="#7.19">7.19</a>), unicode utilities (<a href="#7.27">7.27</a>).
The following macro names are conditionally defined by the implementation:
__STDC_ANALYZABLE__ The integer constant 1, intended to indicate conformance to
<pre>
- the specifications in <a href="#L">annex L</a> (Analyzability).</pre>
+ the specifications in <a href="#L">annex L</a> (Analyzability).
+</pre>
__STDC_IEC_559__ The integer constant 1, intended to indicate conformance to the
<pre>
- specifications in <a href="#F">annex F</a> (IEC 60559 floating-point arithmetic).</pre>
+ specifications in <a href="#F">annex F</a> (IEC 60559 floating-point arithmetic).
+</pre>
__STDC_IEC_559_COMPLEX__ The integer constant 1, intended to indicate
<pre>
adherence to the specifications in <a href="#G">annex G</a> (IEC 60559 compatible complex
- arithmetic).</pre>
+ arithmetic).
+</pre>
__STDC_LIB_EXT1__ The integer constant 201ymmL, intended to indicate support
<pre>
- for the extensions defined in <a href="#K">annex K</a> (Bounds-checking interfaces).<sup><a href="#note179"><b>179)</b></a></sup></pre>
+ for the extensions defined in <a href="#K">annex K</a> (Bounds-checking interfaces).<sup><a href="#note179"><b>179)</b></a></sup>
+</pre>
__STDC_NO_COMPLEX__ The integer constant 1, intended to indicate that the
<pre>
implementation does not support complex types or the <a href="#7.3"><complex.h></a>
- header.</pre>
+ header.
+</pre>
__STDC_NO_THREADS__ The integer constant 1, intended to indicate that the
<pre>
implementation does not support atomic types (including the _Atomic
type qualifier and the <a href="#7.17"><stdatomic.h></a> header) or the <a href="#7.25"><threads.h></a>
- header.</pre>
+ header.
+</pre>
__STDC_NO_VLA__ The integer constant 1, intended to indicate that the
<pre>
implementation does not support variable length arrays or variably
- modified types.</pre>
+ modified types.
+</pre>
<p><!--para 2 -->
An implementation that defines __STDC_NO_COMPLEX__ shall not define
__STDC_IEC_559_COMPLEX__.
<p><!--para 1 -->
A unary operator expression of the form:
<pre>
- _Pragma ( string-literal )</pre>
+ _Pragma ( string-literal )
+</pre>
is processed as follows: The string literal is destringized by deleting the L prefix, if
present, deleting the leading and trailing double-quotes, replacing each escape sequence
\" by a double-quote, and replacing each escape sequence \\ by a single backslash. The
<p><!--para 2 -->
EXAMPLE A directive of the form:
<pre>
- #pragma listing on "..\listing.dir"</pre>
+ #pragma listing on "..\listing.dir"
+</pre>
can also be expressed as:
<pre>
- _Pragma ( "listing on \"..\\listing.dir\"" )</pre>
+ _Pragma ( "listing on \"..\\listing.dir\"" )
+</pre>
The latter form is processed in the same way whether it appears literally as shown, or results from macro
replacement, as in:
<!--page 196 -->
<pre>
#define LISTING(x) PRAGMA(listing on #x)
#define PRAGMA(x) _Pragma(#x)
- LISTING ( ..\listing.dir )</pre>
+ LISTING ( ..\listing.dir )
+</pre>
<h3><a name="6.11" href="#6.11">6.11 Future language directions</a></h3>
<a href="#7.5"><errno.h></a> <a href="#7.12"><math.h></a> <a href="#7.19"><stddef.h></a> <a href="#7.26"><time.h></a>
<a href="#7.6"><fenv.h></a> <a href="#7.13"><setjmp.h></a> <a href="#7.20"><stdint.h></a> <a href="#7.27"><uchar.h></a>
<a href="#7.7"><float.h></a> <a href="#7.14"><signal.h></a> <a href="#7.21"><stdio.h></a> <a href="#7.28"><wchar.h></a>
- <a href="#7.8"><inttypes.h></a> <a href="#7.15"><stdalign.h></a> <a href="#7.22"><stdlib.h></a> <a href="#7.29"><wctype.h></a></pre>
+ <a href="#7.8"><inttypes.h></a> <a href="#7.15"><stdalign.h></a> <a href="#7.22"><stdlib.h></a> <a href="#7.29"><wctype.h></a>
+</pre>
<p><!--para 3 -->
If a file with the same name as one of the above < and > delimited sequences, not
provided as part of the implementation, is placed in any of the standard places that are
#include <a href="#7.22"><stdlib.h></a>
const char *str;
/* ... */
- i = atoi(str);</pre>
+ i = atoi(str);
+</pre>
<li> by use of its associated header (assuredly generating a true function reference)
#undef atoi
const char *str;
/* ... */
- i = atoi(str);</pre>
+ i = atoi(str);
+</pre>
or
<pre>
#include <a href="#7.22"><stdlib.h></a>
const char *str;
/* ... */
- i = (atoi)(str);</pre>
+ i = (atoi)(str);
+</pre>
<li> by explicit declaration
<!--page 203 -->
<pre>
extern int atoi(const char *);
const char *str;
/* ... */
- i = atoi(str);</pre>
+ i = atoi(str);
+</pre>
</ul>
<h6>footnotes</h6>
appropriate header could specify
<pre>
- #define abs(x) _BUILTIN_abs(x)</pre>
+ #define abs(x) _BUILTIN_abs(x)
+</pre>
for a compiler whose code generator will accept it.
In this manner, a user desiring to guarantee that a given library function such as abs will be a genuine
function may write
<pre>
- #undef abs</pre>
+ #undef abs
+</pre>
whether the implementation's header provides a macro implementation of abs or a built-in
implementation. The prototype for the function, which precedes and is hidden by any macro
definition, is thereby revealed also.
The header <a href="#7.2"><assert.h></a> defines the assert and static_assert macros and
refers to another macro,
<pre>
- NDEBUG</pre>
+ NDEBUG
+</pre>
which is not defined by <a href="#7.2"><assert.h></a>. If NDEBUG is defined as a macro name at the
point in the source file where <a href="#7.2"><assert.h></a> is included, the assert macro is defined
simply as
<pre>
- #define assert(ignore) ((void)0)</pre>
+ #define assert(ignore) ((void)0)
+</pre>
The assert macro is redefined according to the current state of NDEBUG each time that
<a href="#7.2"><assert.h></a> is included.
<p><!--para 2 -->
<p><!--para 3 -->
The macro
<pre>
- static_assert</pre>
+ static_assert
+</pre>
expands to _Static_assert.
<h4><a name="7.2.1" href="#7.2.1">7.2.1 Program diagnostics</a></h4>
<p><!--para 1 -->
<pre>
#include <a href="#7.2"><assert.h></a>
- void assert(scalar expression);</pre>
+ void assert(scalar expression);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The assert macro puts diagnostic tests into programs; it expands to a void expression.
<p><!--para 4 -->
The macro
<pre>
- complex</pre>
+ complex
+</pre>
expands to _Complex; the macro
<pre>
- _Complex_I</pre>
+ _Complex_I
+</pre>
expands to a constant expression of type const float _Complex, with the value of
the imaginary unit.<sup><a href="#note193"><b>193)</b></a></sup>
<p><!--para 5 -->
The macros
<pre>
- imaginary</pre>
+ imaginary
+</pre>
and
<pre>
- _Imaginary_I</pre>
+ _Imaginary_I
+</pre>
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.
<p><!--para 6 -->
The macro
<pre>
- I</pre>
+ I
+</pre>
expands to either _Imaginary_I or _Complex_I. If _Imaginary_I is not
defined, I shall expand to _Complex_I.
<p><!--para 7 -->
<p><!--para 1 -->
<pre>
#include <a href="#7.3"><complex.h></a>
- #pragma STDC CX_LIMITED_RANGE on-off-switch</pre>
+ #pragma STDC CX_LIMITED_RANGE on-off-switch
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The usual mathematical formulas for complex multiply, divide, and absolute value are
(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
- -----</pre>
+ -----
+</pre>
where the programmer can determine they are safe.
</small>
#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);</pre>
+ long double complex cacosl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cacos functions compute the complex arc cosine of z, with branch cuts outside the
#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);</pre>
+ long double complex casinl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The casin functions compute the complex arc sine of z, with branch cuts outside the
#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);</pre>
+ long double complex catanl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The catan functions compute the complex arc tangent of z, with branch cuts outside the
#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);</pre>
+ long double complex ccosl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ccos functions compute the complex cosine of z.
#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);</pre>
+ long double complex csinl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The csin functions compute the complex sine of z.
#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);</pre>
+ long double complex ctanl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ctan functions compute the complex tangent of z.
#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);</pre>
+ long double complex cacoshl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cacosh functions compute the complex arc hyperbolic cosine of z, with a branch
#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);</pre>
+ long double complex casinhl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The casinh functions compute the complex arc hyperbolic sine of z, with branch cuts
#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);</pre>
+ long double complex catanhl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The catanh functions compute the complex arc hyperbolic tangent of z, with branch
#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);</pre>
+ long double complex ccoshl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ccosh functions compute the complex hyperbolic cosine of z.
#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);</pre>
+ long double complex csinhl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The csinh functions compute the complex hyperbolic sine of z.
#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);</pre>
+ long double complex ctanhl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ctanh functions compute the complex hyperbolic tangent of z.
#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);</pre>
+ long double complex cexpl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cexp functions compute the complex base-e exponential of z.
#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);</pre>
+ long double complex clogl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The clog functions compute the complex natural (base-e) logarithm of z, with a branch
#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);</pre>
+ long double cabsl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cabs functions compute the complex absolute value (also called norm, modulus, or
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);</pre>
+ long double complex y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cpow functions compute the complex power function xy , with a branch cut for the
#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);</pre>
+ long double complex csqrtl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The csqrt functions compute the complex square root of z, with a branch cut along the
#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);</pre>
+ long double cargl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The carg functions compute the argument (also called phase angle) of z, with a branch
#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);</pre>
+ long double cimagl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cimag functions compute the imaginary part of z.<sup><a href="#note196"><b>196)</b></a></sup>
#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);</pre>
+ long double complex CMPLXL(long double x, long double y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The CMPLX macros expand to an expression of the specified complex type, with the real
#define CMPLXF(x, y) ((float complex)((float)(x) + \
_Imaginary_I * (float)(y)))
#define CMPLXL(x, y) ((long double complex)((long double)(x) + \
- _Imaginary_I * (long double)(y)))</pre>
+ _Imaginary_I * (long double)(y)))
+</pre>
#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);</pre>
+ long double complex conjl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The conj functions compute the complex conjugate of z, by reversing the sign of its
#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);</pre>
+ long double complex cprojl(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cproj functions compute a projection of z onto the Riemann sphere: z projects to
project to positive infinity on the real axis. If z has an infinite part, then cproj(z) is
equivalent to
<pre>
- INFINITY + I * copysign(0.0, cimag(z))</pre>
+ INFINITY + I * copysign(0.0, cimag(z))
+</pre>
<h6>Returns</h6>
<p><!--para 3 -->
The cproj functions return the value of the projection onto the Riemann sphere.
#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);</pre>
+ long double creall(long double complex z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The creal functions compute the real part of z.<sup><a href="#note197"><b>197)</b></a></sup>
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int isalnum(int c);</pre>
+ int isalnum(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isalnum function tests for any character for which isalpha or isdigit is true.
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int isalpha(int c);</pre>
+ int isalpha(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isalpha function tests for any character for which isupper or islower is true,
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int isblank(int c);</pre>
+ int isblank(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isblank function tests for any character that is a standard blank character or is one
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int iscntrl(int c);</pre>
+ int iscntrl(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The iscntrl function tests for any control character.
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int isdigit(int c);</pre>
+ int isdigit(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isdigit function tests for any decimal-digit character (as defined in <a href="#5.2.1">5.2.1</a>).
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int isgraph(int c);</pre>
+ int isgraph(int c);
+</pre>
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int islower(int c);</pre>
+ int islower(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The islower function tests for any character that is a lowercase letter or is one of a
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int isprint(int c);</pre>
+ int isprint(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isprint function tests for any printing character including space (' ').
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int ispunct(int c);</pre>
+ int ispunct(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ispunct function tests for any printing character that is one of a locale-specific set
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int isspace(int c);</pre>
+ int isspace(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isspace function tests for any character that is a standard white-space character or
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int isupper(int c);</pre>
+ int isupper(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isupper function tests for any character that is an uppercase letter or is one of a
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int isxdigit(int c);</pre>
+ int isxdigit(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isxdigit function tests for any hexadecimal-digit character (as defined in <a href="#6.4.4.1">6.4.4.1</a>).
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int tolower(int c);</pre>
+ int tolower(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The tolower function converts an uppercase letter to a corresponding lowercase letter.
<p><!--para 1 -->
<pre>
#include <a href="#7.4"><ctype.h></a>
- int toupper(int c);</pre>
+ int toupper(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The toupper function converts a lowercase letter to a corresponding uppercase letter.
<pre>
EDOM
EILSEQ
- ERANGE</pre>
+ ERANGE
+</pre>
which expand to integer constant expressions with type int, distinct positive values, and
which are suitable for use in #if preprocessing directives; and
<pre>
- errno</pre>
+ errno
+</pre>
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
<p><!--para 4 -->
The type
<pre>
- fenv_t</pre>
+ fenv_t
+</pre>
represents the entire floating-point environment.
<p><!--para 5 -->
The type
<pre>
- fexcept_t</pre>
+ fexcept_t
+</pre>
represents the floating-point status flags collectively, including any status the
implementation associates with the flags.
FE_INEXACT
FE_INVALID
FE_OVERFLOW
- FE_UNDERFLOW</pre>
+ FE_UNDERFLOW
+</pre>
is defined if and only if the implementation supports the floating-point exception by
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
<p><!--para 7 -->
The macro
<pre>
- FE_ALL_EXCEPT</pre>
+ FE_ALL_EXCEPT
+</pre>
is simply the bitwise OR of all floating-point exception macros defined by the
implementation. If no such macros are defined, FE_ALL_EXCEPT shall be defined as 0.
<p><!--para 8 -->
FE_DOWNWARD
FE_TONEAREST
FE_TOWARDZERO
- FE_UPWARD</pre>
+ FE_UPWARD
+</pre>
is defined if and only if the implementation supports getting and setting the represented
rounding direction by means of the fegetround and fesetround functions.
Additional implementation-defined rounding directions, with macro definitions beginning
<!--page 225 -->
<pre>
- FE_DFL_ENV</pre>
+ FE_DFL_ENV
+</pre>
represents the default floating-point environment -- the one installed at program startup
<ul>
<li> and has type ''pointer to const-qualified fenv_t''. It can be used as an argument to
<p><!--para 1 -->
<pre>
#include <a href="#7.6"><fenv.h></a>
- #pragma STDC FENV_ACCESS on-off-switch</pre>
+ #pragma STDC FENV_ACCESS on-off-switch
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The FENV_ACCESS pragma provides a means to inform the implementation when a
g(x + 1);
h(x + 1);
/* ... */
- }</pre>
+ }
+</pre>
<p><!--para 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
<p><!--para 1 -->
<pre>
#include <a href="#7.6"><fenv.h></a>
- int feclearexcept(int excepts);</pre>
+ int feclearexcept(int excepts);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The feclearexcept function attempts to clear the supported floating-point exceptions
<pre>
#include <a href="#7.6"><fenv.h></a>
int fegetexceptflag(fexcept_t *flagp,
- int excepts);</pre>
+ int excepts);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fegetexceptflag function attempts to store an implementation-defined
<p><!--para 1 -->
<pre>
#include <a href="#7.6"><fenv.h></a>
- int feraiseexcept(int excepts);</pre>
+ int feraiseexcept(int excepts);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The feraiseexcept function attempts to raise the supported floating-point exceptions
<pre>
#include <a href="#7.6"><fenv.h></a>
int fesetexceptflag(const fexcept_t *flagp,
- int excepts);</pre>
+ int excepts);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fesetexceptflag function attempts to set the floating-point status flags
<p><!--para 1 -->
<pre>
#include <a href="#7.6"><fenv.h></a>
- int fetestexcept(int excepts);</pre>
+ int fetestexcept(int excepts);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fetestexcept function determines which of a specified subset of the floating-
if (set_excepts & FE_INVALID) f();
if (set_excepts & FE_OVERFLOW) g();
/* ... */
- }</pre>
+ }
+</pre>
<h6>footnotes</h6>
<p><!--para 1 -->
<pre>
#include <a href="#7.6"><fenv.h></a>
- int fegetround(void);</pre>
+ int fegetround(void);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fegetround function gets the current rounding direction.
<p><!--para 1 -->
<pre>
#include <a href="#7.6"><fenv.h></a>
- int fesetround(int round);</pre>
+ int fesetround(int round);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fesetround function establishes the rounding direction represented by its
/* ... */
fesetround(save_round);
/* ... */
- }</pre>
+ }
+</pre>
<h4><a name="7.6.4" href="#7.6.4">7.6.4 Environment</a></h4>
<p><!--para 1 -->
<pre>
#include <a href="#7.6"><fenv.h></a>
- int fegetenv(fenv_t *envp);</pre>
+ int fegetenv(fenv_t *envp);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fegetenv function attempts to store the current floating-point environment in the
<p><!--para 1 -->
<pre>
#include <a href="#7.6"><fenv.h></a>
- int feholdexcept(fenv_t *envp);</pre>
+ int feholdexcept(fenv_t *envp);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The feholdexcept function saves the current floating-point environment in the object
<p><!--para 1 -->
<pre>
#include <a href="#7.6"><fenv.h></a>
- int fesetenv(const fenv_t *envp);</pre>
+ int fesetenv(const fenv_t *envp);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fesetenv function attempts to establish the floating-point environment represented
<p><!--para 1 -->
<pre>
#include <a href="#7.6"><fenv.h></a>
- int feupdateenv(const fenv_t *envp);</pre>
+ int feupdateenv(const fenv_t *envp);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The feupdateenv function attempts to save the currently raised floating-point
if (feupdateenv(&save_env))
return /* indication of an environmental problem */;
return result;
- }</pre>
+ }
+</pre>
<h3><a name="7.7" href="#7.7">7.7 Characteristics of floating types <float.h></a></h3>
<p><!--para 1 -->
It declares functions for manipulating greatest-width integers and converting numeric
character strings to greatest-width integers, and it declares the type
<pre>
- imaxdiv_t</pre>
+ imaxdiv_t
+</pre>
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.<sup><a href="#note216"><b>216)</b></a></sup>
The fprintf macros for signed integers are:
<pre>
PRIdN PRIdLEASTN PRIdFASTN PRIdMAX PRIdPTR
- PRIiN PRIiLEASTN PRIiFASTN PRIiMAX PRIiPTR</pre>
+ PRIiN PRIiLEASTN PRIiFASTN PRIiMAX PRIiPTR
+</pre>
<p><!--para 3 -->
The fprintf macros for unsigned integers are:
<pre>
PRIoN PRIoLEASTN PRIoFASTN PRIoMAX PRIoPTR
PRIuN PRIuLEASTN PRIuFASTN PRIuMAX PRIuPTR
PRIxN PRIxLEASTN PRIxFASTN PRIxMAX PRIxPTR
- PRIXN PRIXLEASTN PRIXFASTN PRIXMAX PRIXPTR</pre>
+ PRIXN PRIXLEASTN PRIXFASTN PRIXMAX PRIXPTR
+</pre>
<p><!--para 4 -->
The fscanf macros for signed integers are:
<!--page 235 -->
<pre>
SCNdN SCNdLEASTN SCNdFASTN SCNdMAX SCNdPTR
- SCNiN SCNiLEASTN SCNiFASTN SCNiMAX SCNiPTR</pre>
+ SCNiN SCNiLEASTN SCNiFASTN SCNiMAX SCNiPTR
+</pre>
<p><!--para 5 -->
The fscanf macros for unsigned integers are:
<pre>
SCNoN SCNoLEASTN SCNoFASTN SCNoMAX SCNoPTR
SCNuN SCNuLEASTN SCNuFASTN SCNuMAX SCNuPTR
- SCNxN SCNxLEASTN SCNxFASTN SCNxMAX SCNxPTR</pre>
+ SCNxN SCNxLEASTN SCNxFASTN SCNxMAX SCNxPTR
+</pre>
<p><!--para 6 -->
For each type that the implementation provides in <a href="#7.20"><stdint.h></a>, the corresponding
fprintf macros shall be defined and the corresponding fscanf macros shall be
wprintf(L"The largest integer value is %020"
PRIxMAX "\n", i);
return 0;
- }</pre>
+ }
+</pre>
<h6>footnotes</h6>
<p><!--para 1 -->
<pre>
#include <a href="#7.8"><inttypes.h></a>
- intmax_t imaxabs(intmax_t j);</pre>
+ intmax_t imaxabs(intmax_t j);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The imaxabs function computes the absolute value of an integer j. If the result cannot
<p><!--para 1 -->
<pre>
#include <a href="#7.8"><inttypes.h></a>
- imaxdiv_t imaxdiv(intmax_t numer, intmax_t denom);</pre>
+ imaxdiv_t imaxdiv(intmax_t numer, intmax_t denom);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The imaxdiv function computes numer / denom and numer % denom in a single
intmax_t strtoimax(const char * restrict nptr,
char ** restrict endptr, int base);
uintmax_t strtoumax(const char * restrict nptr,
- char ** restrict endptr, int base);</pre>
+ char ** restrict endptr, int base);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strtoimax and strtoumax functions are equivalent to the strtol, strtoll,
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);</pre>
+ wchar_t ** restrict endptr, int base);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcstoimax and wcstoumax functions are equivalent to the wcstol, wcstoll,
or ||
or_eq |=
xor ^
- xor_eq ^=</pre>
+ xor_eq ^=
+</pre>
<h3><a name="7.10" href="#7.10">7.10 Sizes of integer types <limits.h></a></h3>
<p><!--para 1 -->
<p><!--para 2 -->
The type is
<pre>
- struct lconv</pre>
+ struct lconv
+</pre>
which contains members related to the formatting of numeric values. The structure shall
contain at least the following members, in any order. The semantics of the members and
their normal ranges are explained in <a href="#7.11.2.1">7.11.2.1</a>. In the "C" locale, the members shall have
char int_p_sep_by_space; // CHAR_MAX
char int_n_sep_by_space; // CHAR_MAX
char int_p_sign_posn; // CHAR_MAX
- char int_n_sign_posn; // CHAR_MAX</pre>
+ char int_n_sign_posn; // CHAR_MAX
+</pre>
<p><!--para 3 -->
The macros defined are NULL (described in <a href="#7.19">7.19</a>); and
<pre>
LC_CTYPE
LC_MONETARY
LC_NUMERIC
- LC_TIME</pre>
+ LC_TIME
+</pre>
which expand to integer constant expressions with distinct values, suitable for use as 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
<p><!--para 1 -->
<pre>
#include <a href="#7.11"><locale.h></a>
- char *setlocale(int category, const char *locale);</pre>
+ char *setlocale(int category, const char *locale);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The setlocale function selects the appropriate portion of the program's locale as
<p><!--para 4 -->
At program startup, the equivalent of
<pre>
- setlocale(LC_ALL, "C");</pre>
+ setlocale(LC_ALL, "C");
+</pre>
is executed.
<p><!--para 5 -->
A call to the setlocale function may introduce a data race with other calls to the
<p><!--para 1 -->
<pre>
#include <a href="#7.11"><locale.h></a>
- struct lconv *localeconv(void);</pre>
+ struct lconv *localeconv(void);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The localeconv function sets the components of an object with type struct lconv
available in the current locale. The members include the following:
char *decimal_point
<pre>
- The decimal-point character used to format nonmonetary quantities.</pre>
+ The decimal-point character used to format nonmonetary quantities.
+</pre>
char *thousands_sep
<pre>
The character used to separate groups of digits before the decimal-point
- character in formatted nonmonetary quantities.</pre>
+ character in formatted nonmonetary quantities.
+</pre>
char *grouping
<pre>
A string whose elements indicate the size of each group of digits in
- formatted nonmonetary quantities.</pre>
+ formatted nonmonetary quantities.
+</pre>
char *mon_decimal_point
<pre>
- The decimal-point used to format monetary quantities.</pre>
+ The decimal-point used to format monetary quantities.
+</pre>
char *mon_thousands_sep
<pre>
The separator for groups of digits before the decimal-point in formatted
- monetary quantities.</pre>
+ monetary quantities.
+</pre>
char *mon_grouping
<pre>
A string whose elements indicate the size of each group of digits in
- formatted monetary quantities.</pre>
+ formatted monetary quantities.
+</pre>
char *positive_sign
<pre>
The string used to indicate a nonnegative-valued formatted monetary
- quantity.</pre>
+ quantity.
+</pre>
char *negative_sign
<pre>
- The string used to indicate a negative-valued formatted monetary quantity.</pre>
+ The string used to indicate a negative-valued formatted monetary quantity.
+</pre>
char *currency_symbol
<pre>
- The local currency symbol applicable to the current locale.</pre>
+ The local currency symbol applicable to the current locale.
+</pre>
char frac_digits
<pre>
The number of fractional digits (those after the decimal-point) to be
- displayed in a locally formatted monetary quantity.</pre>
+ displayed in a locally formatted monetary quantity.
+</pre>
char p_cs_precedes
<!--page 244 -->
<pre>
Set to 1 or 0 if the currency_symbol respectively precedes or
- succeeds the value for a nonnegative locally formatted monetary quantity.</pre>
+ succeeds the value for a nonnegative locally formatted monetary quantity.
+</pre>
char n_cs_precedes
<pre>
Set to 1 or 0 if the currency_symbol respectively precedes or
- succeeds the value for a negative locally formatted monetary quantity.</pre>
+ succeeds the value for a negative locally formatted monetary quantity.
+</pre>
char p_sep_by_space
<pre>
Set to a value indicating the separation of the currency_symbol, the
sign string, and the value for a nonnegative locally formatted monetary
- quantity.</pre>
+ quantity.
+</pre>
char n_sep_by_space
<pre>
Set to a value indicating the separation of the currency_symbol, the
sign string, and the value for a negative locally formatted monetary
- quantity.</pre>
+ quantity.
+</pre>
char p_sign_posn
<pre>
Set to a value indicating the positioning of the positive_sign for a
- nonnegative locally formatted monetary quantity.</pre>
+ nonnegative locally formatted monetary quantity.
+</pre>
char n_sign_posn
<pre>
Set to a value indicating the positioning of the negative_sign for a
- negative locally formatted monetary quantity.</pre>
+ negative locally formatted monetary quantity.
+</pre>
char *int_curr_symbol
<pre>
The international currency symbol applicable to the current locale. The
first three characters contain the alphabetic international currency symbol
in accordance with those specified in ISO 4217. The fourth character
(immediately preceding the null character) is the character used to separate
- the international currency symbol from the monetary quantity.</pre>
+ the international currency symbol from the monetary quantity.
+</pre>
char int_frac_digits
<pre>
The number of fractional digits (those after the decimal-point) to be
- displayed in an internationally formatted monetary quantity.</pre>
+ displayed in an internationally formatted monetary quantity.
+</pre>
char int_p_cs_precedes
<pre>
Set to 1 or 0 if the int_curr_symbol respectively precedes or
succeeds the value for a nonnegative internationally formatted monetary
- quantity.</pre>
+ quantity.
+</pre>
char int_n_cs_precedes
<pre>
Set to 1 or 0 if the int_curr_symbol respectively precedes or
succeeds the value for a negative internationally formatted monetary
- quantity.</pre>
+ quantity.
+</pre>
char int_p_sep_by_space
<!--page 245 -->
<pre>
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.</pre>
+ monetary quantity.
+</pre>
char int_n_sep_by_space
<pre>
Set to a value indicating the separation of the int_curr_symbol, the
sign string, and the value for a negative internationally formatted monetary
- quantity.</pre>
+ quantity.
+</pre>
char int_p_sign_posn
<pre>
Set to a value indicating the positioning of the positive_sign for a
- nonnegative internationally formatted monetary quantity.</pre>
+ nonnegative internationally formatted monetary quantity.
+</pre>
char int_n_sign_posn
<pre>
Set to a value indicating the positioning of the negative_sign for a
- negative internationally formatted monetary quantity.</pre>
+ negative internationally formatted monetary quantity.
+</pre>
<p><!--para 4 -->
The elements of grouping and mon_grouping are interpreted according to the
following:
CHAR_MAX No further grouping is to be performed.
0 The previous element is to be repeatedly used for the remainder of the
<pre>
- digits.</pre>
+ digits.
+</pre>
other The integer value is the number of digits that compose the current group.
<pre>
The next element is examined to determine the size of the next group of
- digits before the current group.</pre>
+ digits before the current group.
+</pre>
<p><!--para 5 -->
The values of p_sep_by_space, n_sep_by_space, int_p_sep_by_space,
and int_n_sep_by_space are interpreted according to the following:
0 No space separates the currency symbol and value.
1 If the currency symbol and sign string are adjacent, a space separates them from the
<pre>
- value; otherwise, a space separates the currency symbol from the value.</pre>
+ value; otherwise, a space separates the currency symbol from the value.
+</pre>
2 If the currency symbol and sign string are adjacent, a space separates them;
<pre>
- otherwise, a space separates the sign string from the value.</pre>
+ otherwise, a space separates the sign string from the value.
+</pre>
For int_p_sep_by_space and int_n_sep_by_space, the fourth character of
int_curr_symbol is used instead of a space.
<p><!--para 6 -->
EXAMPLE 1 The following table illustrates rules which may well be used by four countries to format
monetary quantities.
<pre>
- Local format International format</pre>
+ Local format International format
+</pre>
Country Positive Negative Positive Negative
For these four countries, the respective values for the monetary members of the structure returned by
localeconv could be:
<pre>
- Country1 Country2 Country3 Country4</pre>
+ Country1 Country2 Country3 Country4
+</pre>
mon_decimal_point "," "" "," "."
mon_thousands_sep "." "." "." ","
EXAMPLE 2 The following table illustrates how the cs_precedes, sep_by_space, and sign_posn members
affect the formatted value.
<pre>
- p_sep_by_space</pre>
+ p_sep_by_space
+</pre>
p_cs_precedes p_sign_posn 0 1 2
1 +1.25$ +1.25 $ + <a href="#1.25">1.25</a>$
2 <a href="#1.25">1.25</a>$+ <a href="#1.25">1.25</a> $+ <a href="#1.25">1.25</a>$ +
3 <a href="#1.25">1.25</a>+$ <a href="#1.25">1.25</a> +$ <a href="#1.25">1.25</a>+ $
- 4 <a href="#1.25">1.25</a>$+ <a href="#1.25">1.25</a> $+ <a href="#1.25">1.25</a>$ +</pre>
+ 4 <a href="#1.25">1.25</a>$+ <a href="#1.25">1.25</a> $+ <a href="#1.25">1.25</a>$ +
+</pre>
<!--page 248 -->
<pre>
1 +$1.25 +$ <a href="#1.25">1.25</a> + $1.25
2 $1.25+ $ <a href="#1.25">1.25</a>+ $1.25 +
3 +$1.25 +$ <a href="#1.25">1.25</a> + $1.25
- 4 $+1.25 $+ <a href="#1.25">1.25</a> $ +1.25</pre>
+ 4 $+1.25 $+ <a href="#1.25">1.25</a> $ +1.25
+</pre>
<h3><a name="7.12" href="#7.12">7.12 Mathematics <math.h></a></h3>
<p><!--para 1 -->
The types
<pre>
float_t
- double_t</pre>
+ double_t
+</pre>
are floating types at least as wide as float and double, respectively, and such that
double_t is at least as wide as float_t. If FLT_EVAL_METHOD equals 0,
float_t and double_t are float and double, respectively; if
<p><!--para 3 -->
The macro
<pre>
- HUGE_VAL</pre>
+ HUGE_VAL
+</pre>
expands to a positive double constant expression, not necessarily representable as a
float. The macros
<pre>
HUGE_VALF
- HUGE_VALL</pre>
+ HUGE_VALL
+</pre>
are respectively float and long double analogs of HUGE_VAL.<sup><a href="#note225"><b>225)</b></a></sup>
<p><!--para 4 -->
The macro
<pre>
- INFINITY</pre>
+ INFINITY
+</pre>
expands to a constant expression of type float representing positive or unsigned
infinity, if available; else to a positive constant of type float that overflows at
<p><!--para 5 -->
The macro
<pre>
- NAN</pre>
+ NAN
+</pre>
is defined if and only if the implementation supports quiet NaNs for the float type. It
expands to a constant expression of type float representing a quiet NaN.
<p><!--para 6 -->
FP_NAN
FP_NORMAL
FP_SUBNORMAL
- FP_ZERO</pre>
+ FP_ZERO
+</pre>
represent the mutually exclusive kinds of floating-point values. They expand to integer
constant expressions with distinct values. Additional implementation-defined floating-
point classifications, with macro definitions beginning with FP_ and an uppercase letter,
<p><!--para 7 -->
The macro
<pre>
- FP_FAST_FMA</pre>
+ FP_FAST_FMA
+</pre>
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.<sup><a href="#note227"><b>227)</b></a></sup> The
macros
<pre>
FP_FAST_FMAF
- FP_FAST_FMAL</pre>
+ FP_FAST_FMAL
+</pre>
are, respectively, float and long double analogs of FP_FAST_FMA. If defined,
these macros expand to the integer constant 1.
<p><!--para 8 -->
The macros
<pre>
FP_ILOGB0
- FP_ILOGBNAN</pre>
+ FP_ILOGBNAN
+</pre>
expand to integer constant expressions whose values are returned by ilogb(x) if x is
zero or NaN, respectively. The value of FP_ILOGB0 shall be either INT_MIN or
-INT_MAX. The value of FP_ILOGBNAN shall be either INT_MAX or INT_MIN.
The macros
<pre>
MATH_ERRNO
- MATH_ERREXCEPT</pre>
+ MATH_ERREXCEPT
+</pre>
expand to the integer constants 1 and 2, respectively; the macro
<pre>
- math_errhandling</pre>
+ math_errhandling
+</pre>
expands to an expression that has type int and the value MATH_ERRNO,
MATH_ERREXCEPT, or the bitwise OR of both. The value of math_errhandling is
constant for the duration of the program. It is unspecified whether
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- #pragma STDC FP_CONTRACT on-off-switch</pre>
+ #pragma STDC FP_CONTRACT on-off-switch
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The FP_CONTRACT pragma can be used to allow (if the state is ''on'') or disallow (if the
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- int fpclassify(real-floating x);</pre>
+ int fpclassify(real-floating x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fpclassify macro classifies its argument value as NaN, infinite, normal,
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- int isfinite(real-floating x);</pre>
+ int isfinite(real-floating x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isfinite macro determines whether its argument has a finite value (zero,
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- int isinf(real-floating x);</pre>
+ int isinf(real-floating x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isinf macro determines whether its argument value is an infinity (positive or
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- int isnan(real-floating x);</pre>
+ int isnan(real-floating x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isnan macro determines whether its argument value is a NaN. First, an argument
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- int isnormal(real-floating x);</pre>
+ int isnormal(real-floating x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isnormal macro determines whether its argument value is normal (neither zero,
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- int signbit(real-floating x);</pre>
+ int signbit(real-floating x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The signbit macro determines whether the sign of its argument value is negative.<sup><a href="#note233"><b>233)</b></a></sup>
#include <a href="#7.12"><math.h></a>
double acos(double x);
float acosf(float x);
- long double acosl(long double x);</pre>
+ long double acosl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The acos functions compute the principal value of the arc cosine of x. A domain error
#include <a href="#7.12"><math.h></a>
double asin(double x);
float asinf(float x);
- long double asinl(long double x);</pre>
+ long double asinl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The asin functions compute the principal value of the arc sine of x. A domain error
#include <a href="#7.12"><math.h></a>
double atan(double x);
float atanf(float x);
- long double atanl(long double x);</pre>
+ long double atanl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The atan functions compute the principal value of the arc tangent of x.
#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);</pre>
+ long double atan2l(long double y, long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The atan2 functions compute the value of the arc tangent of y/x, using the signs of both
#include <a href="#7.12"><math.h></a>
double cos(double x);
float cosf(float x);
- long double cosl(long double x);</pre>
+ long double cosl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cos functions compute the cosine of x (measured in radians).
#include <a href="#7.12"><math.h></a>
double sin(double x);
float sinf(float x);
- long double sinl(long double x);</pre>
+ long double sinl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The sin functions compute the sine of x (measured in radians).
#include <a href="#7.12"><math.h></a>
double tan(double x);
float tanf(float x);
- long double tanl(long double x);</pre>
+ long double tanl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The tan functions return the tangent of x (measured in radians).
#include <a href="#7.12"><math.h></a>
double acosh(double x);
float acoshf(float x);
- long double acoshl(long double x);</pre>
+ long double acoshl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The acosh functions compute the (nonnegative) arc hyperbolic cosine of x. A domain
#include <a href="#7.12"><math.h></a>
double asinh(double x);
float asinhf(float x);
- long double asinhl(long double x);</pre>
+ long double asinhl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The asinh functions compute the arc hyperbolic sine of x.
#include <a href="#7.12"><math.h></a>
double atanh(double x);
float atanhf(float x);
- long double atanhl(long double x);</pre>
+ long double atanhl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The atanh functions compute the arc hyperbolic tangent of x. A domain error occurs
#include <a href="#7.12"><math.h></a>
double cosh(double x);
float coshf(float x);
- long double coshl(long double x);</pre>
+ long double coshl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cosh functions compute the hyperbolic cosine of x. A range error occurs if the
#include <a href="#7.12"><math.h></a>
double sinh(double x);
float sinhf(float x);
- long double sinhl(long double x);</pre>
+ long double sinhl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The sinh functions compute the hyperbolic sine of x. A range error occurs if the
#include <a href="#7.12"><math.h></a>
double tanh(double x);
float tanhf(float x);
- long double tanhl(long double x);</pre>
+ long double tanhl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The tanh functions compute the hyperbolic tangent of x.
#include <a href="#7.12"><math.h></a>
double exp(double x);
float expf(float x);
- long double expl(long double x);</pre>
+ long double expl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The exp functions compute the base-e exponential of x. A range error occurs if the
#include <a href="#7.12"><math.h></a>
double exp2(double x);
float exp2f(float x);
- long double exp2l(long double x);</pre>
+ long double exp2l(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The exp2 functions compute the base-2 exponential of x. A range error occurs if the
#include <a href="#7.12"><math.h></a>
double expm1(double x);
float expm1f(float x);
- long double expm1l(long double x);</pre>
+ long double expm1l(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The expm1 functions compute the base-e exponential of the argument, minus 1. A range
#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);</pre>
+ long double frexpl(long double value, int *exp);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The frexp functions break a floating-point number into a normalized fraction and an
#include <a href="#7.12"><math.h></a>
int ilogb(double x);
int ilogbf(float x);
- int ilogbl(long double x);</pre>
+ int ilogbl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ilogb functions extract the exponent of x as a signed int value. If x is zero they
#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);</pre>
+ long double ldexpl(long double x, int exp);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ldexp functions multiply a floating-point number by an integral power of 2. A
#include <a href="#7.12"><math.h></a>
double log(double x);
float logf(float x);
- long double logl(long double x);</pre>
+ long double logl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The log functions compute the base-e (natural) logarithm of x. A domain error occurs if
#include <a href="#7.12"><math.h></a>
double log10(double x);
float log10f(float x);
- long double log10l(long double x);</pre>
+ long double log10l(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The log10 functions compute the base-10 (common) logarithm of x. A domain error
#include <a href="#7.12"><math.h></a>
double log1p(double x);
float log1pf(float x);
- long double log1pl(long double x);</pre>
+ long double log1pl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The log1p functions compute the base-e (natural) logarithm of 1 plus the argument.<sup><a href="#note235"><b>235)</b></a></sup>
#include <a href="#7.12"><math.h></a>
double log2(double x);
float log2f(float x);
- long double log2l(long double x);</pre>
+ long double log2l(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The log2 functions compute the base-2 logarithm of x. A domain error occurs if the
#include <a href="#7.12"><math.h></a>
double logb(double x);
float logbf(float x);
- long double logbl(long double x);</pre>
+ long double logbl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 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,
<pre>
- 1 <= x x FLT_RADIX-logb(x) < FLT_RADIX</pre>
+ 1 <= x x FLT_RADIX-logb(x) < FLT_RADIX
+</pre>
A domain error or pole error may occur if the argument is zero.
<h6>Returns</h6>
<p><!--para 3 -->
#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);</pre>
+ long double modfl(long double value, long double *iptr);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The modf functions break the argument value into integral and fractional parts, each of
long double scalbnl(long double 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);</pre>
+ long double scalblnl(long double x, long int n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The scalbn and scalbln functions compute x x FLT_RADIXn efficiently, not
#include <a href="#7.12"><math.h></a>
double cbrt(double x);
float cbrtf(float x);
- long double cbrtl(long double x);</pre>
+ long double cbrtl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cbrt functions compute the real cube root of x.
#include <a href="#7.12"><math.h></a>
double fabs(double x);
float fabsf(float x);
- long double fabsl(long double x);</pre>
+ long double fabsl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fabs functions compute the absolute value of a floating-point number x.
#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);</pre>
+ long double hypotl(long double x, long double y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The hypot functions compute the square root of the sum of the squares of x and y,
The hypot functions return (sqrt)x2 + y2 .
<pre>
-
- -----</pre>
+ -----
+</pre>
<h5><a name="7.12.7.4" href="#7.12.7.4">7.12.7.4 The pow functions</a></h5>
<h6>Synopsis</h6>
#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);</pre>
+ long double powl(long double x, long double y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The pow functions compute x raised to the power y. A domain error occurs if x is finite
#include <a href="#7.12"><math.h></a>
double sqrt(double x);
float sqrtf(float x);
- long double sqrtl(long double x);</pre>
+ long double sqrtl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The sqrt functions compute the nonnegative square root of x. A domain error occurs if
The sqrt functions return (sqrt)x.
<pre>
-
- -</pre>
+ -
+</pre>
<h4><a name="7.12.8" href="#7.12.8">7.12.8 Error and gamma functions</a></h4>
#include <a href="#7.12"><math.h></a>
double erf(double x);
float erff(float x);
- long double erfl(long double x);</pre>
+ long double erfl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The erf functions compute the error function of x.
<pre>
2 x
(integral) e-t dt.
- 2</pre>
+ 2
+</pre>
The erf functions return erf x =
<pre>
(sqrt)pi
-
- - 0</pre>
+ - 0
+</pre>
<h5><a name="7.12.8.2" href="#7.12.8.2">7.12.8.2 The erfc functions</a></h5>
#include <a href="#7.12"><math.h></a>
double erfc(double x);
float erfcf(float x);
- long double erfcl(long double x);</pre>
+ long double erfcl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The erfc functions compute the complementary error function of x. A range error
<pre>
2 (inf)
(integral) e-t dt.
- 2</pre>
+ 2
+</pre>
The erfc functions return erfc x = 1 - erf x =
<pre>
(sqrt)pi
-
- - x</pre>
+ - x
+</pre>
<h5><a name="7.12.8.3" href="#7.12.8.3">7.12.8.3 The lgamma functions</a></h5>
#include <a href="#7.12"><math.h></a>
double lgamma(double x);
float lgammaf(float x);
- long double lgammal(long double x);</pre>
+ long double lgammal(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The lgamma functions compute the natural logarithm of the absolute value of gamma of
#include <a href="#7.12"><math.h></a>
double tgamma(double x);
float tgammaf(float x);
- long double tgammal(long double x);</pre>
+ long double tgammal(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The tgamma functions compute the gamma function of x. A domain error or pole error
#include <a href="#7.12"><math.h></a>
double ceil(double x);
float ceilf(float x);
- long double ceill(long double x);</pre>
+ long double ceill(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ceil functions compute the smallest integer value not less than x.
#include <a href="#7.12"><math.h></a>
double floor(double x);
float floorf(float x);
- long double floorl(long double x);</pre>
+ long double floorl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The floor functions compute the largest integer value not greater than x.
#include <a href="#7.12"><math.h></a>
double nearbyint(double x);
float nearbyintf(float x);
- long double nearbyintl(long double x);</pre>
+ long double nearbyintl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The nearbyint functions round their argument to an integer value in floating-point
#include <a href="#7.12"><math.h></a>
double rint(double x);
float rintf(float x);
- long double rintl(long double x);</pre>
+ long double rintl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The rint functions differ from the nearbyint functions (<a href="#7.12.9.3">7.12.9.3</a>) only in that the
long int lrintl(long double x);
long long int llrint(double x);
long long int llrintf(float x);
- long long int llrintl(long double x);</pre>
+ long long int llrintl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The lrint and llrint functions round their argument to the nearest integer value,
#include <a href="#7.12"><math.h></a>
double round(double x);
float roundf(float x);
- long double roundl(long double x);</pre>
+ long double roundl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The round functions round their argument to the nearest integer value in floating-point
long int lroundl(long double x);
long long int llround(double x);
long long int llroundf(float x);
- long long int llroundl(long double x);</pre>
+ long long int llroundl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The lround and llround functions round their argument to the nearest integer value,
#include <a href="#7.12"><math.h></a>
double trunc(double x);
float truncf(float x);
- long double truncl(long double x);</pre>
+ long double truncl(long double x);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The trunc functions round their argument to the integer value, in floating format,
#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);</pre>
+ long double fmodl(long double x, long double y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fmod functions compute the floating-point remainder of x/y.
#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);</pre>
+ long double remainderl(long double x, long double y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The remainder functions compute the remainder x REM y required by IEC 60559.<sup><a href="#note236"><b>236)</b></a></sup>
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);</pre>
+ int *quo);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The remquo functions compute the same remainder as the remainder functions. In
#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);</pre>
+ long double copysignl(long double x, long double y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The copysign functions produce a value with the magnitude of x and the sign of y.
#include <a href="#7.12"><math.h></a>
double nan(const char *tagp);
float nanf(const char *tagp);
- long double nanl(const char *tagp);</pre>
+ long double nanl(const char *tagp);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The call nan("n-char-sequence") is equivalent to strtod("NAN(n-char-
#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);</pre>
+ long double nextafterl(long double x, long double y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The nextafter functions determine the next representable value, in the type of the
#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);</pre>
+ long double nexttowardl(long double x, long double y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The nexttoward functions are equivalent to the nextafter functions except that the
#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);</pre>
+ long double fdiml(long double x, long double y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fdim functions determine the positive difference between their arguments:
<pre>
{x - y if x > y
{
- {+0 if x <= y</pre>
+ {+0 if x <= y
+</pre>
A range error may occur.
<h6>Returns</h6>
<p><!--para 3 -->
#include <a href="#7.12"><math.h></a>
double fmax(double x, double y);
float fmaxf(float x, float y);
- long double fmaxl(long double x, long double y);</pre>
+ long double fmaxl(long double x, long double y);
+</pre>
#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);</pre>
+ long double fminl(long double x, long double y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fmin functions determine the minimum numeric value of their arguments.<sup><a href="#note240"><b>240)</b></a></sup>
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);</pre>
+ long double z);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fma functions compute (x x y) + z, rounded as one ternary operation: they compute
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- int isgreater(real-floating x, real-floating y);</pre>
+ int isgreater(real-floating x, real-floating y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isgreater macro determines whether its first argument is greater than its second
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- int isgreaterequal(real-floating x, real-floating y);</pre>
+ int isgreaterequal(real-floating x, real-floating y);
+</pre>
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- int isless(real-floating x, real-floating y);</pre>
+ int isless(real-floating x, real-floating y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isless macro determines whether its first argument is less than its second
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- int islessequal(real-floating x, real-floating y);</pre>
+ int islessequal(real-floating x, real-floating y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The islessequal macro determines whether its first argument is less than or equal to
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- int islessgreater(real-floating x, real-floating y);</pre>
+ int islessgreater(real-floating x, real-floating y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The islessgreater macro determines whether its first argument is less than or
<p><!--para 1 -->
<pre>
#include <a href="#7.12"><math.h></a>
- int isunordered(real-floating x, real-floating y);</pre>
+ int isunordered(real-floating x, real-floating y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The isunordered macro determines whether its arguments are unordered.
<p><!--para 2 -->
The type declared is
<pre>
- jmp_buf</pre>
+ jmp_buf
+</pre>
which is an array type suitable for holding the information needed to restore a calling
environment. The environment of a call to the setjmp macro consists of information
sufficient for a call to the longjmp function to return execution to the correct block and
<p><!--para 1 -->
<pre>
#include <a href="#7.13"><setjmp.h></a>
- int setjmp(jmp_buf env);</pre>
+ int setjmp(jmp_buf env);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The setjmp macro saves its calling environment in its jmp_buf argument for later use
<p><!--para 1 -->
<pre>
#include <a href="#7.13"><setjmp.h></a>
- _Noreturn void longjmp(jmp_buf env, int val);</pre>
+ _Noreturn void longjmp(jmp_buf env, int val);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The longjmp function restores the environment saved by the most recent invocation of
{
int b[n]; // b may remain allocated
longjmp(buf, 2); // might cause memory loss
- }</pre>
+ }
+</pre>
<h6>footnotes</h6>
<p><small><a name="note245" href="#note245">245)</a> For example, by executing a return statement or because another longjmp call has caused a
<p><!--para 2 -->
The type defined is
<pre>
- sig_atomic_t</pre>
+ sig_atomic_t
+</pre>
which is the (possibly volatile-qualified) integer type of an object that can be accessed as
an atomic entity, even in the presence of asynchronous interrupts.
<p><!--para 3 -->
<pre>
SIG_DFL
SIG_ERR
- SIG_IGN</pre>
+ SIG_IGN
+</pre>
which expand to constant expressions with distinct values that have type compatible with
the second argument to, and the return value of, the signal function, and whose values
compare unequal to the address of any declarable function; and the following, which
SIGILL detection of an invalid function image, such as an invalid instruction
SIGINT receipt of an interactive attention signal
SIGSEGV an invalid access to storage
- SIGTERM a termination request sent to the program</pre>
+ SIGTERM a termination request sent to the program
+</pre>
<p><!--para 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,
<p><!--para 1 -->
<pre>
#include <a href="#7.14"><signal.h></a>
- void (*signal(int sig, void (*func)(int)))(int);</pre>
+ void (*signal(int sig, void (*func)(int)))(int);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The signal function chooses one of three ways in which receipt of the signal number
<p><!--para 6 -->
At program startup, the equivalent of
<pre>
- signal(sig, SIG_IGN);</pre>
+ signal(sig, SIG_IGN);
+</pre>
may be executed for some signals selected in an implementation-defined manner; the
equivalent of
<pre>
- signal(sig, SIG_DFL);</pre>
+ signal(sig, SIG_DFL);
+</pre>
is executed for all other signals defined by the implementation.
<p><!--para 7 -->
The implementation shall behave as if no library function calls the signal function.
<p><!--para 1 -->
<pre>
#include <a href="#7.14"><signal.h></a>
- int raise(int sig);</pre>
+ int raise(int sig);
+</pre>
<h6>Description</h6>
<p><!--para 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
<p><!--para 2 -->
The macro
<pre>
- alignas</pre>
+ alignas
+</pre>
expands to _Alignas.
<p><!--para 3 -->
The remaining macro is suitable for use in #if preprocessing directives. It is
<pre>
- __alignas_is_defined</pre>
+ __alignas_is_defined
+</pre>
which expands to the integer constant 1.
<!--page 286 -->
<p><!--para 3 -->
The type declared is
<pre>
- va_list</pre>
+ va_list
+</pre>
which is a complete object type suitable for holding information needed by the macros
va_start, va_arg, va_end, and va_copy. If access to the varying arguments is
desired, the called function shall declare an object (generally referred to as ap in this
<p><!--para 1 -->
<pre>
#include <a href="#7.16"><stdarg.h></a>
- type va_arg(va_list ap, type);</pre>
+ type va_arg(va_list ap, type);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The va_arg macro expands to an expression that has the specified type and the value of
<p><!--para 1 -->
<pre>
#include <a href="#7.16"><stdarg.h></a>
- void va_copy(va_list dest, va_list src);</pre>
+ void va_copy(va_list dest, va_list src);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The va_copy macro initializes dest as a copy of src, as if the va_start macro had
<p><!--para 1 -->
<pre>
#include <a href="#7.16"><stdarg.h></a>
- void va_end(va_list ap);</pre>
+ void va_end(va_list ap);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The va_end macro facilitates a normal return from the function whose variable
<p><!--para 1 -->
<pre>
#include <a href="#7.16"><stdarg.h></a>
- void va_start(va_list ap, parmN);</pre>
+ void va_start(va_list ap, parmN);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The va_start macro shall be invoked before any access to the unnamed arguments.
array[ptr_no++] = va_arg(ap, char *);
va_end(ap);
f2(n_ptrs, array);
- }</pre>
+ }
+</pre>
Each call to f1 is required to have visible the definition of the function or a declaration such as
<pre>
- void f1(int, ...);</pre>
+ void f1(int, ...);
+</pre>
<p><!--para 7 -->
EXAMPLE 2 The function f3 is similar, but saves the status of the variable argument list after the
array[ptr_no++] = va_arg(ap_save, char *);
va_end(ap_save);
f4(n_ptrs, array);
- }</pre>
+ }
+</pre>
<h3><a name="7.17" href="#7.17">7.17 Atomics <stdatomic.h></a></h3>
ATOMIC_INT_LOCK_FREE
ATOMIC_LONG_LOCK_FREE
ATOMIC_LLONG_LOCK_FREE
- ATOMIC_ADDRESS_LOCK_FREE</pre>
+ ATOMIC_ADDRESS_LOCK_FREE
+</pre>
which indicate the lock-free property of the corresponding atomic types (both signed and
unsigned); and
<pre>
- ATOMIC_FLAG_INIT</pre>
+ ATOMIC_FLAG_INIT
+</pre>
which expands to an initializer for an object of type atomic_flag.
<p><!--para 4 -->
The types include
<pre>
- memory_order</pre>
+ memory_order
+</pre>
which is an enumerated type whose enumerators identify memory ordering constraints;
<pre>
- atomic_flag</pre>
+ atomic_flag
+</pre>
which is a structure type representing a lock-free, primitive atomic flag;
<pre>
- atomic_bool</pre>
+ atomic_bool
+</pre>
which is a structure type representing the atomic analog of the type _Bool;
<pre>
- atomic_address</pre>
+ atomic_address
+</pre>
which is a structure type representing the atomic analog of a pointer type; and several
atomic analogs of integer types.
<p><!--para 5 -->
<p><!--para 1 -->
<pre>
#include <a href="#7.17"><stdatomic.h></a>
- #define ATOMIC_VAR_INIT(C value)</pre>
+ #define ATOMIC_VAR_INIT(C value)
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ATOMIC_VAR_INIT macro expands to a token sequence suitable for initializing an
<p><!--para 4 -->
EXAMPLE
<pre>
- atomic_int guide = ATOMIC_VAR_INIT(42);</pre>
+ atomic_int guide = ATOMIC_VAR_INIT(42);
+</pre>
<h5><a name="7.17.2.2" href="#7.17.2.2">7.17.2.2 The atomic_init generic function</a></h5>
<p><!--para 1 -->
<pre>
#include <a href="#7.17"><stdatomic.h></a>
- void atomic_init(volatile A *obj, C value);</pre>
+ void atomic_init(volatile A *obj, C value);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The atomic_init generic function initializes the atomic object pointed to by obj to
EXAMPLE
<pre>
atomic_int guide;
- atomic_init(&guide, 42);</pre>
+ atomic_init(&guide, 42);
+</pre>
<h4><a name="7.17.3" href="#7.17.3">7.17.3 Order and consistency</a></h4>
memory_order_acquire
memory_order_release
memory_order_acq_rel
- memory_order_seq_cst</pre>
+ memory_order_seq_cst
+</pre>
<p><!--para 2 -->
For memory_order_relaxed, no operation orders memory.
<p><!--para 3 -->
<pre>
// Thread 1:
r1 = atomic_load_explicit(&y, memory_order_relaxed);
- atomic_store_explicit(&x, r1, memory_order_relaxed);</pre>
+ atomic_store_explicit(&x, r1, memory_order_relaxed);
+</pre>
<pre>
// Thread 2:
r2 = atomic_load_explicit(&x, memory_order_relaxed);
- atomic_store_explicit(&y, 42, memory_order_relaxed);</pre>
+ atomic_store_explicit(&y, 42, memory_order_relaxed);
+</pre>
is allowed to produce r1 == 42 && r2 == 42. The sequence of evaluations justifying this consists of:
atomic_store_explicit(&y, 42, memory_order_relaxed);
r1 = atomic_load_explicit(&y, memory_order_relaxed);
atomic_store_explicit(&x, r1, memory_order_relaxed);
- r2 = atomic_load_explicit(&x, memory_order_relaxed);</pre>
+ r2 = atomic_load_explicit(&x, memory_order_relaxed);
+</pre>
On the other hand,
<pre>
// Thread 1:
r1 = atomic_load_explicit(&y, memory_order_relaxed);
- atomic_store_explicit(&x, r1, memory_order_relaxed);</pre>
+ atomic_store_explicit(&x, r1, memory_order_relaxed);
+</pre>
<pre>
// Thread 2:
r2 = atomic_load_explicit(&x, memory_order_relaxed);
- atomic_store_explicit(&y, r2, memory_order_relaxed);</pre>
+ atomic_store_explicit(&y, r2, memory_order_relaxed);
+</pre>
is not allowed to produce r1 == 42 && r2 = 42, since there is no sequence of evaluations that results
in the computation of 42. In the absence of ''relaxed'' operations and read-modify-write operations with
weaker than memory_order_acq_rel ordering, the second requirement has no impact.
// Thread 1:
r1 = atomic_load_explicit(&x, memory_order_relaxed);
if (r1 == 42)
- atomic_store_explicit(&y, r1, memory_order_relaxed);</pre>
+ atomic_store_explicit(&y, r1, memory_order_relaxed);
+</pre>
<pre>
// Thread 2:
r2 = atomic_load_explicit(&y, memory_order_relaxed);
if (r2 == 42)
- atomic_store_explicit(&x, 42, memory_order_relaxed);</pre>
+ atomic_store_explicit(&x, 42, memory_order_relaxed);
+</pre>
However, this is not useful behavior, and implementations should not allow it.
<p><!--para 16 -->
Implementations should make atomic stores visible to atomic loads within a reasonable
<p><!--para 1 -->
<pre>
#include <a href="#7.17"><stdatomic.h></a>
- type kill_dependency(type y);</pre>
+ type kill_dependency(type y);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The kill_dependency macro terminates a dependency chain; the argument does not
<p><!--para 1 -->
<pre>
#include <a href="#7.17"><stdatomic.h></a>
- void atomic_thread_fence(memory_order order);</pre>
+ void atomic_thread_fence(memory_order order);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
Depending on the value of order, this operation:
<p><!--para 1 -->
<pre>
#include <a href="#7.17"><stdatomic.h></a>
- void atomic_signal_fence(memory_order order);</pre>
+ void atomic_signal_fence(memory_order order);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
Equivalent to atomic_thread_fence(order), except that ''synchronizes with''
<p><!--para 1 -->
<pre>
#include <a href="#7.17"><stdatomic.h></a>
- _Bool atomic_is_lock_free(atomic_type const volatile *obj);</pre>
+ _Bool atomic_is_lock_free(atomic_type const volatile *obj);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The atomic_is_lock_free generic function indicates whether or not the object
atomic_size_t _Atomic size_t
atomic_ptrdiff_t _Atomic ptrdiff_t
atomic_intmax_t _Atomic intmax_t
- atomic_uintmax_t _Atomic uintmax_t</pre>
+ atomic_uintmax_t _Atomic uintmax_t
+</pre>
<p><!--para 2 -->
The semantics of the operations on these types are defined in <a href="#7.17.7">7.17.7</a>.
<p><!--para 3 -->
#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);</pre>
+ C desired, memory_order order);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The order argument shall not be memory_order_acquire,
#include <a href="#7.17"><stdatomic.h></a>
C atomic_load(volatile A *object);
C atomic_load_explicit(volatile A *object,
- memory_order order);</pre>
+ memory_order order);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The order argument shall not be memory_order_release nor
#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);</pre>
+ C desired, memory_order order);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
Atomically replace the value pointed to by object with desired. Memory is affected
C *expected, C desired);
_Bool atomic_compare_exchange_weak_explicit(
volatile A *object, C *expected, C desired,
- memory_order success, memory_order failure);</pre>
+ memory_order success, memory_order failure);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The failure argument shall not be memory_order_release nor
if (*object == *expected)
*object = desired;
else
- *expected = *object;</pre>
+ *expected = *object;
+</pre>
<p><!--para 4 -->
The weak compare-and-exchange operations may fail spuriously, that is, return zero
exp = atomic_load(&cur);
do {
des = function(exp);
- } while (!atomic_compare_exchange_weak(&cur, &exp, des));</pre>
+ } while (!atomic_compare_exchange_weak(&cur, &exp, des));
+</pre>
When a compare-and-exchange is in a loop, the weak version will yield better performance on some
platforms. When a weak compare-and-exchange would require a loop and a strong one would not, the
strong one is preferable.
#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);</pre>
+ M operand, memory_order order);
+</pre>
<h6>Description</h6>
<p><!--para 3 -->
Atomically replaces the value pointed to by object with the result of the computation
<p><!--para 5 -->
EXAMPLE
<pre>
- atomic_flag guard = ATOMIC_FLAG_INIT;</pre>
+ atomic_flag guard = ATOMIC_FLAG_INIT;
+</pre>
<h5><a name="7.17.8.1" href="#7.17.8.1">7.17.8.1 The atomic_flag_test_and_set functions</a></h5>
bool atomic_flag_test_and_set(
volatile atomic_flag *object);
bool atomic_flag_test_and_set_explicit(
- volatile atomic_flag *object, memory_order order);</pre>
+ volatile atomic_flag *object, memory_order order);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
Atomically sets the value pointed to by object to true. Memory is affected according
#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);</pre>
+ volatile atomic_flag *object, memory_order order);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The order argument shall not be memory_order_acquire nor
<p><!--para 2 -->
The macro
<pre>
- bool</pre>
+ bool
+</pre>
expands to _Bool.
<p><!--para 3 -->
The remaining three macros are suitable for use in #if preprocessing directives. They
are
<pre>
- true</pre>
+ true
+</pre>
which expands to the integer constant 1,
<pre>
- false</pre>
+ false
+</pre>
which expands to the integer constant 0, and
<pre>
- __bool_true_false_are_defined</pre>
+ __bool_true_false_are_defined
+</pre>
which expands to the integer constant 1.
<p><!--para 4 -->
Notwithstanding the provisions of <a href="#7.1.3">7.1.3</a>, a program may undefine and perhaps then
<p><!--para 2 -->
The types are
<pre>
- ptrdiff_t</pre>
+ ptrdiff_t
+</pre>
which is the signed integer type of the result of subtracting two pointers;
<pre>
- size_t</pre>
+ size_t
+</pre>
which is the unsigned integer type of the result of the sizeof operator;
<pre>
- max_align_t</pre>
+ max_align_t
+</pre>
which is an object type whose alignment is as great as is supported by the implementation
in all contexts; and
<pre>
- wchar_t</pre>
+ wchar_t
+</pre>
which is an integer type whose range of values can represent distinct codes for all
members of the largest extended character set specified among the supported locales; the
null character shall have the code value zero. Each member of the basic character set
<p><!--para 3 -->
The macros are
<pre>
- NULL</pre>
+ NULL
+</pre>
which expands to an implementation-defined null pointer constant; and
<pre>
- offsetof(type, member-designator)</pre>
+ offsetof(type, member-designator)
+</pre>
which expands to an integer constant expression that has type size_t, the value of
which is the offset in bytes, to the structure member (designated by member-designator),
from the beginning of its structure (designated by type). The type and member designator
shall be such that given
<pre>
- static type t;</pre>
+ static type t;
+</pre>
then the expression &(t.member-designator) evaluates to an address constant. (If the
specified member is a bit-field, the behavior is undefined.)
<h6>Recommended practice</h6>
int_least8_t uint_least8_t
int_least16_t uint_least16_t
int_least32_t uint_least32_t
- int_least64_t uint_least64_t</pre>
+ int_least64_t uint_least64_t
+</pre>
All other types of this form are optional.
<h5><a name="7.20.1.3" href="#7.20.1.3">7.20.1.3 Fastest minimum-width integer types</a></h5>
int_fast8_t uint_fast8_t
int_fast16_t uint_fast16_t
int_fast32_t uint_fast32_t
- int_fast64_t uint_fast64_t</pre>
+ int_fast64_t uint_fast64_t
+</pre>
All other types of this form are optional.
<h6>footnotes</h6>
pointer to void can be converted to this type, then converted back to pointer to void,
and the result will compare equal to the original pointer:
<pre>
- intptr_t</pre>
+ intptr_t
+</pre>
The following type designates an unsigned integer type with the property that any valid
pointer to void can be converted to this type, then converted back to pointer to void,
and the result will compare equal to the original pointer:
<pre>
- uintptr_t</pre>
+ uintptr_t
+</pre>
These types are optional.
<h5><a name="7.20.1.5" href="#7.20.1.5">7.20.1.5 Greatest-width integer types</a></h5>
The following type designates a signed integer type capable of representing any value of
any signed integer type:
<pre>
- intmax_t</pre>
+ intmax_t
+</pre>
The following type designates an unsigned integer type capable of representing any value
of any unsigned integer type:
<pre>
- uintmax_t</pre>
+ uintmax_t
+</pre>
These types are required.
<h4><a name="7.20.2" href="#7.20.2">7.20.2 Limits of specified-width integer types</a></h4>
<ul>
<li> minimum values of exact-width signed integer types
<pre>
- INTN_MIN exactly -(2 N -1 )</pre>
+ INTN_MIN exactly -(2 N -1 )
+</pre>
<li> maximum values of exact-width signed integer types
<pre>
- INTN_MAX exactly 2 N -1 - 1</pre>
+ INTN_MAX exactly 2 N -1 - 1
+</pre>
<li> maximum values of exact-width unsigned integer types
UINTN_MAX exactly 2 N - 1
</ul>
<ul>
<li> minimum values of minimum-width signed integer types
<pre>
- INT_LEASTN_MIN -(2 N -1 - 1)</pre>
+ INT_LEASTN_MIN -(2 N -1 - 1)
+</pre>
<li> maximum values of minimum-width signed integer types
<pre>
- INT_LEASTN_MAX 2 N -1 - 1</pre>
+ INT_LEASTN_MAX 2 N -1 - 1
+</pre>
<li> maximum values of minimum-width unsigned integer types
UINT_LEASTN_MAX 2N - 1
</ul>
<ul>
<li> minimum values of fastest minimum-width signed integer types
<pre>
- INT_FASTN_MIN -(2 N -1 - 1)</pre>
+ INT_FASTN_MIN -(2 N -1 - 1)
+</pre>
<li> maximum values of fastest minimum-width signed integer types
INT_FASTN_MAX 2 N -1 - 1
<li> maximum values of fastest minimum-width unsigned integer types
<ul>
<li> minimum value of pointer-holding signed integer type
<pre>
- INTPTR_MIN -(215 - 1)</pre>
+ INTPTR_MIN -(215 - 1)
+</pre>
<li> maximum value of pointer-holding signed integer type
INTPTR_MAX 215 - 1
<li> maximum value of pointer-holding unsigned integer type
The following macro expands to an integer constant expression having the value specified
by its argument and the type intmax_t:
<pre>
- INTMAX_C(value)</pre>
+ INTMAX_C(value)
+</pre>
The following macro expands to an integer constant expression having the value specified
by its argument and the type uintmax_t:
<!--page 314 -->
<pre>
- UINTMAX_C(value)</pre>
+ UINTMAX_C(value)
+</pre>
<h3><a name="7.21" href="#7.21">7.21 Input/output <stdio.h></a></h3>
<p><!--para 2 -->
The types declared are size_t (described in <a href="#7.19">7.19</a>);
<pre>
- FILE</pre>
+ FILE
+</pre>
which is an object type capable of recording all the information needed to control a
stream, including its file position indicator, a pointer to its associated buffer (if any), an
error indicator that records whether a read/write error has occurred, and an end-of-file
indicator that records whether the end of the file has been reached; and
<pre>
- fpos_t</pre>
+ fpos_t
+</pre>
which is a complete object type other than an array type capable of recording all the
information needed to specify uniquely every position within a file.
<p><!--para 3 -->
<pre>
_IOFBF
_IOLBF
- _IONBF</pre>
+ _IONBF
+</pre>
which expand to integer constant expressions with distinct values, suitable for use as the
third argument to the setvbuf function;
<pre>
- BUFSIZ</pre>
+ BUFSIZ
+</pre>
which expands to an integer constant expression that is the size of the buffer used by the
setbuf function;
<pre>
- EOF</pre>
+ EOF
+</pre>
which expands to an integer constant expression, with type int and a negative value, that
is returned by several functions to indicate end-of-file, that is, no more input from a
stream;
<pre>
- FOPEN_MAX</pre>
+ FOPEN_MAX
+</pre>
which expands to an integer constant expression that is the minimum number of files that
the implementation guarantees can be open simultaneously;
<pre>
- FILENAME_MAX</pre>
+ FILENAME_MAX
+</pre>
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
<!--page 315 -->
guarantees can be opened;<sup><a href="#note258"><b>258)</b></a></sup>
<pre>
- L_tmpnam</pre>
+ L_tmpnam
+</pre>
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
function;
<pre>
SEEK_CUR
SEEK_END
- SEEK_SET</pre>
+ SEEK_SET
+</pre>
which expand to integer constant expressions with distinct values, suitable for use as the
third argument to the fseek function;
<pre>
- TMP_MAX</pre>
+ TMP_MAX
+</pre>
which expands to an integer constant expression that is the minimum number of unique
file names that can be generated by the tmpnam function;
<pre>
stderr
stdin
- stdout</pre>
+ stdout
+</pre>
which are expressions of type ''pointer to FILE'' that point to the FILE objects
associated, respectively, with the standard error, input, and output streams.
<p><!--para 4 -->
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int remove(const char *filename);</pre>
+ int remove(const char *filename);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The remove function causes the file whose name is the string pointed to by filename
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int rename(const char *old, const char *new);</pre>
+ int rename(const char *old, const char *new);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The rename function causes the file whose name is the string pointed to by old to be
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- FILE *tmpfile(void);</pre>
+ FILE *tmpfile(void);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The tmpfile function creates a temporary binary file that is different from any other
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- char *tmpnam(char *s);</pre>
+ char *tmpnam(char *s);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The tmpnam function generates a string that is a valid file name and that is not the same
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int fclose(FILE *stream);</pre>
+ int fclose(FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
A successful call to the fclose function causes the stream pointed to by stream to be
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int fflush(FILE *stream);</pre>
+ int fflush(FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If stream points to an output stream or an update stream in which the most recent
<pre>
#include <a href="#7.21"><stdio.h></a>
FILE *fopen(const char * restrict filename,
- const char * restrict mode);</pre>
+ const char * restrict mode);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fopen function opens the file whose name is the string pointed to by filename,
#include <a href="#7.21"><stdio.h></a>
FILE *freopen(const char * restrict filename,
const char * restrict mode,
- FILE * restrict stream);</pre>
+ FILE * restrict stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The freopen function opens the file whose name is the string pointed to by filename
<pre>
#include <a href="#7.21"><stdio.h></a>
void setbuf(FILE * restrict stream,
- char * restrict buf);</pre>
+ char * restrict buf);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
Except that it returns no value, the setbuf function is equivalent to the setvbuf
#include <a href="#7.21"><stdio.h></a>
int setvbuf(FILE * restrict stream,
char * restrict buf,
- int mode, size_t size);</pre>
+ int mode, size_t size);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The setvbuf function may be used only after the stream pointed to by stream has
<pre>
#include <a href="#7.21"><stdio.h></a>
int fprintf(FILE * restrict stream,
- const char * restrict format, ...);</pre>
+ const char * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fprintf function writes output to the stream pointed to by stream, under control
The flag characters and their meanings are:
- The result of the conversion is left-justified within the field. (It is right-justified if
<pre>
- this flag is not specified.)</pre>
+ this flag is not specified.)
+</pre>
+ The result of a signed conversion always begins with a plus or minus sign. (It
<pre>
begins with a sign only when a negative value is converted if this flag is not
- specified.)<sup><a href="#note269"><b>269)</b></a></sup></pre>
+ specified.)<sup><a href="#note269"><b>269)</b></a></sup>
+</pre>
space If the first character of a signed conversion is not a sign, or if a signed conversion
<pre>
results in no characters, a space is prefixed to the result. If the space and + flags
- both appear, the space flag is ignored.</pre>
+ both appear, the space flag is ignored.
+</pre>
# The result is converted to an ''alternative form''. For o conversion, it increases
<pre>
the precision, if and only if necessary, to force the first digit of the result to be a
contains a decimal-point character, even if no digits follow it. (Normally, a
decimal-point character appears in the result of these conversions only if a digit
follows it.) For g and G conversions, trailing zeros are not removed from the
- result. For other conversions, the behavior is undefined.</pre>
+ result. For other conversions, the behavior is undefined.
+</pre>
0 For d, i, o, u, x, X, a, A, e, E, f, F, g, and G conversions, leading zeros
<pre>
(following any indication of sign or base) are used to pad to the field width rather
than performing space padding, except when converting an infinity or NaN. If the
- 0 and - flags both appear, the 0 flag is ignored. For d, i, o, u, x, and X</pre>
+ 0 and - flags both appear, the 0 flag is ignored. For d, i, o, u, x, and X
+</pre>
<!--page 329 -->
<pre>
conversions, if a precision is specified, the 0 flag is ignored. For other
- conversions, the behavior is undefined.</pre>
+ conversions, the behavior is undefined.
+</pre>
<p><!--para 7 -->
The length modifiers and their meanings are:
hh Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
been promoted according to the integer promotions, but its value shall be
converted to signed char or unsigned char before printing); or that
a following n conversion specifier applies to a pointer to a signed char
- argument.</pre>
+ argument.
+</pre>
h Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
<pre>
short int or unsigned short int argument (the argument will
have been promoted according to the integer promotions, but its value shall
be converted to short int or unsigned short int before printing);
or that a following n conversion specifier applies to a pointer to a short
- int argument.</pre>
+ int argument.
+</pre>
l (ell) Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
<pre>
long int or unsigned long int argument; that a following n
following c conversion specifier applies to a wint_t argument; that a
following s conversion specifier applies to a pointer to a wchar_t
argument; or has no effect on a following a, A, e, E, f, F, g, or G conversion
- specifier.</pre>
+ specifier.
+</pre>
ll (ell-ell) Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
<pre>
long long int or unsigned long long int argument; or that a
following n conversion specifier applies to a pointer to a long long int
- argument.</pre>
+ argument.
+</pre>
j Specifies that a following d, i, o, u, x, or X conversion specifier applies to
<pre>
an intmax_t or uintmax_t argument; or that a following n conversion
- specifier applies to a pointer to an intmax_t argument.</pre>
+ specifier applies to a pointer to an intmax_t argument.
+</pre>
z Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
<pre>
size_t or the corresponding signed integer type argument; or that a
following n conversion specifier applies to a pointer to a signed integer type
- corresponding to size_t argument.</pre>
+ corresponding to size_t argument.
+</pre>
t Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
<!--page 330 -->
<pre>
ptrdiff_t or the corresponding unsigned integer type argument; or that a
following n conversion specifier applies to a pointer to a ptrdiff_t
- argument.</pre>
+ argument.
+</pre>
L Specifies that a following a, A, e, E, f, F, g, or G conversion specifier
<pre>
- applies to a long double argument.</pre>
+ applies to a long double argument.
+</pre>
If a length modifier appears with any conversion specifier other than as specified above,
the behavior is undefined.
<p><!--para 8 -->
precision specifies the minimum number of digits to appear; if the value
being converted can be represented in fewer digits, it is expanded with
leading zeros. The default precision is 1. The result of converting a zero
- value with a precision of zero is no characters.</pre>
+ value with a precision of zero is no characters.
+</pre>
o,u,x,X The unsigned int argument is converted to unsigned octal (o), unsigned
<pre>
decimal (u), or unsigned hexadecimal notation (x or X) in the style dddd; the
conversion. The precision specifies the minimum number of digits to appear;
if the value being converted can be represented in fewer digits, it is expanded
with leading zeros. The default precision is 1. The result of converting a
- zero value with a precision of zero is no characters.</pre>
+ zero value with a precision of zero is no characters.
+</pre>
f,F A double argument representing a floating-point number is converted to
<pre>
decimal notation in the style [-]ddd.ddd, where the number of digits after
[-]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.<sup><a href="#note270"><b>270)</b></a></sup></pre>
+ respectively.<sup><a href="#note270"><b>270)</b></a></sup>
+</pre>
e,E A double argument representing a floating-point number is converted in the
<pre>
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</pre>
+ digits after it is equal to the precision; if the precision is missing, it is taken as
+</pre>
<!--page 331 -->
and only as many more digits as necessary to represent the exponent. If the
value is zero, the exponent is zero.
A double argument representing an infinity or NaN is converted in the style
- of an f or F conversion specifier.</pre>
+ of an f or F conversion specifier.
+</pre>
g,G A double argument representing a floating-point number is converted in
<pre>
style f or e (or in style F or E in the case of a G conversion specifier),
fractional portion of the result and the decimal-point character is removed if
there is no fractional portion remaining.
A double argument representing an infinity or NaN is converted in the style
- of an f or F conversion specifier.</pre>
+ of an f or F conversion specifier.
+</pre>
a,A A double argument representing a floating-point number is converted in the
<pre>
style [-]0xh.hhhh p(+-)d, where there is one hexadecimal digit (which is
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
- FLT_RADIX is not a power of 2, then the precision is sufficient to</pre>
+ FLT_RADIX is not a power of 2, then the precision is sufficient to
+</pre>
least one digit, and only as many more digits as necessary to represent the
decimal exponent of 2. If the value is zero, the exponent is zero.
A double argument representing an infinity or NaN is converted in the style
- of an f or F conversion specifier.</pre>
+ of an f or F conversion specifier.
+</pre>
c If no l length modifier is present, the int argument is converted to an
<pre>
unsigned char, and the resulting character is written.
an ls conversion specification with no precision and an argument that points
to the initial element of a two-element array of wchar_t, the first element
containing the wint_t argument to the lc conversion specification and the
- second a null wide character.</pre>
+ second a null wide character.
+</pre>
s If no l length modifier is present, the argument shall be a pointer to the initial
<pre>
element of an array of character type.<sup><a href="#note273"><b>273)</b></a></sup> Characters from the array are
(byte). If no precision is specified, the array shall contain a null wide
character. If a precision is specified, no more than that many bytes are
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</pre>
+ wide character if, to equal the multibyte character sequence length given by
+</pre>
<!--page 333 -->
<pre>
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.<sup><a href="#note274"><b>274)</b></a></sup></pre>
+ end of the array. In no case is a partial multibyte character written.<sup><a href="#note274"><b>274)</b></a></sup>
+</pre>
p The argument shall be a pointer to void. The value of the pointer is
<pre>
converted to a sequence of printing characters, in an implementation-defined
- manner.</pre>
+ manner.
+</pre>
n The argument shall be a pointer to signed integer into which is written the
<pre>
number of characters written to the output stream so far by this call to
fprintf. No argument is converted, but one is consumed. If the conversion
specification includes any flags, a field width, or a precision, the behavior is
- undefined.</pre>
+ undefined.
+</pre>
% A % character is written. No argument is converted. The complete
<pre>
- conversion specification shall be %%.</pre>
+ conversion specification shall be %%.
+</pre>
<p><!--para 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
int day, hour, min;
fprintf(stdout, "%s, %s %d, %.2d:%.2d\n",
weekday, month, day, hour, min);
- fprintf(stdout, "pi = %.5f\n", 4 * atan(1.0));</pre>
+ fprintf(stdout, "pi = %.5f\n", 4 * atan(1.0));
+</pre>
<p><!--para 17 -->
EXAMPLE 2 In this example, multibyte characters do not have a state-dependent encoding, and the
<p><!--para 18 -->
Given the following wide string with length seven,
<pre>
- static wchar_t wstr[] = L" X Yabc Z W";</pre>
+ static wchar_t wstr[] = L" X Yabc Z W";
+</pre>
the seven calls
<pre>
fprintf(stdout, "|1234567890123|\n");
fprintf(stdout, "|%13.10ls|\n", wstr);
fprintf(stdout, "|%13.11ls|\n", wstr);
fprintf(stdout, "|%13.15ls|\n", &wstr[2]);
- fprintf(stdout, "|%13lc|\n", (wint_t) wstr[5]);</pre>
+ fprintf(stdout, "|%13lc|\n", (wint_t) wstr[5]);
+</pre>
will print the following seven lines:
<pre>
|1234567890123|
| X Yabc Z|
| X Yabc Z W|
| abc Z W|
- | Z|</pre>
+ | Z|
+</pre>
<p><b> Forward references</b>: 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>).
<!--page 335 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
int fscanf(FILE * restrict stream,
- const char * restrict format, ...);</pre>
+ const char * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fscanf function reads input from the stream pointed to by stream, under control
The length modifiers and their meanings are:
hh Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
- to an argument with type pointer to signed char or unsigned char.</pre>
+ to an argument with type pointer to signed char or unsigned char.
+</pre>
h Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
to an argument with type pointer to short int or unsigned short
- int.</pre>
+ int.
+</pre>
l (ell) Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
to an argument with type pointer to long int or unsigned long
int; that a following a, A, e, E, f, F, g, or G conversion specifier applies to
an argument with type pointer to double; or that a following c, s, or [
- conversion specifier applies to an argument with type pointer to wchar_t.</pre>
+ conversion specifier applies to an argument with type pointer to wchar_t.
+</pre>
ll (ell-ell) Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
to an argument with type pointer to long long int or unsigned
- long long int.</pre>
+ long long int.
+</pre>
<!--page 337 -->
j Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
- to an argument with type pointer to intmax_t or uintmax_t.</pre>
+ to an argument with type pointer to intmax_t or uintmax_t.
+</pre>
z Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
to an argument with type pointer to size_t or the corresponding signed
- integer type.</pre>
+ integer type.
+</pre>
t Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
to an argument with type pointer to ptrdiff_t or the corresponding
- unsigned integer type.</pre>
+ unsigned integer type.
+</pre>
L Specifies that a following a, A, e, E, f, F, g, or G conversion specifier
<pre>
- applies to an argument with type pointer to long double.</pre>
+ applies to an argument with type pointer to long double.
+</pre>
If a length modifier appears with any conversion specifier other than as specified above,
the behavior is undefined.
<p><!--para 12 -->
<pre>
expected for the subject sequence of the strtol function with the value 10
for the base argument. The corresponding argument shall be a pointer to
- signed integer.</pre>
+ signed integer.
+</pre>
i Matches an optionally signed integer, whose format is the same as expected
<pre>
for the subject sequence of the strtol function with the value 0 for the
base argument. The corresponding argument shall be a pointer to signed
- integer.</pre>
+ integer.
+</pre>
o Matches an optionally signed octal integer, whose format is the same as
<pre>
expected for the subject sequence of the strtoul function with the value 8
for the base argument. The corresponding argument shall be a pointer to
- unsigned integer.</pre>
+ unsigned integer.
+</pre>
u Matches an optionally signed decimal integer, whose format is the same as
<pre>
expected for the subject sequence of the strtoul function with the value 10
for the base argument. The corresponding argument shall be a pointer to
- unsigned integer.</pre>
+ unsigned integer.
+</pre>
x Matches an optionally signed hexadecimal integer, whose format is the same
<pre>
as expected for the subject sequence of the strtoul function with the value
16 for the base argument. The corresponding argument shall be a pointer to
- unsigned integer.</pre>
+ unsigned integer.
+</pre>
a,e,f,g Matches an optionally signed floating-point number, infinity, or NaN, whose
<!--page 338 -->
<pre>
format is the same as expected for the subject sequence of the strtod
- function. The corresponding argument shall be a pointer to floating.</pre>
+ function. The corresponding argument shall be a pointer to floating.
+</pre>
c Matches a sequence of characters of exactly the number specified by the field
<pre>
width (1 if no field width is present in the directive).<sup><a href="#note279"><b>279)</b></a></sup>
initialized to zero 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 to accept the resulting sequence of wide characters.
- No null wide character is added.</pre>
+ No null wide character is added.
+</pre>
s Matches a sequence of non-white-space characters.<sup><a href="#note279"><b>279)</b></a></sup>
<pre>
If no l length modifier is present, the corresponding argument shall be a
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
to accept the sequence and the terminating null wide character, which will be
- added automatically.</pre>
+ added automatically.
+</pre>
[ Matches a nonempty sequence of characters from a set of expected characters
<pre>
(the scanset).<sup><a href="#note279"><b>279)</b></a></sup>
If an l length modifier is present, the input shall be a sequence of multibyte
characters that begins in the initial shift state. Each multibyte character is
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</pre>
+ the conversion state described by an mbstate_t object initialized to zero
+</pre>
<!--page 339 -->
<pre>
the first following right bracket character is the one that ends the
specification. If a - character is in the scanlist and is not the first, nor the
second where the first character is a ^, nor the last character, the behavior is
- implementation-defined.</pre>
+ implementation-defined.
+</pre>
p Matches an implementation-defined set of sequences, which should be the
<pre>
same as the set of sequences that may be produced by the %p conversion of
pointer to void. The input item is converted to a pointer value in an
implementation-defined manner. If the input item is a value converted earlier
during the same program execution, the pointer that results shall compare
- equal to that value; otherwise the behavior of the %p conversion is undefined.</pre>
+ equal to that value; otherwise the behavior of the %p conversion is undefined.
+</pre>
n No input is consumed. The corresponding argument shall be a pointer to
<pre>
signed integer into which is to be written the number of characters read from
%n directive does not increment the assignment count returned at the
completion of execution of the fscanf function. No argument is converted,
but one is consumed. If the conversion specification includes an assignment-
- suppressing character or a field width, the behavior is undefined.</pre>
+ suppressing character or a field width, the behavior is undefined.
+</pre>
% Matches a single % character; no conversion or assignment occurs. The
<pre>
- complete conversion specification shall be %%.</pre>
+ complete conversion specification shall be %%.
+</pre>
<p><!--para 13 -->
If a conversion specification is invalid, the behavior is undefined.<sup><a href="#note280"><b>280)</b></a></sup>
<p><!--para 14 -->
#include <a href="#7.21"><stdio.h></a>
/* ... */
int n, i; float x; char name[50];
- n = fscanf(stdin, "%d%f%s", &i, &x, name);</pre>
+ n = fscanf(stdin, "%d%f%s", &i, &x, name);
+</pre>
with the input line:
<pre>
- 25 54.32E-1 thompson</pre>
+ 25 54.32E-1 thompson
+</pre>
will assign to n the value 3, to i the value 25, to x the value 5.432, and to name the sequence
thompson\0.
#include <a href="#7.21"><stdio.h></a>
/* ... */
int i; float x; char name[50];
- fscanf(stdin, "%2d%f%*d %[0123456789]", &i, &x, name);</pre>
+ fscanf(stdin, "%2d%f%*d %[0123456789]", &i, &x, name);
+</pre>
with input:
<pre>
- 56789 0123 56a72</pre>
+ 56789 0123 56a72
+</pre>
will assign to i the value 56 and to x the value 789.0, will skip 0123, and will assign to name the
sequence 56\0. The next character read from the input stream will be a.
do {
count = fscanf(stdin, "%f%20s of %20s", &quant, units, item);
fscanf(stdin,"%*[^\n]");
- } while (!feof(stdin) && !ferror(stdin));</pre>
+ } while (!feof(stdin) && !ferror(stdin));
+</pre>
<p><!--para 20 -->
If the stdin stream contains the following lines:
<!--page 341 -->
lots of luck
10.0LBS of
dirt
- 100ergs of energy</pre>
+ 100ergs of energy
+</pre>
the execution of the above example will be analogous to the following assignments:
<pre>
quant = 2; strcpy(units, "quarts"); strcpy(item, "oil");
quant = 10.0; strcpy(units, "LBS"); strcpy(item, "dirt");
count = 3;
count = 0; // "100e" fails to match "%f"
- count = EOF;</pre>
+ count = EOF;
+</pre>
<p><!--para 21 -->
EXAMPLE 4 In:
#include <a href="#7.21"><stdio.h></a>
/* ... */
int d1, d2, n1, n2, i;
- i = sscanf("123", "%d%n%n%d", &d1, &n1, &n2, &d2);</pre>
+ i = sscanf("123", "%d%n%n%d", &d1, &n1, &n2, &d2);
+</pre>
the value 123 is assigned to d1 and the value 3 to n1. Because %n can never get an input failure the value
of 3 is also assigned to n2. The value of d2 is not affected. The value 1 is assigned to i.
#include <a href="#7.21"><stdio.h></a>
/* ... */
char str[50];
- fscanf(stdin, "a%s", str);</pre>
+ fscanf(stdin, "a%s", str);
+</pre>
with the input line:
<pre>
- a(uparrow) X Y(downarrow) bc</pre>
+ a(uparrow) X Y(downarrow) bc
+</pre>
str will contain (uparrow) X Y(downarrow)\0 assuming that none of the bytes of the shift sequences (or of the multibyte
characters, in the more general case) appears to be a single-byte white-space character.
<p><!--para 24 -->
#include <a href="#7.19"><stddef.h></a>
/* ... */
wchar_t wstr[50];
- fscanf(stdin, "a%ls", wstr);</pre>
+ fscanf(stdin, "a%ls", wstr);
+</pre>
with the same input line, wstr will contain the two wide characters that correspond to X and Y and a
terminating null wide character.
<p><!--para 25 -->
#include <a href="#7.19"><stddef.h></a>
/* ... */
wchar_t wstr[50];
- fscanf(stdin, "a(uparrow) X(downarrow)%ls", wstr);</pre>
+ fscanf(stdin, "a(uparrow) X(downarrow)%ls", wstr);
+</pre>
with the same input line will return zero due to a matching failure against the (downarrow) sequence in the format
string.
<p><!--para 26 -->
#include <a href="#7.19"><stddef.h></a>
/* ... */
wchar_t wstr[50];
- fscanf(stdin, "a(uparrow) Y(downarrow)%ls", wstr);</pre>
+ fscanf(stdin, "a(uparrow) Y(downarrow)%ls", wstr);
+</pre>
with the same input line, zero will again be returned, but stdin will be left with a partially consumed
multibyte character.
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int printf(const char * restrict format, ...);</pre>
+ int printf(const char * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The printf function is equivalent to fprintf with the argument stdout interposed
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int scanf(const char * restrict format, ...);</pre>
+ int scanf(const char * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The scanf function is equivalent to fscanf with the argument stdin interposed
<pre>
#include <a href="#7.21"><stdio.h></a>
int snprintf(char * restrict s, size_t n,
- const char * restrict format, ...);</pre>
+ const char * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The snprintf function is equivalent to fprintf, except that the output is written into
<pre>
#include <a href="#7.21"><stdio.h></a>
int sprintf(char * restrict s,
- const char * restrict format, ...);</pre>
+ const char * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The sprintf function is equivalent to fprintf, except that the output is written into
<pre>
#include <a href="#7.21"><stdio.h></a>
int sscanf(const char * restrict s,
- const char * restrict format, ...);</pre>
+ const char * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The sscanf function is equivalent to fscanf, except that input is obtained from a
#include <a href="#7.21"><stdio.h></a>
int vfprintf(FILE * restrict stream,
const char * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vfprintf function is equivalent to fprintf, with the variable argument list
// print out remainder of message
vfprintf(stderr, format, args);
va_end(args);
- }</pre>
+ }
+</pre>
<h6>footnotes</h6>
#include <a href="#7.21"><stdio.h></a>
int vfscanf(FILE * restrict stream,
const char * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vfscanf function is equivalent to fscanf, with the variable argument list
#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);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vprintf function is equivalent to printf, with the variable argument list
#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);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vscanf function is equivalent to scanf, with the variable argument list replaced
#include <a href="#7.21"><stdio.h></a>
int vsnprintf(char * restrict s, size_t n,
const char * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vsnprintf function is equivalent to snprintf, with the variable argument list
#include <a href="#7.21"><stdio.h></a>
int vsprintf(char * restrict s,
const char * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vsprintf function is equivalent to sprintf, with the variable argument list
#include <a href="#7.21"><stdio.h></a>
int vsscanf(const char * restrict s,
const char * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vsscanf function is equivalent to sscanf, with the variable argument list
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int fgetc(FILE *stream);</pre>
+ int fgetc(FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If the end-of-file indicator for the input stream pointed to by stream is not set and a
<pre>
#include <a href="#7.21"><stdio.h></a>
char *fgets(char * restrict s, int n,
- FILE * restrict stream);</pre>
+ FILE * restrict stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fgets function reads at most one less than the number of characters specified by n
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int fputc(int c, FILE *stream);</pre>
+ int fputc(int c, FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fputc function writes the character specified by c (converted to an unsigned
<pre>
#include <a href="#7.21"><stdio.h></a>
int fputs(const char * restrict s,
- FILE * restrict stream);</pre>
+ FILE * restrict stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fputs function writes the string pointed to by s to the stream pointed to by
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int getc(FILE *stream);</pre>
+ int getc(FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The getc function is equivalent to fgetc, except that if it is implemented as a macro, it
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int getchar(void);</pre>
+ int getchar(void);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The getchar function is equivalent to getc with the argument stdin.
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int putc(int c, FILE *stream);</pre>
+ int putc(int c, FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The putc function is equivalent to fputc, except that if it is implemented as a macro, it
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int putchar(int c);</pre>
+ int putchar(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The putchar function is equivalent to putc with the second argument stdout.
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int puts(const char *s);</pre>
+ int puts(const char *s);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The puts function writes the string pointed to by s to the stream pointed to by stdout,
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int ungetc(int c, FILE *stream);</pre>
+ int ungetc(int c, FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ungetc function pushes the character specified by c (converted to an unsigned
#include <a href="#7.21"><stdio.h></a>
size_t fread(void * restrict ptr,
size_t size, size_t nmemb,
- FILE * restrict stream);</pre>
+ FILE * restrict stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fread function reads, into the array pointed to by ptr, up to nmemb elements
#include <a href="#7.21"><stdio.h></a>
size_t fwrite(const void * restrict ptr,
size_t size, size_t nmemb,
- FILE * restrict stream);</pre>
+ FILE * restrict stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fwrite function writes, from the array pointed to by ptr, up to nmemb elements
<pre>
#include <a href="#7.21"><stdio.h></a>
int fgetpos(FILE * restrict stream,
- fpos_t * restrict pos);</pre>
+ fpos_t * restrict pos);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fgetpos function stores the current values of the parse state (if any) and file
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int fseek(FILE *stream, long int offset, int whence);</pre>
+ int fseek(FILE *stream, long int offset, int whence);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fseek function sets the file position indicator for the stream pointed to by stream.
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int fsetpos(FILE *stream, const fpos_t *pos);</pre>
+ int fsetpos(FILE *stream, const fpos_t *pos);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fsetpos function sets the mbstate_t object (if any) and file position indicator
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- long int ftell(FILE *stream);</pre>
+ long int ftell(FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ftell function obtains the current value of the file position indicator for the stream
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- void rewind(FILE *stream);</pre>
+ void rewind(FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 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
<pre>
- (void)fseek(stream, 0L, SEEK_SET)</pre>
+ (void)fseek(stream, 0L, SEEK_SET)
+</pre>
except that the error indicator for the stream is also cleared.
<h6>Returns</h6>
<p><!--para 3 -->
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- void clearerr(FILE *stream);</pre>
+ void clearerr(FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The clearerr function clears the end-of-file and error indicators for the stream pointed
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int feof(FILE *stream);</pre>
+ int feof(FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The feof function tests the end-of-file indicator for the stream pointed to by stream.
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- int ferror(FILE *stream);</pre>
+ int ferror(FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ferror function tests the error indicator for the stream pointed to by stream.
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><stdio.h></a>
- void perror(const char *s);</pre>
+ void perror(const char *s);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The perror function maps the error number in the integer expression errno to an
<p><!--para 2 -->
The types declared are size_t and wchar_t (both described in <a href="#7.19">7.19</a>),
<pre>
- div_t</pre>
+ div_t
+</pre>
which is a structure type that is the type of the value returned by the div function,
<pre>
- ldiv_t</pre>
+ ldiv_t
+</pre>
which is a structure type that is the type of the value returned by the ldiv function, and
<pre>
- lldiv_t</pre>
+ lldiv_t
+</pre>
which is a structure type that is the type of the value returned by the lldiv function.
<p><!--para 3 -->
The macros defined are NULL (described in <a href="#7.19">7.19</a>);
<pre>
- EXIT_FAILURE</pre>
+ EXIT_FAILURE
+</pre>
and
<pre>
- EXIT_SUCCESS</pre>
+ EXIT_SUCCESS
+</pre>
which expand to integer constant expressions that can be used as the argument to the
exit function to return unsuccessful or successful termination status, respectively, to the
host environment;
<pre>
- RAND_MAX</pre>
+ RAND_MAX
+</pre>
which expands to an integer constant expression that is the maximum value returned by
the rand function; and
<pre>
- MB_CUR_MAX</pre>
+ MB_CUR_MAX
+</pre>
which expands to a positive integer expression with type size_t that is the maximum
number of bytes in a multibyte character for the extended character set specified by the
current locale (category LC_CTYPE), which is never greater than MB_LEN_MAX.
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- double atof(const char *nptr);</pre>
+ double atof(const char *nptr);
+</pre>
<h6>Description</h6>
<p><!--para 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
<pre>
- strtod(nptr, (char **)NULL)</pre>
+ strtod(nptr, (char **)NULL)
+</pre>
<h6>Returns</h6>
<p><!--para 3 -->
The atof function returns the converted value.
#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);</pre>
+ long long int atoll(const char *nptr);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The atoi, atol, and atoll functions convert the initial portion of the string pointed
<pre>
atoi: (int)strtol(nptr, (char **)NULL, 10)
atol: strtol(nptr, (char **)NULL, 10)
- atoll: strtoll(nptr, (char **)NULL, 10)</pre>
+ atoll: strtoll(nptr, (char **)NULL, 10)
+</pre>
<h6>Returns</h6>
<p><!--para 3 -->
The atoi, atol, and atoll functions return the converted value.
float strtof(const char * restrict nptr,
char ** restrict endptr);
long double strtold(const char * restrict nptr,
- char ** restrict endptr);</pre>
+ char ** restrict endptr);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strtod, strtof, and strtold functions convert the initial portion of the string
digit
nondigit
n-char-sequence digit
- n-char-sequence nondigit</pre>
+ n-char-sequence nondigit
+</pre>
</ul>
The subject sequence is defined as the longest initial subsequence of the input string,
starting with the first non-white-space character, that is of the expected form. The subject
unsigned long long int strtoull(
const char * restrict nptr,
char ** restrict endptr,
- int base);</pre>
+ int base);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strtol, strtoll, strtoul, and strtoull functions convert the initial
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- int rand(void);</pre>
+ int rand(void);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The rand function computes a sequence of pseudo-random integers in the range 0 to
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- void srand(unsigned int seed);</pre>
+ void srand(unsigned int seed);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The srand function uses the argument as a seed for a new sequence of pseudo-random
void srand(unsigned int seed)
{
next = seed;
- }</pre>
+ }
+</pre>
<h4><a name="7.22.3" href="#7.22.3">7.22.3 Memory management functions</a></h4>
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- void *aligned_alloc(size_t alignment, size_t size);</pre>
+ void *aligned_alloc(size_t alignment, size_t size);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The aligned_alloc function allocates space for an object whose alignment is
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- void *calloc(size_t nmemb, size_t size);</pre>
+ void *calloc(size_t nmemb, size_t size);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The calloc function allocates space for an array of nmemb objects, each of whose size
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- void free(void *ptr);</pre>
+ void free(void *ptr);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The free function causes the space pointed to by ptr to be deallocated, that is, made
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- void *malloc(size_t size);</pre>
+ void *malloc(size_t size);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The malloc function allocates space for an object whose size is specified by size and
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- void *realloc(void *ptr, size_t size);</pre>
+ void *realloc(void *ptr, size_t size);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The realloc function deallocates the old object pointed to by ptr and returns a
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- _Noreturn void abort(void);</pre>
+ _Noreturn void abort(void);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The abort function causes abnormal program termination to occur, unless the signal
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- int atexit(void (*func)(void));</pre>
+ int atexit(void (*func)(void));
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The atexit function registers the function pointed to by func, to be called without
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- int at_quick_exit(void (*func)(void));</pre>
+ int at_quick_exit(void (*func)(void));
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The at_quick_exit function registers the function pointed to by func, to be called
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- _Noreturn void exit(int status);</pre>
+ _Noreturn void exit(int status);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The exit function causes normal program termination to occur. No functions registered
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- _Noreturn void _Exit(int status);</pre>
+ _Noreturn void _Exit(int status);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The _Exit function causes normal program termination to occur and control to be
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- char *getenv(const char *name);</pre>
+ char *getenv(const char *name);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The getenv function searches an environment list, provided by the host environment,
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- _Noreturn void quick_exit(int status);</pre>
+ _Noreturn void quick_exit(int status);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The quick_exit function causes normal program termination to occur. No functions
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- int system(const char *string);</pre>
+ int system(const char *string);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If string is a null pointer, the system function determines whether the host
<pre>
((char *)p - (char *)base) % size == 0
(char *)p >= (char *)base
- (char *)p < (char *)base + nmemb * size</pre>
+ (char *)p < (char *)base + nmemb * size
+</pre>
</small>
#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 *));</pre>
+ int (*compar)(const void *, const void *));
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The bsearch function searches an array of nmemb objects, the initial element of which
<pre>
#include <a href="#7.22"><stdlib.h></a>
void qsort(void *base, size_t nmemb, size_t size,
- int (*compar)(const void *, const void *));</pre>
+ int (*compar)(const void *, const void *));
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The qsort function sorts an array of nmemb objects, the initial element of which is
#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);</pre>
+ long long int llabs(long long int j);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The abs, labs, and llabs functions compute the absolute value of an integer j. If the
#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);</pre>
+ lldiv_t lldiv(long long int numer, long long int denom);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The div, ldiv, and lldiv, functions compute numer / denom and numer %
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- int mblen(const char *s, size_t n);</pre>
+ int mblen(const char *s, size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If s is not a null pointer, the mblen function determines the number of bytes contained
<!--page 375 -->
<pre>
mbtowc((wchar_t *)0, (const char *)0, 0);
- mbtowc((wchar_t *)0, s, n);</pre>
+ mbtowc((wchar_t *)0, s, n);
+</pre>
<p><!--para 3 -->
The implementation shall behave as if no library function calls the mblen function.
<h6>Returns</h6>
#include <a href="#7.22"><stdlib.h></a>
int mbtowc(wchar_t * restrict pwc,
const char * restrict s,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If s is not a null pointer, the mbtowc function inspects at most n bytes beginning with
<p><!--para 1 -->
<pre>
#include <a href="#7.22"><stdlib.h></a>
- int wctomb(char *s, wchar_t wc);</pre>
+ int wctomb(char *s, wchar_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wctomb function determines the number of bytes needed to represent the multibyte
#include <a href="#7.22"><stdlib.h></a>
size_t mbstowcs(wchar_t * restrict pwcs,
const char * restrict s,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The mbstowcs function converts a sequence of multibyte characters that begins in the
#include <a href="#7.22"><stdlib.h></a>
size_t wcstombs(char * restrict s,
const wchar_t * restrict pwcs,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcstombs function converts a sequence of wide characters from the array pointed
#include <a href="#7.23"><string.h></a>
void *memcpy(void * restrict s1,
const void * restrict s2,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The memcpy function copies n characters from the object pointed to by s2 into the
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- void *memmove(void *s1, const void *s2, size_t n);</pre>
+ void *memmove(void *s1, const void *s2, size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The memmove function copies n characters from the object pointed to by s2 into the
<pre>
#include <a href="#7.23"><string.h></a>
char *strcpy(char * restrict s1,
- const char * restrict s2);</pre>
+ const char * restrict s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strcpy function copies the string pointed to by s2 (including the terminating null
#include <a href="#7.23"><string.h></a>
char *strncpy(char * restrict s1,
const char * restrict s2,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strncpy function copies not more than n characters (characters that follow a null
<pre>
#include <a href="#7.23"><string.h></a>
char *strcat(char * restrict s1,
- const char * restrict s2);</pre>
+ const char * restrict s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strcat function appends a copy of the string pointed to by s2 (including the
#include <a href="#7.23"><string.h></a>
char *strncat(char * restrict s1,
const char * restrict s2,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strncat function appends not more than n characters (a null character and
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- int memcmp(const void *s1, const void *s2, size_t n);</pre>
+ int memcmp(const void *s1, const void *s2, size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The memcmp function compares the first n characters of the object pointed to by s1 to
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- int strcmp(const char *s1, const char *s2);</pre>
+ int strcmp(const char *s1, const char *s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strcmp function compares the string pointed to by s1 to the string pointed to by
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- int strcoll(const char *s1, const char *s2);</pre>
+ int strcoll(const char *s1, const char *s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strcoll function compares the string pointed to by s1 to the string pointed to by
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- int strncmp(const char *s1, const char *s2, size_t n);</pre>
+ int strncmp(const char *s1, const char *s2, size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strncmp function compares not more than n characters (characters that follow a
#include <a href="#7.23"><string.h></a>
size_t strxfrm(char * restrict s1,
const char * restrict s2,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strxfrm function transforms the string pointed to by s2 and places the resulting
EXAMPLE The value of the following expression is the size of the array needed to hold the
transformation of the string pointed to by s.
<pre>
- 1 + strxfrm(NULL, s, 0)</pre>
+ 1 + strxfrm(NULL, s, 0)
+</pre>
<h4><a name="7.23.5" href="#7.23.5">7.23.5 Search functions</a></h4>
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- void *memchr(const void *s, int c, size_t n);</pre>
+ void *memchr(const void *s, int c, size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The memchr function locates the first occurrence of c (converted to an unsigned
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- char *strchr(const char *s, int c);</pre>
+ char *strchr(const char *s, int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strchr function locates the first occurrence of c (converted to a char) in the
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- size_t strcspn(const char *s1, const char *s2);</pre>
+ size_t strcspn(const char *s1, const char *s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strcspn function computes the length of the maximum initial segment of the string
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- char *strpbrk(const char *s1, const char *s2);</pre>
+ char *strpbrk(const char *s1, const char *s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strpbrk function locates the first occurrence in the string pointed to by s1 of any
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- char *strrchr(const char *s, int c);</pre>
+ char *strrchr(const char *s, int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strrchr function locates the last occurrence of c (converted to a char) in the
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- size_t strspn(const char *s1, const char *s2);</pre>
+ size_t strspn(const char *s1, const char *s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strspn function computes the length of the maximum initial segment of the string
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- char *strstr(const char *s1, const char *s2);</pre>
+ char *strstr(const char *s1, const char *s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strstr function locates the first occurrence in the string pointed to by s1 of the
<pre>
#include <a href="#7.23"><string.h></a>
char *strtok(char * restrict s1,
- const char * restrict s2);</pre>
+ const char * restrict s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
A sequence of calls to the strtok function breaks the string pointed to by s1 into a
t = strtok(str, "?"); // t points to the token "a"
t = strtok(NULL, ","); // t points to the token "??b"
t = strtok(NULL, "#,"); // t points to the token "c"
- t = strtok(NULL, "?"); // t is a null pointer</pre>
+ t = strtok(NULL, "?"); // t is a null pointer
+</pre>
<h4><a name="7.23.6" href="#7.23.6">7.23.6 Miscellaneous functions</a></h4>
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- void *memset(void *s, int c, size_t n);</pre>
+ void *memset(void *s, int c, size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The memset function copies the value of c (converted to an unsigned char) into
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- char *strerror(int errnum);</pre>
+ char *strerror(int errnum);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strerror function maps the number in errnum to a message string. Typically,
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><string.h></a>
- size_t strlen(const char *s);</pre>
+ size_t strlen(const char *s);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strlen function computes the length of the string pointed to by s.
log clog log
pow cpow pow
sqrt csqrt sqrt
- fabs cabs fabs</pre>
+ fabs cabs fabs
+</pre>
If at least one argument for a generic parameter is complex, then use of the macro invokes
a complex function; otherwise, use of the macro invokes a real function.
<p><!--para 5 -->
exp2 ilogb lround tgamma
expm1 ldexp nearbyint trunc
fdim lgamma nextafter
- floor llrint nexttoward</pre>
+ floor llrint nexttoward
+</pre>
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.
<!--page 390 -->
function. These type-generic macros are:
<pre>
carg conj creal
- cimag cproj</pre>
+ cimag cproj
+</pre>
Use of the macro with any real or complex argument invokes a complex function.
<p><!--para 7 -->
EXAMPLE With the declarations
long double ld;
float complex fc;
double complex dc;
- long double complex ldc;</pre>
+ long double complex ldc;
+</pre>
functions invoked by use of type-generic macros are shown in the following table:
<!--page 391 -->
<pre>
cimag(ld) cimagl(ld)
fabs(fc) cabsf(fc)
carg(dc) carg(dc), the function
- cproj(ldc) cprojl(ldc)</pre>
+ cproj(ldc) cprojl(ldc)
+</pre>
<h6>footnotes</h6>
<p><small><a name="note304" href="#note304">304)</a> Like other function-like macros in Standard libraries, each type-generic macro can be suppressed to
<p><!--para 3 -->
The macros are
<pre>
- ONCE_FLAG_INIT</pre>
+ ONCE_FLAG_INIT
+</pre>
which expands to a value that can be used to initialize an object of type once_flag;
and
<pre>
- TSS_DTOR_ITERATIONS</pre>
+ TSS_DTOR_ITERATIONS
+</pre>
which expands to an integer constant expression representing the maximum number of
times that destructors will be called when a thread terminates.
<p><!--para 4 -->
The types are
<pre>
- cnd_t</pre>
+ cnd_t
+</pre>
which is a complete object type that holds an identifier for a condition variable;
<pre>
- thrd_t</pre>
+ thrd_t
+</pre>
which is a complete object type that holds an identifier for a thread;
<pre>
- tss_t</pre>
+ tss_t
+</pre>
which is a complete object type that holds an identifier for a thread-specific storage
pointer;
<pre>
- mtx_t</pre>
+ mtx_t
+</pre>
which is a complete object type that holds an identifier for a mutex;
<pre>
- tss_dtor_t</pre>
+ tss_dtor_t
+</pre>
which is the function pointer type void (*)(void*), used for a destructor for a
thread-specific storage pointer;
<pre>
- thrd_start_t</pre>
+ thrd_start_t
+</pre>
which is the function pointer type int (*)(void*) that is passed to thrd_create
to create a new thread;
<pre>
- once_flag</pre>
+ once_flag
+</pre>
which is a complete object type that holds a flag for use by call_once; and
<!--page 392 -->
<pre>
- xtime</pre>
+ xtime
+</pre>
which is a structure type that holds a time specified in seconds and nanoseconds. The
structure shall contain at least the following members, in any order.
<pre>
time_t sec;
- long nsec;</pre>
+ long nsec;
+</pre>
<p><!--para 5 -->
The enumeration constants are
<pre>
- mtx_plain</pre>
+ mtx_plain
+</pre>
which is passed to mtx_init to create a mutex object that supports neither timeout nor
test and return;
<pre>
- mtx_recursive</pre>
+ mtx_recursive
+</pre>
which is passed to mtx_init to create a mutex object that supports recursive locking;
<pre>
- mtx_timed</pre>
+ mtx_timed
+</pre>
which is passed to mtx_init to create a mutex object that supports timeout;
<pre>
- mtx_try</pre>
+ mtx_try
+</pre>
which is passed to mtx_init to create a mutex object that supports test and return;
<pre>
- thrd_timeout</pre>
+ thrd_timeout
+</pre>
which is returned by a timed wait function to indicate that the time specified in the call
was reached without acquiring the requested resource;
<pre>
- thrd_success</pre>
+ thrd_success
+</pre>
which is returned by a function to indicate that the requested operation succeeded;
<pre>
- thrd_busy</pre>
+ thrd_busy
+</pre>
which is returned by a function to indicate that the requested operation failed because a
resource requested by a test and return function is already in use;
<pre>
- thrd_error</pre>
+ thrd_error
+</pre>
which is returned by a function to indicate that the requested operation failed; and
<pre>
- thrd_nomem</pre>
+ thrd_nomem
+</pre>
which is returned by a function to indicate that the requested operation failed because it
was unable to allocate memory.
<!--page 393 -->
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- void call_once(once_flag *flag, void (*func)(void));</pre>
+ void call_once(once_flag *flag, void (*func)(void));
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The call_once function uses the once_flag pointed to by flag to ensure that
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int cnd_broadcast(cnd_t *cond);</pre>
+ int cnd_broadcast(cnd_t *cond);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cnd_broadcast function unblocks all of the threads that are blocked on the
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- void cnd_destroy(cnd_t *cond);</pre>
+ void cnd_destroy(cnd_t *cond);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cnd_destroy function releases all resources used by the condition variable
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int cnd_init(cnd_t *cond);</pre>
+ int cnd_init(cnd_t *cond);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cnd_init function creates a condition variable. If it succeeds it sets the variable
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int cnd_signal(cnd_t *cond);</pre>
+ int cnd_signal(cnd_t *cond);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cnd_signal function unblocks one of the threads that are blocked on the
<pre>
#include <a href="#7.25"><threads.h></a>
int cnd_timedwait(cnd_t *cond, mtx_t *mtx,
- const xtime *xt);</pre>
+ const xtime *xt);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cnd_timedwait function atomically unlocks the mutex pointed to by mtx and
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int cnd_wait(cnd_t *cond, mtx_t *mtx);</pre>
+ int cnd_wait(cnd_t *cond, mtx_t *mtx);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The cnd_wait function atomically unlocks the mutex pointed to by mtx and endeavors
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- void mtx_destroy(mtx_t *mtx);</pre>
+ void mtx_destroy(mtx_t *mtx);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The mtx_destroy function releases any resources used by the mutex pointed to by
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int mtx_init(mtx_t *mtx, int type);</pre>
+ int mtx_init(mtx_t *mtx, int type);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The mtx_init function creates a mutex object with properties indicated by type,
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int mtx_lock(mtx_t *mtx);</pre>
+ int mtx_lock(mtx_t *mtx);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The mtx_lock function blocks until it locks the mutex pointed to by mtx. If the mutex
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int mtx_timedlock(mtx_t *mtx, const xtime *xt);</pre>
+ int mtx_timedlock(mtx_t *mtx, const xtime *xt);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The mtx_timedlock function endeavors to block until it locks the mutex pointed to by
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int mtx_trylock(mtx_t *mtx);</pre>
+ int mtx_trylock(mtx_t *mtx);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The mtx_trylock function endeavors to lock the mutex pointed to by mtx. The
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int mtx_unlock(mtx_t *mtx);</pre>
+ int mtx_unlock(mtx_t *mtx);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The mtx_unlock function unlocks the mutex pointed to by mtx. The mutex pointed to
<pre>
#include <a href="#7.25"><threads.h></a>
int thrd_create(thrd_t *thr, thrd_start_t func,
- void *arg);</pre>
+ void *arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The thrd_create function creates a new thread executing func(arg). If the
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- thrd_t thrd_current(void);</pre>
+ thrd_t thrd_current(void);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The thrd_current function identifies the thread that called it.
<!--page 399 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int thrd_detach(thrd_t thr);</pre>
+ int thrd_detach(thrd_t thr);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The thrd_detach function tells the operating system to dispose of any resources
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int thrd_equal(thrd_t thr0, thrd_t thr1);</pre>
+ int thrd_equal(thrd_t thr0, thrd_t thr1);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The thrd_equal function will determine whether the thread identified by thr0 refers
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- void thrd_exit(int res);</pre>
+ void thrd_exit(int res);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The thrd_exit function terminates execution of the calling thread and sets its result
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int thrd_join(thrd_t thr, int *res);</pre>
+ int thrd_join(thrd_t thr, int *res);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The thrd_join function joins the thread identified by thr with the current thread by
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- void thrd_sleep(const xtime *xt);</pre>
+ void thrd_sleep(const xtime *xt);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The thrd_sleep function suspends execution of the calling thread until after the time
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- void thrd_yield(void);</pre>
+ void thrd_yield(void);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The thrd_yield function endeavors to permit other threads to run, even if the current
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int tss_create(tss_t *key, tss_dtor_t dtor);</pre>
+ int tss_create(tss_t *key, tss_dtor_t dtor);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The tss_create function creates a thread-specific storage pointer with destructor
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- void tss_delete(tss_t key);</pre>
+ void tss_delete(tss_t key);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The tss_delete function releases any resources used by the thread-specific storage
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- void *tss_get(tss_t key);</pre>
+ void *tss_get(tss_t key);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The tss_get function returns the value for the current thread held in the thread-specific
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int tss_set(tss_t key, void *val);</pre>
+ int tss_set(tss_t key, void *val);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The tss_set function sets the value for the current thread held in the thread-specific
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><threads.h></a>
- int xtime_get(xtime *xt, int base);</pre>
+ int xtime_get(xtime *xt, int base);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The xtime_get function sets the xtime object pointed to by xt to hold the current
<p><!--para 2 -->
The macros defined are NULL (described in <a href="#7.19">7.19</a>); and
<pre>
- CLOCKS_PER_SEC</pre>
+ CLOCKS_PER_SEC
+</pre>
which expands to an expression with type clock_t (described below) that is the
number per second of the value returned by the clock function.
<p><!--para 3 -->
The types declared are size_t (described in <a href="#7.19">7.19</a>);
<pre>
- clock_t</pre>
+ clock_t
+</pre>
and
<pre>
- time_t</pre>
+ time_t
+</pre>
which are arithmetic types capable of representing times; and
<pre>
- struct tm</pre>
+ struct tm
+</pre>
which holds the components of a calendar time, called the broken-down time.
<p><!--para 4 -->
The range and precision of times representable in clock_t and time_t are
int tm_year; // years since 1900
int tm_wday; // days since Sunday -- [0, 6]
int tm_yday; // days since January 1 -- [0, 365]
- int tm_isdst; // Daylight Saving Time flag</pre>
+ int tm_isdst; // Daylight Saving Time flag
+</pre>
<p><!--para 1 -->
<pre>
#include <a href="#7.26"><time.h></a>
- clock_t clock(void);</pre>
+ clock_t clock(void);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The clock function determines the processor time used.
<p><!--para 1 -->
<pre>
#include <a href="#7.26"><time.h></a>
- double difftime(time_t time1, time_t time0);</pre>
+ double difftime(time_t time1, time_t time0);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The difftime function computes the difference between two calendar times: time1 -
<p><!--para 1 -->
<pre>
#include <a href="#7.26"><time.h></a>
- time_t mktime(struct tm *timeptr);</pre>
+ time_t mktime(struct tm *timeptr);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The mktime function converts the broken-down time, expressed as local time, in the
"Thursday", "Friday", "Saturday", "-unknown-"
};
struct tm time_str;
- /* ... */</pre>
+ /* ... */
+</pre>
time_str.tm_isdst = -1;
if (mktime(&time_str) == (time_t)(-1))
time_str.tm_wday = 7;
- printf("%s\n", wday[time_str.tm_wday]);</pre>
+ printf("%s\n", wday[time_str.tm_wday]);
+</pre>
<h6>footnotes</h6>
<p><!--para 1 -->
<pre>
#include <a href="#7.26"><time.h></a>
- time_t time(time_t *timer);</pre>
+ time_t time(time_t *timer);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The time function determines the current calendar time. The encoding of the value is
<p><!--para 1 -->
<pre>
#include <a href="#7.26"><time.h></a>
- char *asctime(const struct tm *timeptr);</pre>
+ char *asctime(const struct tm *timeptr);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The asctime function converts the broken-down time in the structure pointed to by
timeptr into a string in the form
<!--page 407 -->
<pre>
- Sun Sep 16 01:03:52 1973\n\0</pre>
+ Sun Sep 16 01:03:52 1973\n\0
+</pre>
using the equivalent of the following algorithm.
char *asctime(const struct tm *timeptr)
{
timeptr->tm_mday, timeptr->tm_hour,
timeptr->tm_min, timeptr->tm_sec,
1900 + timeptr->tm_year);
- return result;</pre>
+ return result;
+</pre>
}
<p><!--para 3 -->
If any of the fields of the broken-down time contain values that are outside their normal
<p><!--para 1 -->
<pre>
#include <a href="#7.26"><time.h></a>
- char *ctime(const time_t *timer);</pre>
+ char *ctime(const time_t *timer);
+</pre>
<h6>Description</h6>
<p><!--para 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
<pre>
- asctime(localtime(timer))</pre>
+ asctime(localtime(timer))
+</pre>
<p><!--para 1 -->
<pre>
#include <a href="#7.26"><time.h></a>
- struct tm *gmtime(const time_t *timer);</pre>
+ struct tm *gmtime(const time_t *timer);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The gmtime function converts the calendar time pointed to by timer into a broken-
<p><!--para 1 -->
<pre>
#include <a href="#7.26"><time.h></a>
- struct tm *localtime(const time_t *timer);</pre>
+ struct tm *localtime(const time_t *timer);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The localtime function converts the calendar time pointed to by timer into a
size_t strftime(char * restrict s,
size_t maxsize,
const char * restrict format,
- const struct tm * restrict timeptr);</pre>
+ const struct tm * restrict timeptr);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strftime function places characters into the array pointed to by s as controlled by
%B is replaced by the locale's full month name. [tm_mon]
%c is replaced by the locale's appropriate date and time representation. [all specified
<pre>
- in <a href="#7.26.1">7.26.1</a>]</pre>
+ in <a href="#7.26.1">7.26.1</a>]
+</pre>
%C is replaced by the year divided by 100 and truncated to an integer, as a decimal
<pre>
- number (00-99). [tm_year]</pre>
+ number (00-99). [tm_year]
+</pre>
%d is replaced by the day of the month as a decimal number (01-31). [tm_mday]
%D is equivalent to ''%m/%d/%y''. [tm_mon, tm_mday, tm_year]
%e is replaced by the day of the month as a decimal number (1-31); a single digit is
<pre>
- preceded by a space. [tm_mday]</pre>
+ preceded by a space. [tm_mday]
+</pre>
%F is equivalent to ''%Y-%m-%d'' (the ISO 8601 date format). [tm_year, tm_mon,
<pre>
- tm_mday]</pre>
+ tm_mday]
+</pre>
%g is replaced by the last 2 digits of the week-based year (see below) as a decimal
<pre>
- number (00-99). [tm_year, tm_wday, tm_yday]</pre>
+ number (00-99). [tm_year, tm_wday, tm_yday]
+</pre>
%G is replaced by the week-based year (see below) as a decimal number (e.g., 1997).
<pre>
- [tm_year, tm_wday, tm_yday]</pre>
+ [tm_year, tm_wday, tm_yday]
+</pre>
%h is equivalent to ''%b''. [tm_mon]
%H is replaced by the hour (24-hour clock) as a decimal number (00-23). [tm_hour]
%I is replaced by the hour (12-hour clock) as a decimal number (01-12). [tm_hour]
<!--page 410 -->
%p is replaced by the locale's equivalent of the AM/PM designations associated with a
<pre>
- 12-hour clock. [tm_hour]</pre>
+ 12-hour clock. [tm_hour]
+</pre>
%r is replaced by the locale's 12-hour clock time. [tm_hour, tm_min, tm_sec]
%R is equivalent to ''%H:%M''. [tm_hour, tm_min]
%S is replaced by the second as a decimal number (00-60). [tm_sec]
%t is replaced by a horizontal-tab character.
%T is equivalent to ''%H:%M:%S'' (the ISO 8601 time format). [tm_hour, tm_min,
<pre>
- tm_sec]</pre>
+ tm_sec]
+</pre>
%u is replaced by the ISO 8601 weekday as a decimal number (1-7), where Monday
<pre>
- is 1. [tm_wday]</pre>
+ is 1. [tm_wday]
+</pre>
%U is replaced by the week number of the year (the first Sunday as the first day of week
<pre>
- 1) as a decimal number (00-53). [tm_year, tm_wday, tm_yday]</pre>
+ 1) as a decimal number (00-53). [tm_year, tm_wday, tm_yday]
+</pre>
%V is replaced by the ISO 8601 week number (see below) as a decimal number
<pre>
- (01-53). [tm_year, tm_wday, tm_yday]</pre>
+ (01-53). [tm_year, tm_wday, tm_yday]
+</pre>
%w is replaced by the weekday as a decimal number (0-6), where Sunday is 0.
<pre>
- [tm_wday]</pre>
+ [tm_wday]
+</pre>
%W is replaced by the week number of the year (the first Monday as the first day of
<pre>
- week 1) as a decimal number (00-53). [tm_year, tm_wday, tm_yday]</pre>
+ week 1) as a decimal number (00-53). [tm_year, tm_wday, tm_yday]
+</pre>
%x is replaced by the locale's appropriate date representation. [all specified in <a href="#7.26.1">7.26.1</a>]
%X is replaced by the locale's appropriate time representation. [all specified in <a href="#7.26.1">7.26.1</a>]
%y is replaced by the last 2 digits of the year as a decimal number (00-99).
<pre>
- [tm_year]</pre>
+ [tm_year]
+</pre>
%Y is replaced by the year as a decimal number (e.g., 1997). [tm_year]
%z is replaced by the offset from UTC in the ISO 8601 format ''-0430'' (meaning 4
<pre>
hours 30 minutes behind UTC, west of Greenwich), or by no characters if no time
- zone is determinable. [tm_isdst]</pre>
+ zone is determinable. [tm_isdst]
+</pre>
%Z is replaced by the locale's time zone name or abbreviation, or by no characters if no
<pre>
- time zone is determinable. [tm_isdst]</pre>
+ time zone is determinable. [tm_isdst]
+</pre>
%% is replaced by %.
<p><!--para 4 -->
Some conversion specifiers can be modified by the inclusion of an E or O modifier
%Ec is replaced by the locale's alternative date and time representation.
%EC is replaced by the name of the base year (period) in the locale's alternative
<pre>
- representation.</pre>
+ representation.
+</pre>
%Ex is replaced by the locale's alternative date representation.
%EX is replaced by the locale's alternative time representation.
%Ey is replaced by the offset from %EC (year only) in the locale's alternative
<pre>
- representation.</pre>
+ representation.
+</pre>
%EY is replaced by the locale's full alternative year representation.
<!--page 411 -->
%Od is replaced by the day of the month, using the locale's alternative numeric symbols
<pre>
(filled as needed with leading zeros, or with leading spaces if there is no alternative
- symbol for zero).</pre>
+ symbol for zero).
+</pre>
%Oe is replaced by the day of the month, using the locale's alternative numeric symbols
<pre>
- (filled as needed with leading spaces).</pre>
+ (filled as needed with leading spaces).
+</pre>
%OH is replaced by the hour (24-hour clock), using the locale's alternative numeric
<pre>
- symbols.</pre>
+ symbols.
+</pre>
%OI is replaced by the hour (12-hour clock), using the locale's alternative numeric
<pre>
- symbols.</pre>
+ symbols.
+</pre>
%Om is replaced by the month, using the locale's alternative numeric symbols.
%OM is replaced by the minutes, using the locale's alternative numeric symbols.
%OS is replaced by the seconds, using the locale's alternative numeric symbols.
%Ou is replaced by the ISO 8601 weekday as a number in the locale's alternative
<pre>
- representation, where Monday is 1.</pre>
+ representation, where Monday is 1.
+</pre>
%OU is replaced by the week number, using the locale's alternative numeric symbols.
%OV is replaced by the ISO 8601 week number, using the locale's alternative numeric
<pre>
- symbols.</pre>
+ symbols.
+</pre>
%Ow is replaced by the weekday as a number, using the locale's alternative numeric
<pre>
- symbols.</pre>
+ symbols.
+</pre>
%OW is replaced by the week number of the year, using the locale's alternative numeric
<pre>
- symbols.</pre>
+ symbols.
+</pre>
%Oy is replaced by the last 2 digits of the year, using the locale's alternative numeric
<pre>
- symbols.</pre>
+ symbols.
+</pre>
<p><!--para 5 -->
%g, %G, and %V give values according to the ISO 8601 week-based year. In this system,
weeks begin on a Monday and week 1 of the year is the week that includes January 4th,
The types declared are mbstate_t (described in <a href="#7.29.1">7.29.1</a>) and size_t (described in
<a href="#7.19">7.19</a>);
<pre>
- char16_t</pre>
+ char16_t
+</pre>
which is an unsigned integer type used for 16-bit characters and is the same type as
uint_least16_t (described in <a href="#7.20.1.2">7.20.1.2</a>); and
<pre>
- char32_t</pre>
+ char32_t
+</pre>
which is an unsigned integer type used for 32-bit characters and is the same type as
uint_least32_t (also described in <a href="#7.20.1.2">7.20.1.2</a>).
#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);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If s is a null pointer, the mbrtoc16 function is equivalent to the call:
<pre>
- mbrtoc16(NULL, "", 1, ps)</pre>
+ mbrtoc16(NULL, "", 1, ps)
+</pre>
In this case, the values of the parameters pc16 and n are ignored.
<p><!--para 3 -->
If s is not a null pointer, the mbrtoc16 function inspects at most n bytes beginning with
conversion state):
0 if the next n or fewer bytes complete the multibyte character that
<pre>
- corresponds to the null wide character (which is the value stored).</pre>
+ corresponds to the null wide character (which is the value stored).
+</pre>
between 1 and n inclusive if the next n or fewer bytes complete a valid multibyte
<pre>
character (which is the value stored); the value returned is the number
- of bytes that complete the multibyte character.</pre>
+ of bytes that complete the multibyte character.
+</pre>
(size_t)(-3) if the next character resulting from a previous call has been stored (no
<pre>
- bytes from the input have been consumed by this call).</pre>
+ bytes from the input have been consumed by this call).
+</pre>
(size_t)(-2) if the next n bytes contribute to an incomplete (but potentially valid)
<pre>
multibyte character, and all n bytes have been processed (no value is
- stored).<sup><a href="#note311"><b>311)</b></a></sup></pre>
+ stored).<sup><a href="#note311"><b>311)</b></a></sup>
+</pre>
(size_t)(-1) if an encoding error occurs, in which case the next n or fewer bytes
<pre>
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.</pre>
+ and the conversion state is unspecified.
+</pre>
<h6>footnotes</h6>
<p><small><a name="note311" href="#note311">311)</a> When n has at least the value of the MB_CUR_MAX macro, this case can only occur if s points at a
<pre>
#include <a href="#7.27"><uchar.h></a>
size_t c16rtomb(char * restrict s, char16_t c16,
- mbstate_t * restrict ps);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If s is a null pointer, the c16rtomb function is equivalent to the call
<pre>
- c16rtomb(buf, L'\0', ps)</pre>
+ c16rtomb(buf, L'\0', ps)
+</pre>
where buf is an internal buffer.
<p><!--para 3 -->
If s is not a null pointer, the c16rtomb function determines the number of bytes needed
#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);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If s is a null pointer, the mbrtoc32 function is equivalent to the call:
<pre>
- mbrtoc32(NULL, "", 1, ps)</pre>
+ mbrtoc32(NULL, "", 1, ps)
+</pre>
In this case, the values of the parameters pc32 and n are ignored.
<p><!--para 3 -->
If s is not a null pointer, the mbrtoc32 function inspects at most n bytes beginning with
conversion state):
0 if the next n or fewer bytes complete the multibyte character that
<pre>
- corresponds to the null wide character (which is the value stored).</pre>
+ corresponds to the null wide character (which is the value stored).
+</pre>
between 1 and n inclusive if the next n or fewer bytes complete a valid multibyte
<!--page 416 -->
<pre>
character (which is the value stored); the value returned is the number
- of bytes that complete the multibyte character.</pre>
+ of bytes that complete the multibyte character.
+</pre>
(size_t)(-3) if the next character resulting from a previous call has been stored (no
<pre>
- bytes from the input have been consumed by this call).</pre>
+ bytes from the input have been consumed by this call).
+</pre>
(size_t)(-2) if the next n bytes contribute to an incomplete (but potentially valid)
<pre>
multibyte character, and all n bytes have been processed (no value is
- stored).<sup><a href="#note312"><b>312)</b></a></sup></pre>
+ stored).<sup><a href="#note312"><b>312)</b></a></sup>
+</pre>
(size_t)(-1) if an encoding error occurs, in which case the next n or fewer bytes
<pre>
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.</pre>
+ and the conversion state is unspecified.
+</pre>
<h6>footnotes</h6>
<p><small><a name="note312" href="#note312">312)</a> When n has at least the value of the MB_CUR_MAX macro, this case can only occur if s points at a
<pre>
#include <a href="#7.27"><uchar.h></a>
size_t c32rtomb(char * restrict s, char32_t c32,
- mbstate_t * restrict ps);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If s is a null pointer, the c32rtomb function is equivalent to the call
<pre>
- c32rtomb(buf, L'\0', ps)</pre>
+ c32rtomb(buf, L'\0', ps)
+</pre>
where buf is an internal buffer.
<p><!--para 3 -->
If s is not a null pointer, the c32rtomb function determines the number of bytes needed
<p><!--para 2 -->
The types declared are wchar_t and size_t (both described in <a href="#7.19">7.19</a>);
<pre>
- mbstate_t</pre>
+ mbstate_t
+</pre>
which is a complete object type other than an array type that can hold the conversion state
information necessary to convert between sequences of multibyte characters and wide
characters;
<pre>
- wint_t</pre>
+ wint_t
+</pre>
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);<sup><a href="#note314"><b>314)</b></a></sup> and
<pre>
- struct tm</pre>
+ struct tm
+</pre>
which is declared as an incomplete structure type (the contents are described in <a href="#7.26.1">7.26.1</a>).
<p><!--para 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
<pre>
- WEOF</pre>
+ WEOF
+</pre>
which expands to a constant expression of type wint_t whose value does not
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
#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, ...);</pre>
+ const wchar_t * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fwprintf function writes output to the stream pointed to by stream, under
The flag wide characters and their meanings are:
- The result of the conversion is left-justified within the field. (It is right-justified if
<pre>
- this flag is not specified.)</pre>
+ this flag is not specified.)
+</pre>
+ The result of a signed conversion always begins with a plus or minus sign. (It
<pre>
begins with a sign only when a negative value is converted if this flag is not
- specified.)<sup><a href="#note318"><b>318)</b></a></sup></pre>
+ specified.)<sup><a href="#note318"><b>318)</b></a></sup>
+</pre>
space If the first wide character of a signed conversion is not a sign, or if a signed
<pre>
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.</pre>
+ space and + flags both appear, the space flag is ignored.
+</pre>
# The result is converted to an ''alternative form''. For o conversion, it increases
<pre>
the precision, if and only if necessary, to force the first digit of the result to be a
zero (if the value and precision are both 0, a single 0 is printed). For x (or X)
- conversion, a nonzero result has 0x (or 0X) prefixed to it. For a, A, e, E, f, F, g,</pre>
+ conversion, a nonzero result has 0x (or 0X) prefixed to it. For a, A, e, E, f, F, g,
+</pre>
<!--page 420 -->
contains a decimal-point wide character, even if no digits follow it. (Normally, a
decimal-point wide character appears in the result of these conversions only if a
digit follows it.) For g and G conversions, trailing zeros are not removed from the
- result. For other conversions, the behavior is undefined.</pre>
+ result. For other conversions, the behavior is undefined.
+</pre>
0 For d, i, o, u, x, X, a, A, e, E, f, F, g, and G conversions, leading zeros
<pre>
(following any indication of sign or base) are used to pad to the field width rather
than performing space padding, except when converting an infinity or NaN. If the
0 and - flags both appear, the 0 flag is ignored. For d, i, o, u, x, and X
conversions, if a precision is specified, the 0 flag is ignored. For other
- conversions, the behavior is undefined.</pre>
+ conversions, the behavior is undefined.
+</pre>
<p><!--para 7 -->
The length modifiers and their meanings are:
hh Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
been promoted according to the integer promotions, but its value shall be
converted to signed char or unsigned char before printing); or that
a following n conversion specifier applies to a pointer to a signed char
- argument.</pre>
+ argument.
+</pre>
h Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
<pre>
short int or unsigned short int argument (the argument will
have been promoted according to the integer promotions, but its value shall
be converted to short int or unsigned short int before printing);
or that a following n conversion specifier applies to a pointer to a short
- int argument.</pre>
+ int argument.
+</pre>
l (ell) Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
<pre>
long int or unsigned long int argument; that a following n
following c conversion specifier applies to a wint_t argument; that a
following s conversion specifier applies to a pointer to a wchar_t
argument; or has no effect on a following a, A, e, E, f, F, g, or G conversion
- specifier.</pre>
+ specifier.
+</pre>
ll (ell-ell) Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
<pre>
long long int or unsigned long long int argument; or that a
following n conversion specifier applies to a pointer to a long long int
- argument.</pre>
+ argument.
+</pre>
j Specifies that a following d, i, o, u, x, or X conversion specifier applies to
<!--page 421 -->
<pre>
an intmax_t or uintmax_t argument; or that a following n conversion
- specifier applies to a pointer to an intmax_t argument.</pre>
+ specifier applies to a pointer to an intmax_t argument.
+</pre>
z Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
<pre>
size_t or the corresponding signed integer type argument; or that a
following n conversion specifier applies to a pointer to a signed integer type
- corresponding to size_t argument.</pre>
+ corresponding to size_t argument.
+</pre>
t Specifies that a following d, i, o, u, x, or X conversion specifier applies to a
<pre>
ptrdiff_t or the corresponding unsigned integer type argument; or that a
following n conversion specifier applies to a pointer to a ptrdiff_t
- argument.</pre>
+ argument.
+</pre>
L Specifies that a following a, A, e, E, f, F, g, or G conversion specifier
<pre>
- applies to a long double argument.</pre>
+ applies to a long double argument.
+</pre>
If a length modifier appears with any conversion specifier other than as specified above,
the behavior is undefined.
<p><!--para 8 -->
precision specifies the minimum number of digits to appear; if the value
being converted can be represented in fewer digits, it is expanded with
leading zeros. The default precision is 1. The result of converting a zero
- value with a precision of zero is no wide characters.</pre>
+ value with a precision of zero is no wide characters.
+</pre>
o,u,x,X The unsigned int argument is converted to unsigned octal (o), unsigned
<pre>
decimal (u), or unsigned hexadecimal notation (x or X) in the style dddd; the
conversion. The precision specifies the minimum number of digits to appear;
if the value being converted can be represented in fewer digits, it is expanded
with leading zeros. The default precision is 1. The result of converting a
- zero value with a precision of zero is no wide characters.</pre>
+ zero value with a precision of zero is no wide characters.
+</pre>
f,F A double argument representing a floating-point number is converted to
<!--page 422 -->
<pre>
[-]nan or [-]nan(n-wchar-sequence) -- which style, and the meaning of
any n-wchar-sequence, is implementation-defined. The F conversion
specifier produces INF, INFINITY, or NAN instead of inf, infinity, or
- nan, respectively.<sup><a href="#note319"><b>319)</b></a></sup></pre>
+ nan, respectively.<sup><a href="#note319"><b>319)</b></a></sup>
+</pre>
e,E A double argument representing a floating-point number is converted in the
<pre>
style [-]d.ddd e(+-)dd, where there is one digit (which is nonzero if the
and only as many more digits as necessary to represent the exponent. If the
value is zero, the exponent is zero.
A double argument representing an infinity or NaN is converted in the style
- of an f or F conversion specifier.</pre>
+ of an f or F conversion specifier.
+</pre>
g,G A double argument representing a floating-point number is converted in
<pre>
style f or e (or in style F or E in the case of a G conversion specifier),
fractional portion of the result and the decimal-point wide character is
removed if there is no fractional portion remaining.
A double argument representing an infinity or NaN is converted in the style
- of an f or F conversion specifier.</pre>
+ of an f or F conversion specifier.
+</pre>
a,A A double argument representing a floating-point number is converted in the
<pre>
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 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</pre>
+ is missing and FLT_RADIX is a power of 2, then the precision is sufficient
+</pre>
<!--page 423 -->
represent the decimal exponent of 2. If the value is zero, the exponent is
zero.
A double argument representing an infinity or NaN is converted in the style
- of an f or F conversion specifier.</pre>
+ of an f or F conversion specifier.
+</pre>
c If no l length modifier is present, the int argument is converted to a wide
<pre>
character as if by calling btowc and the resulting wide character is written.
If an l length modifier is present, the wint_t argument is converted to
- wchar_t and written.</pre>
+ wchar_t and written.
+</pre>
s If no l length modifier is present, the argument shall be a pointer to the initial
<pre>
element of a character array containing a multibyte character sequence
written up to (but not including) a terminating null wide character. If the
precision is specified, no more than that many wide characters are written. If
the precision is not specified or is greater than the size of the array, the array
- shall contain a null wide character.</pre>
+ shall contain a null wide character.
+</pre>
p The argument shall be a pointer to void. The value of the pointer is
<pre>
- converted to a sequence of printing wide characters, in an implementation-</pre>
+ converted to a sequence of printing wide characters, in an implementation-
+</pre>
<!--page 424 -->
<pre>
- defined manner.</pre>
+ defined manner.
+</pre>
n The argument shall be a pointer to signed integer into which is written the
<pre>
number of wide characters written to the output stream so far by this call to
fwprintf. No argument is converted, but one is consumed. If the
conversion specification includes any flags, a field width, or a precision, the
- behavior is undefined.</pre>
+ behavior is undefined.
+</pre>
% A % wide character is written. No argument is converted. The complete
<pre>
- conversion specification shall be %%.</pre>
+ conversion specification shall be %%.
+</pre>
<p><!--para 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
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(1.0));</pre>
+ fwprintf(stdout, L"pi = %.5f\n", 4 * atan(1.0));
+</pre>
<p><b> Forward references</b>: 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>).
#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, ...);</pre>
+ const wchar_t * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fwscanf function reads input from the stream pointed to by stream, under
The length modifiers and their meanings are:
hh Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
- to an argument with type pointer to signed char or unsigned char.</pre>
+ to an argument with type pointer to signed char or unsigned char.
+</pre>
h Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
to an argument with type pointer to short int or unsigned short
- int.</pre>
+ int.
+</pre>
l (ell) Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
to an argument with type pointer to long int or unsigned long
int; that a following a, A, e, E, f, F, g, or G conversion specifier applies to
an argument with type pointer to double; or that a following c, s, or [
- conversion specifier applies to an argument with type pointer to wchar_t.</pre>
+ conversion specifier applies to an argument with type pointer to wchar_t.
+</pre>
ll (ell-ell) Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
to an argument with type pointer to long long int or unsigned
- long long int.</pre>
+ long long int.
+</pre>
j Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
- to an argument with type pointer to intmax_t or uintmax_t.</pre>
+ to an argument with type pointer to intmax_t or uintmax_t.
+</pre>
z Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
to an argument with type pointer to size_t or the corresponding signed
- integer type.</pre>
+ integer type.
+</pre>
t Specifies that a following d, i, o, u, x, X, or n conversion specifier applies
<pre>
to an argument with type pointer to ptrdiff_t or the corresponding
- unsigned integer type.</pre>
+ unsigned integer type.
+</pre>
L Specifies that a following a, A, e, E, f, F, g, or G conversion specifier
<pre>
- applies to an argument with type pointer to long double.</pre>
+ applies to an argument with type pointer to long double.
+</pre>
If a length modifier appears with any conversion specifier other than as specified above,
the behavior is undefined.
<p><!--para 12 -->
<pre>
expected for the subject sequence of the wcstol function with the value 10
for the base argument. The corresponding argument shall be a pointer to
- signed integer.</pre>
+ signed integer.
+</pre>
i Matches an optionally signed integer, whose format is the same as expected
<!--page 428 -->
<pre>
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
- integer.</pre>
+ integer.
+</pre>
o Matches an optionally signed octal integer, whose format is the same as
<pre>
expected for the subject sequence of the wcstoul function with the value 8
for the base argument. The corresponding argument shall be a pointer to
- unsigned integer.</pre>
+ unsigned integer.
+</pre>
u Matches an optionally signed decimal integer, whose format is the same as
<pre>
expected for the subject sequence of the wcstoul function with the value 10
for the base argument. The corresponding argument shall be a pointer to
- unsigned integer.</pre>
+ unsigned integer.
+</pre>
x Matches an optionally signed hexadecimal integer, whose format is the same
<pre>
as expected for the subject sequence of the wcstoul function with the value
16 for the base argument. The corresponding argument shall be a pointer to
- unsigned integer.</pre>
+ unsigned integer.
+</pre>
a,e,f,g Matches an optionally signed floating-point number, infinity, or NaN, whose
<pre>
format is the same as expected for the subject sequence of the wcstod
- function. The corresponding argument shall be a pointer to floating.</pre>
+ function. The corresponding argument shall be a pointer to floating.
+</pre>
c Matches a sequence of wide characters of exactly the number specified by the
<pre>
field width (1 if no field width is present in the directive).
accept the sequence. No null character is added.
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
- the sequence. No null wide character is added.</pre>
+ the sequence. No null wide character is added.
+</pre>
s Matches a sequence of non-white-space wide characters.
<!--page 429 -->
<pre>
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
the sequence and the terminating null wide character, which will be added
- automatically.</pre>
+ automatically.
+</pre>
[ Matches a nonempty sequence of wide characters from a set of expected
<pre>
characters (the scanset).
the specification; otherwise the first following right bracket wide character is
the one that ends the specification. If a - wide character is in the scanlist and
is not the first, nor the second where the first wide character is a ^, nor the
- last character, the behavior is implementation-defined.</pre>
+ last character, the behavior is implementation-defined.
+</pre>
p Matches an implementation-defined set of sequences, which should be the
<pre>
same as the set of sequences that may be produced by the %p conversion of
pointer to void. The input item is converted to a pointer value in an
implementation-defined manner. If the input item is a value converted earlier
during the same program execution, the pointer that results shall compare
- equal to that value; otherwise the behavior of the %p conversion is undefined.</pre>
+ equal to that value; otherwise the behavior of the %p conversion is undefined.
+</pre>
n No input is consumed. The corresponding argument shall be a pointer to
<!--page 430 -->
<pre>
completion of execution of the fwscanf function. No argument is
converted, but one is consumed. If the conversion specification includes an
assignment-suppressing wide character or a field width, the behavior is
- undefined.</pre>
+ undefined.
+</pre>
% Matches a single % wide character; no conversion or assignment occurs. The
<pre>
- complete conversion specification shall be %%.</pre>
+ complete conversion specification shall be %%.
+</pre>
<p><!--para 13 -->
If a conversion specification is invalid, the behavior is undefined.<sup><a href="#note326"><b>326)</b></a></sup>
<p><!--para 14 -->
#include <a href="#7.28"><wchar.h></a>
/* ... */
int n, i; float x; wchar_t name[50];
- n = fwscanf(stdin, L"%d%f%ls", &i, &x, name);</pre>
+ n = fwscanf(stdin, L"%d%f%ls", &i, &x, name);
+</pre>
with the input line:
<pre>
- 25 54.32E-1 thompson</pre>
+ 25 54.32E-1 thompson
+</pre>
will assign to n the value 3, to i the value 25, to x the value 5.432, and to name the sequence
thompson\0.
#include <a href="#7.28"><wchar.h></a>
/* ... */
int i; float x; double y;
- fwscanf(stdin, L"%2d%f%*d %lf", &i, &x, &y);</pre>
+ fwscanf(stdin, L"%2d%f%*d %lf", &i, &x, &y);
+</pre>
with input:
<pre>
- 56789 0123 56a72</pre>
+ 56789 0123 56a72
+</pre>
will assign to i the value 56 and to x the value 789.0, will skip past 0123, and will assign to y the value
56.0. The next wide character read from the input stream will be a.
#include <a href="#7.28"><wchar.h></a>
int swprintf(wchar_t * restrict s,
size_t n,
- const wchar_t * restrict format, ...);</pre>
+ const wchar_t * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The swprintf function is equivalent to fwprintf, except that the argument s
<pre>
#include <a href="#7.28"><wchar.h></a>
int swscanf(const wchar_t * restrict s,
- const wchar_t * restrict format, ...);</pre>
+ const wchar_t * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The swscanf function is equivalent to fwscanf, except that the argument s specifies a
#include <a href="#7.28"><wchar.h></a>
int vfwprintf(FILE * restrict stream,
const wchar_t * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vfwprintf function is equivalent to fwprintf, with the variable argument list
// print out remainder of message
vfwprintf(stderr, format, args);
va_end(args);
- }</pre>
+ }
+</pre>
#include <a href="#7.28"><wchar.h></a>
int vfwscanf(FILE * restrict stream,
const wchar_t * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vfwscanf function is equivalent to fwscanf, with the variable argument list
int vswprintf(wchar_t * restrict s,
size_t n,
const wchar_t * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vswprintf function is equivalent to swprintf, with the variable argument list
#include <a href="#7.28"><wchar.h></a>
int vswscanf(const wchar_t * restrict s,
const wchar_t * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vswscanf function is equivalent to swscanf, with the variable argument list
#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);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vwprintf function is equivalent to wprintf, with the variable argument list
#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);</pre>
+ va_list arg);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The vwscanf function is equivalent to wscanf, with the variable argument list
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- int wprintf(const wchar_t * restrict format, ...);</pre>
+ int wprintf(const wchar_t * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wprintf function is equivalent to fwprintf with the argument stdout
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- int wscanf(const wchar_t * restrict format, ...);</pre>
+ int wscanf(const wchar_t * restrict format, ...);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wscanf function is equivalent to fwscanf with the argument stdin interposed
<pre>
#include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
- wint_t fgetwc(FILE *stream);</pre>
+ wint_t fgetwc(FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If the end-of-file indicator for the input stream pointed to by stream is not set and a
#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);</pre>
+ int n, FILE * restrict stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fgetws function reads at most one less than the number of wide characters
<pre>
#include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
- wint_t fputwc(wchar_t c, FILE *stream);</pre>
+ wint_t fputwc(wchar_t c, FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fputwc function writes the wide character specified by c to the output stream
#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);</pre>
+ FILE * restrict stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fputws function writes the wide string pointed to by s to the stream pointed to by
<pre>
#include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
- int fwide(FILE *stream, int mode);</pre>
+ int fwide(FILE *stream, int mode);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The fwide function determines the orientation of the stream pointed to by stream. If
<pre>
#include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
- wint_t getwc(FILE *stream);</pre>
+ wint_t getwc(FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The getwc function is equivalent to fgetwc, except that if it is implemented as a
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- wint_t getwchar(void);</pre>
+ wint_t getwchar(void);
+</pre>
<pre>
#include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
- wint_t putwc(wchar_t c, FILE *stream);</pre>
+ wint_t putwc(wchar_t c, FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The putwc function is equivalent to fputwc, except that if it is implemented as a
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- wint_t putwchar(wchar_t c);</pre>
+ wint_t putwchar(wchar_t c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The putwchar function is equivalent to putwc with the second argument stdout.
<pre>
#include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
- wint_t ungetwc(wint_t c, FILE *stream);</pre>
+ wint_t ungetwc(wint_t c, FILE *stream);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The ungetwc function pushes the wide character specified by c back onto the input
float wcstof(const wchar_t * restrict nptr,
wchar_t ** restrict endptr);
long double wcstold(const wchar_t * restrict nptr,
- wchar_t ** restrict endptr);</pre>
+ wchar_t ** restrict endptr);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcstod, wcstof, and wcstold functions convert the initial portion of the wide
digit
nondigit
n-wchar-sequence digit
- n-wchar-sequence nondigit</pre>
+ n-wchar-sequence nondigit
+</pre>
</ul>
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.
unsigned long long int wcstoull(
const wchar_t * restrict nptr,
wchar_t ** restrict endptr,
- int base);</pre>
+ int base);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcstol, wcstoll, wcstoul, and wcstoull functions convert the initial
<pre>
#include <a href="#7.28"><wchar.h></a>
wchar_t *wcscpy(wchar_t * restrict s1,
- const wchar_t * restrict s2);</pre>
+ const wchar_t * restrict s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcscpy function copies the wide string pointed to by s2 (including the terminating
#include <a href="#7.28"><wchar.h></a>
wchar_t *wcsncpy(wchar_t * restrict s1,
const wchar_t * restrict s2,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcsncpy function copies not more than n wide characters (those that follow a null
#include <a href="#7.28"><wchar.h></a>
wchar_t *wmemcpy(wchar_t * restrict s1,
const wchar_t * restrict s2,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wmemcpy function copies n wide characters from the object pointed to by s2 to the
<pre>
#include <a href="#7.28"><wchar.h></a>
wchar_t *wmemmove(wchar_t *s1, const wchar_t *s2,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wmemmove function copies n wide characters from the object pointed to by s2 to
<pre>
#include <a href="#7.28"><wchar.h></a>
wchar_t *wcscat(wchar_t * restrict s1,
- const wchar_t * restrict s2);</pre>
+ const wchar_t * restrict s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcscat function appends a copy of the wide string pointed to by s2 (including the
#include <a href="#7.28"><wchar.h></a>
wchar_t *wcsncat(wchar_t * restrict s1,
const wchar_t * restrict s2,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcsncat function appends not more than n wide characters (a null wide character
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- int wcscmp(const wchar_t *s1, const wchar_t *s2);</pre>
+ int wcscmp(const wchar_t *s1, const wchar_t *s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcscmp function compares the wide string pointed to by s1 to the wide string
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- int wcscoll(const wchar_t *s1, const wchar_t *s2);</pre>
+ int wcscoll(const wchar_t *s1, const wchar_t *s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcscoll function compares the wide string pointed to by s1 to the wide string
<pre>
#include <a href="#7.28"><wchar.h></a>
int wcsncmp(const wchar_t *s1, const wchar_t *s2,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcsncmp function compares not more than n wide characters (those that follow a
#include <a href="#7.28"><wchar.h></a>
size_t wcsxfrm(wchar_t * restrict s1,
const wchar_t * restrict s2,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcsxfrm function transforms the wide string pointed to by s2 and places the
transformation of the wide string pointed to by s:
<!--page 450 -->
<pre>
- 1 + wcsxfrm(NULL, s, 0)</pre>
+ 1 + wcsxfrm(NULL, s, 0)
+</pre>
<h5><a name="7.28.4.4.5" href="#7.28.4.4.5">7.28.4.4.5 The wmemcmp function</a></h5>
<pre>
#include <a href="#7.28"><wchar.h></a>
int wmemcmp(const wchar_t *s1, const wchar_t *s2,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wmemcmp function compares the first n wide characters of the object pointed to by
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- wchar_t *wcschr(const wchar_t *s, wchar_t c);</pre>
+ wchar_t *wcschr(const wchar_t *s, wchar_t c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcschr function locates the first occurrence of c in the wide string pointed to by s.
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- size_t wcscspn(const wchar_t *s1, const wchar_t *s2);</pre>
+ size_t wcscspn(const wchar_t *s1, const wchar_t *s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcscspn function computes the length of the maximum initial segment of the wide
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- wchar_t *wcspbrk(const wchar_t *s1, const wchar_t *s2);</pre>
+ wchar_t *wcspbrk(const wchar_t *s1, const wchar_t *s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcspbrk function locates the first occurrence in the wide string pointed to by s1 of
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- wchar_t *wcsrchr(const wchar_t *s, wchar_t c);</pre>
+ wchar_t *wcsrchr(const wchar_t *s, wchar_t c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcsrchr function locates the last occurrence of c in the wide string pointed to by
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- size_t wcsspn(const wchar_t *s1, const wchar_t *s2);</pre>
+ size_t wcsspn(const wchar_t *s1, const wchar_t *s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcsspn function computes the length of the maximum initial segment of the wide
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- wchar_t *wcsstr(const wchar_t *s1, const wchar_t *s2);</pre>
+ wchar_t *wcsstr(const wchar_t *s1, const wchar_t *s2);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcsstr function locates the first occurrence in the wide string pointed to by s1 of
#include <a href="#7.28"><wchar.h></a>
wchar_t *wcstok(wchar_t * restrict s1,
const wchar_t * restrict s2,
- wchar_t ** restrict ptr);</pre>
+ wchar_t ** restrict ptr);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
A sequence of calls to the wcstok function breaks the wide string pointed to by s1 into
t = wcstok(NULL, L",", &ptr1); // t points to the token L"??b"
t = wcstok(str2, L" \t", &ptr2); // t is a null pointer
t = wcstok(NULL, L"#,", &ptr1); // t points to the token L"c"
- t = wcstok(NULL, L"?", &ptr1); // t is a null pointer</pre>
+ t = wcstok(NULL, L"?", &ptr1); // t is a null pointer
+</pre>
<h5><a name="7.28.4.5.8" href="#7.28.4.5.8">7.28.4.5.8 The wmemchr function</a></h5>
<pre>
#include <a href="#7.28"><wchar.h></a>
wchar_t *wmemchr(const wchar_t *s, wchar_t c,
- size_t n);</pre>
+ size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wmemchr function locates the first occurrence of c in the initial n wide characters of
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- size_t wcslen(const wchar_t *s);</pre>
+ size_t wcslen(const wchar_t *s);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcslen function computes the length of the wide string pointed to by s.
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- wchar_t *wmemset(wchar_t *s, wchar_t c, size_t n);</pre>
+ wchar_t *wmemset(wchar_t *s, wchar_t c, size_t n);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wmemset function copies the value of c into each of the first n wide characters of
size_t wcsftime(wchar_t * restrict s,
size_t maxsize,
const wchar_t * restrict format,
- const struct tm * restrict timeptr);</pre>
+ const struct tm * restrict timeptr);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcsftime function is equivalent to the strftime function, except that:
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a> *
- wint_t btowc(int c);</pre>
+ wint_t btowc(int c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The btowc function determines whether c constitutes a valid single-byte character in the
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a> *
- int wctob(wint_t c);</pre>
+ int wctob(wint_t c);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wctob function determines whether c corresponds to a member of the extended
<p><!--para 1 -->
<pre>
#include <a href="#7.28"><wchar.h></a>
- int mbsinit(const mbstate_t *ps);</pre>
+ int mbsinit(const mbstate_t *ps);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If ps is not a null pointer, the mbsinit function determines whether the referenced
#include <a href="#7.28"><wchar.h></a>
size_t mbrlen(const char * restrict s,
size_t n,
- mbstate_t * restrict ps);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The mbrlen function is equivalent to the call:
<pre>
- mbrtowc(NULL, s, n, ps != NULL ? ps : &internal)</pre>
+ mbrtowc(NULL, s, n, ps != NULL ? ps : &internal)
+</pre>
where internal is the mbstate_t object for the mbrlen function, except that the
expression designated by ps is evaluated only once.
<h6>Returns</h6>
size_t mbrtowc(wchar_t * restrict pwc,
const char * restrict s,
size_t n,
- mbstate_t * restrict ps);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If s is a null pointer, the mbrtowc function is equivalent to the call:
<pre>
- mbrtowc(NULL, "", 1, ps)</pre>
+ mbrtowc(NULL, "", 1, ps)
+</pre>
In this case, the values of the parameters pwc and n are ignored.
<p><!--para 3 -->
If s is not a null pointer, the mbrtowc function inspects at most n bytes beginning with
conversion state):
0 if the next n or fewer bytes complete the multibyte character that
<pre>
- corresponds to the null wide character (which is the value stored).</pre>
+ corresponds to the null wide character (which is the value stored).
+</pre>
between 1 and n inclusive if the next n or fewer bytes complete a valid multibyte
<pre>
character (which is the value stored); the value returned is the number
- of bytes that complete the multibyte character.</pre>
+ of bytes that complete the multibyte character.
+</pre>
(size_t)(-2) if the next n bytes contribute to an incomplete (but potentially valid)
<pre>
multibyte character, and all n bytes have been processed (no value is
- stored).<sup><a href="#note336"><b>336)</b></a></sup></pre>
+ stored).<sup><a href="#note336"><b>336)</b></a></sup>
+</pre>
(size_t)(-1) if an encoding error occurs, in which case the next n or fewer bytes
<pre>
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.</pre>
+ and the conversion state is unspecified.
+</pre>
<!--page 459 -->
#include <a href="#7.28"><wchar.h></a>
size_t wcrtomb(char * restrict s,
wchar_t wc,
- mbstate_t * restrict ps);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
If s is a null pointer, the wcrtomb function is equivalent to the call
<pre>
- wcrtomb(buf, L'\0', ps)</pre>
+ wcrtomb(buf, L'\0', ps)
+</pre>
where buf is an internal buffer.
<p><!--para 3 -->
If s is not a null pointer, the wcrtomb function determines the number of bytes needed
size_t mbsrtowcs(wchar_t * restrict dst,
const char ** restrict src,
size_t len,
- mbstate_t * restrict ps);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The mbsrtowcs function converts a sequence of multibyte characters that begins in the
size_t wcsrtombs(char * restrict dst,
const wchar_t ** restrict src,
size_t len,
- mbstate_t * restrict ps);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcsrtombs function converts a sequence of wide characters from the array
<p><!--para 2 -->
The types declared are
<pre>
- wint_t</pre>
+ wint_t
+</pre>
described in <a href="#7.28.1">7.28.1</a>;
<pre>
- wctrans_t</pre>
+ wctrans_t
+</pre>
which is a scalar type that can hold values which represent locale-specific character
mappings; and
<pre>
- wctype_t</pre>
+ wctype_t
+</pre>
which is a scalar type that can hold values which represent locale-specific character
classifications.
<p><!--para 3 -->
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswalnum(wint_t wc);</pre>
+ int iswalnum(wint_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The iswalnum function tests for any wide character for which iswalpha or
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswalpha(wint_t wc);</pre>
+ int iswalpha(wint_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The iswalpha function tests for any wide character for which iswupper or
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswblank(wint_t wc);</pre>
+ int iswblank(wint_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The iswblank function tests for any wide character that is a standard blank wide
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswcntrl(wint_t wc);</pre>
+ int iswcntrl(wint_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The iswcntrl function tests for any control wide character.
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswdigit(wint_t wc);</pre>
+ int iswdigit(wint_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The iswdigit function tests for any wide character that corresponds to a decimal-digit
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswgraph(wint_t wc);</pre>
+ int iswgraph(wint_t wc);
+</pre>
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswlower(wint_t wc);</pre>
+ int iswlower(wint_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The iswlower function tests for any wide character that corresponds to a lowercase
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswprint(wint_t wc);</pre>
+ int iswprint(wint_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The iswprint function tests for any printing wide character.
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswpunct(wint_t wc);</pre>
+ int iswpunct(wint_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The iswpunct function tests for any printing wide character that is one of a locale-
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswspace(wint_t wc);</pre>
+ int iswspace(wint_t wc);
+</pre>
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswupper(wint_t wc);</pre>
+ int iswupper(wint_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The iswupper function tests for any wide character that corresponds to an uppercase
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswxdigit(wint_t wc);</pre>
+ int iswxdigit(wint_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The iswxdigit function tests for any wide character that corresponds to a
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- int iswctype(wint_t wc, wctype_t desc);</pre>
+ int iswctype(wint_t wc, wctype_t desc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The iswctype function determines whether the wide character wc has the property
iswctype(wc, wctype("punct")) // iswpunct(wc)
iswctype(wc, wctype("space")) // iswspace(wc)
iswctype(wc, wctype("upper")) // iswupper(wc)
- iswctype(wc, wctype("xdigit")) // iswxdigit(wc)</pre>
+ iswctype(wc, wctype("xdigit")) // iswxdigit(wc)
+</pre>
<h6>Returns</h6>
<p><!--para 4 -->
The iswctype function returns nonzero (true) if and only if the value of the wide
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- wctype_t wctype(const char *property);</pre>
+ wctype_t wctype(const char *property);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wctype function constructs a value with type wctype_t that describes a class of
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- wint_t towlower(wint_t wc);</pre>
+ wint_t towlower(wint_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The towlower function converts an uppercase letter to a corresponding lowercase letter.
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- wint_t towupper(wint_t wc);</pre>
+ wint_t towupper(wint_t wc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The towupper function converts a lowercase letter to a corresponding uppercase letter.
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- wint_t towctrans(wint_t wc, wctrans_t desc);</pre>
+ wint_t towctrans(wint_t wc, wctrans_t desc);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The towctrans function maps the wide character wc using the mapping described by
mapping function (<a href="#7.29.3.1">7.29.3.1</a>) in the comment that follows the expression:
<pre>
towctrans(wc, wctrans("tolower")) // towlower(wc)
- towctrans(wc, wctrans("toupper")) // towupper(wc)</pre>
+ towctrans(wc, wctrans("toupper")) // towupper(wc)
+</pre>
<h6>Returns</h6>
<p><!--para 4 -->
The towctrans function returns the mapped value of wc using the mapping described
<p><!--para 1 -->
<pre>
#include <a href="#7.29"><wctype.h></a>
- wctrans_t wctrans(const char *property);</pre>
+ wctrans_t wctrans(const char *property);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wctrans function constructs a value with type wctrans_t that describes a
<pre>
cerf cexpm1 clog2
cerfc clog10 clgamma
- cexp2 clog1p ctgamma</pre>
+ cexp2 clog1p ctgamma
+</pre>
and the same names suffixed with f or l may be added to the declarations in the
<a href="#7.3"><complex.h></a> header.
<h2><a name="A" href="#A">Annex A</a></h2>
<pre>
(informative)
- Language syntax summary</pre>
+ Language syntax summary
+</pre>
<p><!--para 1 -->
NOTE The notation is described in <a href="#6.1">6.1</a>.
identifier
constant
string-literal
- punctuator</pre>
+ punctuator
+</pre>
(<a href="#6.4">6.4</a>) preprocessing-token:
<!--page 473 -->
<pre>
character-constant
string-literal
punctuator
- each non-white-space character that cannot be one of the above</pre>
+ each non-white-space character that cannot be one of the above
+</pre>
<h4><a name="A.1.2" href="#A.1.2">A.1.2 Keywords</a></h4>
(<a href="#6.4.1">6.4.1</a>) keyword: one of
enum static _Noreturn
extern struct _Static_assert
float switch _Thread_local
- for typedef</pre>
+ for typedef
+</pre>
<h4><a name="A.1.3" href="#A.1.3">A.1.3 Identifiers</a></h4>
(<a href="#6.4.2.1">6.4.2.1</a>) identifier:
<pre>
identifier-nondigit
identifier identifier-nondigit
- identifier digit</pre>
+ identifier digit
+</pre>
(<a href="#6.4.2.1">6.4.2.1</a>) identifier-nondigit:
<pre>
nondigit
universal-character-name
- other implementation-defined characters</pre>
+ other implementation-defined characters
+</pre>
(<a href="#6.4.2.1">6.4.2.1</a>) nondigit: one of
<pre>
_ a b c d e f g h i j k l m
n o p q r s t u v w x y z
A B C D E F G H I J K L M
- N O P Q R S T U V W X Y Z</pre>
+ N O P Q R S T U V W X Y Z
+</pre>
(<a href="#6.4.2.1">6.4.2.1</a>) digit: one of
<!--page 474 -->
<pre>
- 0 1 2 3 4 5 6 7 8 9</pre>
+ 0 1 2 3 4 5 6 7 8 9
+</pre>
<h4><a name="A.1.4" href="#A.1.4">A.1.4 Universal character names</a></h4>
(<a href="#6.4.3">6.4.3</a>) universal-character-name:
<pre>
\u hex-quad
- \U hex-quad hex-quad</pre>
+ \U hex-quad hex-quad
+</pre>
(<a href="#6.4.3">6.4.3</a>) hex-quad:
<pre>
hexadecimal-digit hexadecimal-digit
- hexadecimal-digit hexadecimal-digit</pre>
+ hexadecimal-digit hexadecimal-digit
+</pre>
<h4><a name="A.1.5" href="#A.1.5">A.1.5 Constants</a></h4>
(<a href="#6.4.4">6.4.4</a>) constant:
integer-constant
floating-constant
enumeration-constant
- character-constant</pre>
+ character-constant
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) integer-constant:
<pre>
decimal-constant integer-suffix<sub>opt</sub>
octal-constant integer-suffix<sub>opt</sub>
- hexadecimal-constant integer-suffix<sub>opt</sub></pre>
+ hexadecimal-constant integer-suffix<sub>opt</sub>
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) decimal-constant:
<pre>
nonzero-digit
- decimal-constant digit</pre>
+ decimal-constant digit
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) octal-constant:
<pre>
0
- octal-constant octal-digit</pre>
+ octal-constant octal-digit
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) hexadecimal-constant:
<pre>
hexadecimal-prefix hexadecimal-digit
- hexadecimal-constant hexadecimal-digit</pre>
+ hexadecimal-constant hexadecimal-digit
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) hexadecimal-prefix: one of
<pre>
- 0x 0X</pre>
+ 0x 0X
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) nonzero-digit: one of
<pre>
- 1 2 3 4 5 6 7 8 9</pre>
+ 1 2 3 4 5 6 7 8 9
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) octal-digit: one of
<!--page 475 -->
<pre>
- 0 1 2 3 4 5 6 7</pre>
+ 0 1 2 3 4 5 6 7
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) hexadecimal-digit: one of
<pre>
0 1 2 3 4 5 6 7 8 9
a b c d e f
- A B C D E F</pre>
+ A B C D E F
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) integer-suffix:
<pre>
unsigned-suffix long-suffix<sub>opt</sub>
unsigned-suffix long-long-suffix
long-suffix unsigned-suffix<sub>opt</sub>
- long-long-suffix unsigned-suffix<sub>opt</sub></pre>
+ long-long-suffix unsigned-suffix<sub>opt</sub>
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) unsigned-suffix: one of
<pre>
- u U</pre>
+ u U
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) long-suffix: one of
<pre>
- l L</pre>
+ l L
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) long-long-suffix: one of
<pre>
- ll LL</pre>
+ ll LL
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) floating-constant:
<pre>
decimal-floating-constant
- hexadecimal-floating-constant</pre>
+ hexadecimal-floating-constant
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) decimal-floating-constant:
<pre>
fractional-constant exponent-part<sub>opt</sub> floating-suffix<sub>opt</sub>
- digit-sequence exponent-part floating-suffix<sub>opt</sub></pre>
+ digit-sequence exponent-part floating-suffix<sub>opt</sub>
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) hexadecimal-floating-constant:
<pre>
hexadecimal-prefix hexadecimal-fractional-constant
binary-exponent-part floating-suffix<sub>opt</sub>
hexadecimal-prefix hexadecimal-digit-sequence
- binary-exponent-part floating-suffix<sub>opt</sub></pre>
+ binary-exponent-part floating-suffix<sub>opt</sub>
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) fractional-constant:
<pre>
digit-sequence<sub>opt</sub> . digit-sequence
- digit-sequence .</pre>
+ digit-sequence .
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) exponent-part:
<pre>
e sign<sub>opt</sub> digit-sequence
- E sign<sub>opt</sub> digit-sequence</pre>
+ E sign<sub>opt</sub> digit-sequence
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) sign: one of
<!--page 476 -->
<pre>
- + -</pre>
+ + -
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) digit-sequence:
<pre>
digit
- digit-sequence digit</pre>
+ digit-sequence digit
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) hexadecimal-fractional-constant:
<pre>
hexadecimal-digit-sequence<sub>opt</sub> .
hexadecimal-digit-sequence
- hexadecimal-digit-sequence .</pre>
+ hexadecimal-digit-sequence .
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) binary-exponent-part:
<pre>
p sign<sub>opt</sub> digit-sequence
- P sign<sub>opt</sub> digit-sequence</pre>
+ P sign<sub>opt</sub> digit-sequence
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) hexadecimal-digit-sequence:
<pre>
hexadecimal-digit
- hexadecimal-digit-sequence hexadecimal-digit</pre>
+ hexadecimal-digit-sequence hexadecimal-digit
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) floating-suffix: one of
<pre>
- f l F L</pre>
+ f l F L
+</pre>
(<a href="#6.4.4.3">6.4.4.3</a>) enumeration-constant:
<pre>
- identifier</pre>
+ identifier
+</pre>
(<a href="#6.4.4.4">6.4.4.4</a>) character-constant:
<pre>
' c-char-sequence '
L' c-char-sequence '
u' c-char-sequence '
- U' c-char-sequence '</pre>
+ U' c-char-sequence '
+</pre>
(<a href="#6.4.4.4">6.4.4.4</a>) c-char-sequence:
<pre>
c-char
- c-char-sequence c-char</pre>
+ c-char-sequence c-char
+</pre>
(<a href="#6.4.4.4">6.4.4.4</a>) c-char:
<pre>
any member of the source character set except
the single-quote ', backslash \, or new-line character
- escape-sequence</pre>
+ escape-sequence
+</pre>
(<a href="#6.4.4.4">6.4.4.4</a>) escape-sequence:
<!--page 477 -->
<pre>
simple-escape-sequence
octal-escape-sequence
hexadecimal-escape-sequence
- universal-character-name</pre>
+ universal-character-name
+</pre>
(<a href="#6.4.4.4">6.4.4.4</a>) simple-escape-sequence: one of
<pre>
\' \" \? \\
- \a \b \f \n \r \t \v</pre>
+ \a \b \f \n \r \t \v
+</pre>
(<a href="#6.4.4.4">6.4.4.4</a>) octal-escape-sequence:
<pre>
\ octal-digit
\ octal-digit octal-digit
- \ octal-digit octal-digit octal-digit</pre>
+ \ octal-digit octal-digit octal-digit
+</pre>
(<a href="#6.4.4.4">6.4.4.4</a>) hexadecimal-escape-sequence:
<pre>
\x hexadecimal-digit
- hexadecimal-escape-sequence hexadecimal-digit</pre>
+ hexadecimal-escape-sequence hexadecimal-digit
+</pre>
<h4><a name="A.1.6" href="#A.1.6">A.1.6 String literals</a></h4>
(<a href="#6.4.5">6.4.5</a>) string-literal:
<pre>
- encoding-prefix<sub>opt</sub> " s-char-sequence<sub>opt</sub> "</pre>
+ encoding-prefix<sub>opt</sub> " s-char-sequence<sub>opt</sub> "
+</pre>
(<a href="#6.4.5">6.4.5</a>) encoding-prefix:
<pre>
u8
u
U
- L</pre>
+ L
+</pre>
(<a href="#6.4.5">6.4.5</a>) s-char-sequence:
<pre>
s-char
- s-char-sequence s-char</pre>
+ s-char-sequence s-char
+</pre>
(<a href="#6.4.5">6.4.5</a>) s-char:
<pre>
any member of the source character set except
the double-quote ", backslash \, or new-line character
- escape-sequence</pre>
+ escape-sequence
+</pre>
<h4><a name="A.1.7" href="#A.1.7">A.1.7 Punctuators</a></h4>
(<a href="#6.4.6">6.4.6</a>) punctuator: one of
? : ; ...
= *= /= %= += -= <<= >>= &= ^= |=
, # ##
- <: :> <% %> %: %:%:</pre>
+ <: :> <% %> %: %:%:
+</pre>
<h4><a name="A.1.8" href="#A.1.8">A.1.8 Header names</a></h4>
(<a href="#6.4.7">6.4.7</a>) header-name:
<pre>
< h-char-sequence >
- " q-char-sequence "</pre>
+ " q-char-sequence "
+</pre>
(<a href="#6.4.7">6.4.7</a>) h-char-sequence:
<pre>
h-char
- h-char-sequence h-char</pre>
+ h-char-sequence h-char
+</pre>
(<a href="#6.4.7">6.4.7</a>) h-char:
<pre>
any member of the source character set except
- the new-line character and ></pre>
+ the new-line character and >
+</pre>
(<a href="#6.4.7">6.4.7</a>) q-char-sequence:
<pre>
q-char
- q-char-sequence q-char</pre>
+ q-char-sequence q-char
+</pre>
(<a href="#6.4.7">6.4.7</a>) q-char:
<pre>
any member of the source character set except
- the new-line character and "</pre>
+ the new-line character and "
+</pre>
<h4><a name="A.1.9" href="#A.1.9">A.1.9 Preprocessing numbers</a></h4>
(<a href="#6.4.8">6.4.8</a>) pp-number:
pp-number E sign
pp-number p sign
pp-number P sign
- pp-number .</pre>
+ pp-number .
+</pre>
<h3><a name="A.2" href="#A.2">A.2 Phrase structure grammar</a></h3>
constant
string-literal
( expression )
- generic-selection</pre>
+ generic-selection
+</pre>
(<a href="#6.5.1.1">6.5.1.1</a>) generic-selection:
<pre>
- _Generic ( assignment-expression , generic-assoc-list )</pre>
+ _Generic ( assignment-expression , generic-assoc-list )
+</pre>
(<a href="#6.5.1.1">6.5.1.1</a>) generic-assoc-list:
<pre>
generic-association
- generic-assoc-list , generic-association</pre>
+ generic-assoc-list , generic-association
+</pre>
(<a href="#6.5.1.1">6.5.1.1</a>) generic-association:
<pre>
type-name : assignment-expression
- default : assignment-expression</pre>
+ default : assignment-expression
+</pre>
(<a href="#6.5.2">6.5.2</a>) postfix-expression:
<pre>
primary-expression
postfix-expression ++
postfix-expression --
( type-name ) { initializer-list }
- ( type-name ) { initializer-list , }</pre>
+ ( type-name ) { initializer-list , }
+</pre>
(<a href="#6.5.2">6.5.2</a>) argument-expression-list:
<pre>
assignment-expression
- argument-expression-list , assignment-expression</pre>
+ argument-expression-list , assignment-expression
+</pre>
(<a href="#6.5.3">6.5.3</a>) unary-expression:
<!--page 480 -->
<pre>
unary-operator cast-expression
sizeof unary-expression
sizeof ( type-name )
- alignof ( type-name )</pre>
+ alignof ( type-name )
+</pre>
(<a href="#6.5.3">6.5.3</a>) unary-operator: one of
<pre>
- & * + - ~ !</pre>
+ & * + - ~ !
+</pre>
(<a href="#6.5.4">6.5.4</a>) cast-expression:
<pre>
unary-expression
- ( type-name ) cast-expression</pre>
+ ( type-name ) cast-expression
+</pre>
(<a href="#6.5.5">6.5.5</a>) multiplicative-expression:
<pre>
cast-expression
multiplicative-expression * cast-expression
multiplicative-expression / cast-expression
- multiplicative-expression % cast-expression</pre>
+ multiplicative-expression % cast-expression
+</pre>
(<a href="#6.5.6">6.5.6</a>) additive-expression:
<pre>
multiplicative-expression
additive-expression + multiplicative-expression
- additive-expression - multiplicative-expression</pre>
+ additive-expression - multiplicative-expression
+</pre>
(<a href="#6.5.7">6.5.7</a>) shift-expression:
<pre>
additive-expression
shift-expression << additive-expression
- shift-expression >> additive-expression</pre>
+ shift-expression >> additive-expression
+</pre>
(<a href="#6.5.8">6.5.8</a>) relational-expression:
<pre>
shift-expression
relational-expression < shift-expression
relational-expression > shift-expression
relational-expression <= shift-expression
- relational-expression >= shift-expression</pre>
+ relational-expression >= shift-expression
+</pre>
(<a href="#6.5.9">6.5.9</a>) equality-expression:
<pre>
relational-expression
equality-expression == relational-expression
- equality-expression != relational-expression</pre>
+ equality-expression != relational-expression
+</pre>
(<a href="#6.5.10">6.5.10</a>) AND-expression:
<pre>
equality-expression
- AND-expression & equality-expression</pre>
+ AND-expression & equality-expression
+</pre>
(<a href="#6.5.11">6.5.11</a>) exclusive-OR-expression:
<!--page 481 -->
<pre>
AND-expression
- exclusive-OR-expression ^ AND-expression</pre>
+ exclusive-OR-expression ^ AND-expression
+</pre>
(<a href="#6.5.12">6.5.12</a>) inclusive-OR-expression:
<pre>
exclusive-OR-expression
- inclusive-OR-expression | exclusive-OR-expression</pre>
+ inclusive-OR-expression | exclusive-OR-expression
+</pre>
(<a href="#6.5.13">6.5.13</a>) logical-AND-expression:
<pre>
inclusive-OR-expression
- logical-AND-expression && inclusive-OR-expression</pre>
+ logical-AND-expression && inclusive-OR-expression
+</pre>
(<a href="#6.5.14">6.5.14</a>) logical-OR-expression:
<pre>
logical-AND-expression
- logical-OR-expression || logical-AND-expression</pre>
+ logical-OR-expression || logical-AND-expression
+</pre>
(<a href="#6.5.15">6.5.15</a>) conditional-expression:
<pre>
logical-OR-expression
- logical-OR-expression ? expression : conditional-expression</pre>
+ logical-OR-expression ? expression : conditional-expression
+</pre>
(<a href="#6.5.16">6.5.16</a>) assignment-expression:
<pre>
conditional-expression
- unary-expression assignment-operator assignment-expression</pre>
+ unary-expression assignment-operator assignment-expression
+</pre>
(<a href="#6.5.16">6.5.16</a>) assignment-operator: one of
<pre>
- = *= /= %= += -= <<= >>= &= ^= |=</pre>
+ = *= /= %= += -= <<= >>= &= ^= |=
+</pre>
(<a href="#6.5.17">6.5.17</a>) expression:
<pre>
assignment-expression
- expression , assignment-expression</pre>
+ expression , assignment-expression
+</pre>
(<a href="#6.6">6.6</a>) constant-expression:
<pre>
- conditional-expression</pre>
+ conditional-expression
+</pre>
<h4><a name="A.2.2" href="#A.2.2">A.2.2 Declarations</a></h4>
(<a href="#6.7">6.7</a>) declaration:
<pre>
declaration-specifiers init-declarator-list<sub>opt</sub> ;
- static_assert-declaration</pre>
+ static_assert-declaration
+</pre>
(<a href="#6.7">6.7</a>) declaration-specifiers:
<pre>
storage-class-specifier declaration-specifiers<sub>opt</sub>
type-specifier declaration-specifiers<sub>opt</sub>
type-qualifier declaration-specifiers<sub>opt</sub>
function-specifier declaration-specifiers<sub>opt</sub>
- alignment-specifier declaration-specifiers<sub>opt</sub></pre>
+ alignment-specifier declaration-specifiers<sub>opt</sub>
+</pre>
(<a href="#6.7">6.7</a>) init-declarator-list:
<!--page 482 -->
<pre>
init-declarator
- init-declarator-list , init-declarator</pre>
+ init-declarator-list , init-declarator
+</pre>
(<a href="#6.7">6.7</a>) init-declarator:
<pre>
declarator
- declarator = initializer</pre>
+ declarator = initializer
+</pre>
(<a href="#6.7.1">6.7.1</a>) storage-class-specifier:
<pre>
typedef
static
_Thread_local
auto
- register</pre>
+ register
+</pre>
(<a href="#6.7.2">6.7.2</a>) type-specifier:
<pre>
void
atomic-type-specifier
struct-or-union-specifier
enum-specifier
- typedef-name</pre>
+ typedef-name
+</pre>
(<a href="#6.7.2.1">6.7.2.1</a>) struct-or-union-specifier:
<pre>
struct-or-union identifier<sub>opt</sub> { struct-declaration-list }
- struct-or-union identifier</pre>
+ struct-or-union identifier
+</pre>
(<a href="#6.7.2.1">6.7.2.1</a>) struct-or-union:
<pre>
struct
- union</pre>
+ union
+</pre>
(<a href="#6.7.2.1">6.7.2.1</a>) struct-declaration-list:
<pre>
struct-declaration
- struct-declaration-list struct-declaration</pre>
+ struct-declaration-list struct-declaration
+</pre>
(<a href="#6.7.2.1">6.7.2.1</a>) struct-declaration:
<!--page 483 -->
<pre>
specifier-qualifier-list struct-declarator-list<sub>opt</sub> ;
- static_assert-declaration</pre>
+ static_assert-declaration
+</pre>
(<a href="#6.7.2.1">6.7.2.1</a>) specifier-qualifier-list:
<pre>
type-specifier specifier-qualifier-list<sub>opt</sub>
- type-qualifier specifier-qualifier-list<sub>opt</sub></pre>
+ type-qualifier specifier-qualifier-list<sub>opt</sub>
+</pre>
(<a href="#6.7.2.1">6.7.2.1</a>) struct-declarator-list:
<pre>
struct-declarator
- struct-declarator-list , struct-declarator</pre>
+ struct-declarator-list , struct-declarator
+</pre>
(<a href="#6.7.2.1">6.7.2.1</a>) struct-declarator:
<pre>
declarator
- declarator<sub>opt</sub> : constant-expression</pre>
+ declarator<sub>opt</sub> : constant-expression
+</pre>
(<a href="#6.7.2.2">6.7.2.2</a>) enum-specifier:
<pre>
enum identifier<sub>opt</sub> { enumerator-list }
enum identifier<sub>opt</sub> { enumerator-list , }
- enum identifier</pre>
+ enum identifier
+</pre>
(<a href="#6.7.2.2">6.7.2.2</a>) enumerator-list:
<pre>
enumerator
- enumerator-list , enumerator</pre>
+ enumerator-list , enumerator
+</pre>
(<a href="#6.7.2.2">6.7.2.2</a>) enumerator:
<pre>
enumeration-constant
- enumeration-constant = constant-expression</pre>
+ enumeration-constant = constant-expression
+</pre>
(<a href="#6.7.2.4">6.7.2.4</a>) atomic-type-specifier:
<pre>
- _Atomic ( type-name )</pre>
+ _Atomic ( type-name )
+</pre>
(<a href="#6.7.3">6.7.3</a>) type-qualifier:
<pre>
const
restrict
volatile
- _Atomic</pre>
+ _Atomic
+</pre>
(<a href="#6.7.4">6.7.4</a>) function-specifier:
<pre>
inline
- _Noreturn</pre>
+ _Noreturn
+</pre>
(<a href="#6.7.5">6.7.5</a>) alignment-specifier:
<pre>
_Alignas ( type-name )
- _Alignas ( constant-expression )</pre>
+ _Alignas ( constant-expression )
+</pre>
(<a href="#6.7.6">6.7.6</a>) declarator:
<!--page 484 -->
<pre>
- pointer<sub>opt</sub> direct-declarator</pre>
+ pointer<sub>opt</sub> direct-declarator
+</pre>
(<a href="#6.7.6">6.7.6</a>) direct-declarator:
<pre>
identifier
direct-declarator [ type-qualifier-list static assignment-expression ]
direct-declarator [ type-qualifier-list<sub>opt</sub> * ]
direct-declarator ( parameter-type-list )
- direct-declarator ( identifier-list<sub>opt</sub> )</pre>
+ direct-declarator ( identifier-list<sub>opt</sub> )
+</pre>
(<a href="#6.7.6">6.7.6</a>) pointer:
<pre>
* type-qualifier-list<sub>opt</sub>
- * type-qualifier-list<sub>opt</sub> pointer</pre>
+ * type-qualifier-list<sub>opt</sub> pointer
+</pre>
(<a href="#6.7.6">6.7.6</a>) type-qualifier-list:
<pre>
type-qualifier
- type-qualifier-list type-qualifier</pre>
+ type-qualifier-list type-qualifier
+</pre>
(<a href="#6.7.6">6.7.6</a>) parameter-type-list:
<pre>
parameter-list
- parameter-list , ...</pre>
+ parameter-list , ...
+</pre>
(<a href="#6.7.6">6.7.6</a>) parameter-list:
<pre>
parameter-declaration
- parameter-list , parameter-declaration</pre>
+ parameter-list , parameter-declaration
+</pre>
(<a href="#6.7.6">6.7.6</a>) parameter-declaration:
<pre>
declaration-specifiers declarator
- declaration-specifiers abstract-declarator<sub>opt</sub></pre>
+ declaration-specifiers abstract-declarator<sub>opt</sub>
+</pre>
(<a href="#6.7.6">6.7.6</a>) identifier-list:
<pre>
identifier
- identifier-list , identifier</pre>
+ identifier-list , identifier
+</pre>
(<a href="#6.7.7">6.7.7</a>) type-name:
<pre>
- specifier-qualifier-list abstract-declarator<sub>opt</sub></pre>
+ specifier-qualifier-list abstract-declarator<sub>opt</sub>
+</pre>
(<a href="#6.7.7">6.7.7</a>) abstract-declarator:
<!--page 485 -->
<pre>
pointer
- pointer<sub>opt</sub> direct-abstract-declarator</pre>
+ pointer<sub>opt</sub> direct-abstract-declarator
+</pre>
(<a href="#6.7.7">6.7.7</a>) direct-abstract-declarator:
<pre>
( abstract-declarator )
direct-abstract-declarator<sub>opt</sub> [ type-qualifier-list static
assignment-expression ]
direct-abstract-declarator<sub>opt</sub> [ * ]
- direct-abstract-declarator<sub>opt</sub> ( parameter-type-list<sub>opt</sub> )</pre>
+ direct-abstract-declarator<sub>opt</sub> ( parameter-type-list<sub>opt</sub> )
+</pre>
(<a href="#6.7.8">6.7.8</a>) typedef-name:
<pre>
- identifier</pre>
+ identifier
+</pre>
(<a href="#6.7.9">6.7.9</a>) initializer:
<pre>
assignment-expression
{ initializer-list }
- { initializer-list , }</pre>
+ { initializer-list , }
+</pre>
(<a href="#6.7.9">6.7.9</a>) initializer-list:
<pre>
designation<sub>opt</sub> initializer
- initializer-list , designation<sub>opt</sub> initializer</pre>
+ initializer-list , designation<sub>opt</sub> initializer
+</pre>
(<a href="#6.7.9">6.7.9</a>) designation:
<pre>
- designator-list =</pre>
+ designator-list =
+</pre>
(<a href="#6.7.9">6.7.9</a>) designator-list:
<pre>
designator
- designator-list designator</pre>
+ designator-list designator
+</pre>
(<a href="#6.7.9">6.7.9</a>) designator:
<pre>
[ constant-expression ]
- . identifier</pre>
+ . identifier
+</pre>
(<a href="#6.7.10">6.7.10</a>) static_assert-declaration:
<!--page 486 -->
<pre>
- _Static_assert ( constant-expression , string-literal ) ;</pre>
+ _Static_assert ( constant-expression , string-literal ) ;
+</pre>
<h4><a name="A.2.3" href="#A.2.3">A.2.3 Statements</a></h4>
(<a href="#6.8">6.8</a>) statement:
expression-statement
selection-statement
iteration-statement
- jump-statement</pre>
+ jump-statement
+</pre>
(<a href="#6.8.1">6.8.1</a>) labeled-statement:
<pre>
identifier : statement
case constant-expression : statement
- default : statement</pre>
+ default : statement
+</pre>
(<a href="#6.8.2">6.8.2</a>) compound-statement:
<pre>
- { block-item-list<sub>opt</sub> }</pre>
+ { block-item-list<sub>opt</sub> }
+</pre>
(<a href="#6.8.2">6.8.2</a>) block-item-list:
<pre>
block-item
- block-item-list block-item</pre>
+ block-item-list block-item
+</pre>
(<a href="#6.8.2">6.8.2</a>) block-item:
<pre>
declaration
- statement</pre>
+ statement
+</pre>
(<a href="#6.8.3">6.8.3</a>) expression-statement:
<pre>
- expression<sub>opt</sub> ;</pre>
+ expression<sub>opt</sub> ;
+</pre>
(<a href="#6.8.4">6.8.4</a>) selection-statement:
<pre>
if ( expression ) statement
if ( expression ) statement else statement
- switch ( expression ) statement</pre>
+ switch ( expression ) statement
+</pre>
(<a href="#6.8.5">6.8.5</a>) iteration-statement:
<pre>
while ( expression ) statement
do statement while ( expression ) ;
for ( expression<sub>opt</sub> ; expression<sub>opt</sub> ; expression<sub>opt</sub> ) statement
- for ( declaration expression<sub>opt</sub> ; expression<sub>opt</sub> ) statement</pre>
+ for ( declaration expression<sub>opt</sub> ; expression<sub>opt</sub> ) statement
+</pre>
(<a href="#6.8.6">6.8.6</a>) jump-statement:
<!--page 487 -->
<pre>
goto identifier ;
continue ;
break ;
- return expression<sub>opt</sub> ;</pre>
+ return expression<sub>opt</sub> ;
+</pre>
<h4><a name="A.2.4" href="#A.2.4">A.2.4 External definitions</a></h4>
(<a href="#6.9">6.9</a>) translation-unit:
<pre>
external-declaration
- translation-unit external-declaration</pre>
+ translation-unit external-declaration
+</pre>
(<a href="#6.9">6.9</a>) external-declaration:
<pre>
function-definition
- declaration</pre>
+ declaration
+</pre>
(<a href="#6.9.1">6.9.1</a>) function-definition:
<pre>
- declaration-specifiers declarator declaration-list<sub>opt</sub> compound-statement</pre>
+ declaration-specifiers declarator declaration-list<sub>opt</sub> compound-statement
+</pre>
(<a href="#6.9.1">6.9.1</a>) declaration-list:
<pre>
declaration
- declaration-list declaration</pre>
+ declaration-list declaration
+</pre>
<h3><a name="A.3" href="#A.3">A.3 Preprocessing directives</a></h3>
(<a href="#6.10">6.10</a>) preprocessing-file:
<pre>
- group<sub>opt</sub></pre>
+ group<sub>opt</sub>
+</pre>
(<a href="#6.10">6.10</a>) group:
<pre>
group-part
- group group-part</pre>
+ group group-part
+</pre>
(<a href="#6.10">6.10</a>) group-part:
<pre>
if-section
control-line
text-line
- # non-directive</pre>
+ # non-directive
+</pre>
(<a href="#6.10">6.10</a>) if-section:
<pre>
- if-group elif-groups<sub>opt</sub> else-group<sub>opt</sub> endif-line</pre>
+ if-group elif-groups<sub>opt</sub> else-group<sub>opt</sub> endif-line
+</pre>
(<a href="#6.10">6.10</a>) if-group:
<pre>
# if constant-expression new-line group<sub>opt</sub>
# ifdef identifier new-line group<sub>opt</sub>
- # ifndef identifier new-line group<sub>opt</sub></pre>
+ # ifndef identifier new-line group<sub>opt</sub>
+</pre>
(<a href="#6.10">6.10</a>) elif-groups:
<pre>
elif-group
- elif-groups elif-group</pre>
+ elif-groups elif-group
+</pre>
(<a href="#6.10">6.10</a>) elif-group:
<!--page 488 -->
<pre>
- # elif constant-expression new-line group<sub>opt</sub></pre>
+ # elif constant-expression new-line group<sub>opt</sub>
+</pre>
(<a href="#6.10">6.10</a>) else-group:
<pre>
- # else new-line group<sub>opt</sub></pre>
+ # else new-line group<sub>opt</sub>
+</pre>
(<a href="#6.10">6.10</a>) endif-line:
<pre>
- # endif new-line</pre>
+ # endif new-line
+</pre>
(<a href="#6.10">6.10</a>) control-line:
<pre>
# include pp-tokens new-line
# line pp-tokens new-line
# error pp-tokens<sub>opt</sub> new-line
# pragma pp-tokens<sub>opt</sub> new-line
- # new-line</pre>
+ # new-line
+</pre>
(<a href="#6.10">6.10</a>) text-line:
<pre>
- pp-tokens<sub>opt</sub> new-line</pre>
+ pp-tokens<sub>opt</sub> new-line
+</pre>
(<a href="#6.10">6.10</a>) non-directive:
<pre>
- pp-tokens new-line</pre>
+ pp-tokens new-line
+</pre>
(<a href="#6.10">6.10</a>) lparen:
<pre>
- a ( character not immediately preceded by white-space</pre>
+ a ( character not immediately preceded by white-space
+</pre>
(<a href="#6.10">6.10</a>) replacement-list:
<pre>
- pp-tokens<sub>opt</sub></pre>
+ pp-tokens<sub>opt</sub>
+</pre>
(<a href="#6.10">6.10</a>) pp-tokens:
<pre>
preprocessing-token
- pp-tokens preprocessing-token</pre>
+ pp-tokens preprocessing-token
+</pre>
(<a href="#6.10">6.10</a>) new-line:
<!--page 489 -->
<pre>
- the new-line character</pre>
+ the new-line character
+</pre>
<h2><a name="B" href="#B">Annex B</a></h2>
<pre>
(informative)
- Library summary</pre>
+ Library summary
+</pre>
<h3><a name="B.1" href="#B.1">B.1 Diagnostics <assert.h></a></h3>
<pre>
NDEBUG
static_assert
- void assert(scalar expression);</pre>
+ void assert(scalar expression);
+</pre>
<h3><a name="B.2" href="#B.2">B.2 Complex <complex.h></a></h3>
<!--page 490 -->
long double complex cprojl(long double complex z);
double creal(double complex z);
float crealf(float complex z);
- long double creall(long double complex z);</pre>
+ long double creall(long double complex z);
+</pre>
<h3><a name="B.3" href="#B.3">B.3 Character handling <ctype.h></a></h3>
<pre>
int isupper(int c);
int isxdigit(int c);
int tolower(int c);
- int toupper(int c);</pre>
+ int toupper(int c);
+</pre>
<h3><a name="B.4" href="#B.4">B.4 Errors <errno.h></a></h3>
<pre>
EDOM EILSEQ ERANGE errno
__STDC_WANT_LIB_EXT1__
- errno_t</pre>
+ errno_t
+</pre>
<h3><a name="B.5" href="#B.5">B.5 Floating-point environment <fenv.h></a></h3>
<!--page 492 -->
int fegetenv(fenv_t *envp);
int feholdexcept(fenv_t *envp);
int fesetenv(const fenv_t *envp);
- int feupdateenv(const fenv_t *envp);</pre>
+ int feupdateenv(const fenv_t *envp);
+</pre>
<h3><a name="B.6" href="#B.6">B.6 Characteristics of floating types <float.h></a></h3>
<pre>
DBL_DECIMAL_DIG LDBL_MAX_EXP DBL_TRUE_MIN
LDBL_DECIMAL_DIG FLT_MAX_10_EXP LDBL_TRUE_MIN
DECIMAL_DIG DBL_MAX_10_EXP
- FLT_DIG LDBL_MAX_10_EXP</pre>
+ FLT_DIG LDBL_MAX_10_EXP
+</pre>
<h3><a name="B.7" href="#B.7">B.7 Format conversion of integer types <inttypes.h></a></h3>
<!--page 493 -->
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);</pre>
+ wchar_t ** restrict endptr, int base);
+</pre>
<h3><a name="B.8" href="#B.8">B.8 Alternative spellings <iso646.h></a></h3>
<pre>
and bitor not_eq xor
and_eq compl or xor_eq
- bitand not or_eq</pre>
+ bitand not or_eq
+</pre>
<h3><a name="B.9" href="#B.9">B.9 Sizes of integer types <limits.h></a></h3>
<pre>
SCHAR_MIN MB_LEN_MAX INT_MAX LLONG_MIN
SCHAR_MAX SHRT_MIN UINT_MAX LLONG_MAX
UCHAR_MAX SHRT_MAX LONG_MIN ULLONG_MAX
- CHAR_MIN USHRT_MAX LONG_MAX</pre>
+ CHAR_MIN USHRT_MAX LONG_MAX
+</pre>
<h3><a name="B.10" href="#B.10">B.10 Localization <locale.h></a></h3>
<pre>
struct lconv LC_ALL LC_CTYPE LC_NUMERIC
NULL LC_COLLATE LC_MONETARY LC_TIME
char *setlocale(int category, const char *locale);
- struct lconv *localeconv(void);</pre>
+ struct lconv *localeconv(void);
+</pre>
<h3><a name="B.11" href="#B.11">B.11 Mathematics <math.h></a></h3>
<!--page 494 -->
int isless(real-floating x, real-floating y);
int islessequal(real-floating x, real-floating y);
int islessgreater(real-floating x, real-floating y);
- int isunordered(real-floating x, real-floating y);</pre>
+ int isunordered(real-floating x, real-floating y);
+</pre>
<h3><a name="B.12" href="#B.12">B.12 Nonlocal jumps <setjmp.h></a></h3>
<pre>
jmp_buf
int setjmp(jmp_buf env);
- _Noreturn void longjmp(jmp_buf env, int val);</pre>
+ _Noreturn void longjmp(jmp_buf env, int val);
+</pre>
<h3><a name="B.13" href="#B.13">B.13 Signal handling <signal.h></a></h3>
<!--page 499 -->
SIG_DFL SIGABRT SIGINT
SIG_ERR SIGFPE SIGSEGV
void (*signal(int sig, void (*func)(int)))(int);
- int raise(int sig);</pre>
+ int raise(int sig);
+</pre>
<h3><a name="B.14" href="#B.14">B.14 Alignment <stdalign.h></a></h3>
<pre>
alignas
- __alignas_is_defined</pre>
+ __alignas_is_defined
+</pre>
<h3><a name="B.15" href="#B.15">B.15 Variable arguments <stdarg.h></a></h3>
<pre>
type va_arg(va_list ap, type);
void va_copy(va_list dest, va_list src);
void va_end(va_list ap);
- void va_start(va_list ap, parmN);</pre>
+ void va_start(va_list ap, parmN);
+</pre>
<h3><a name="B.16" href="#B.16">B.16 Atomics <stdatomic.h></a></h3>
<!--page 500 -->
volatile atomic_flag *object, memory_order order);
void atomic_flag_clear(volatile atomic_flag *object);
void atomic_flag_clear_explicit(
- volatile atomic_flag *object, memory_order order);</pre>
+ volatile atomic_flag *object, memory_order order);
+</pre>
<h3><a name="B.17" href="#B.17">B.17 Boolean type and values <stdbool.h></a></h3>
<pre>
bool
true
false
- __bool_true_false_are_defined</pre>
+ __bool_true_false_are_defined
+</pre>
<h3><a name="B.18" href="#B.18">B.18 Common definitions <stddef.h></a></h3>
<pre>
size_t wchar_t
offsetof(type, member-designator)
__STDC_WANT_LIB_EXT1__
- rsize_t</pre>
+ rsize_t
+</pre>
<h3><a name="B.19" href="#B.19">B.19 Integer types <stdint.h></a></h3>
<!--page 502 -->
INTN_MAX UINTMAX_MAX UINTMAX_C(value)
UINTN_MAX PTRDIFF_MIN
__STDC_WANT_LIB_EXT1__
- RSIZE_MAX</pre>
+ RSIZE_MAX
+</pre>
<h3><a name="B.20" href="#B.20">B.20 Input/output <stdio.h></a></h3>
<!--page 503 -->
int vsscanf_s(const char * restrict s,
const char * restrict format,
va_list arg);
- char *gets_s(char *s, rsize_t n);</pre>
+ char *gets_s(char *s, rsize_t n);
+</pre>
<h3><a name="B.21" href="#B.21">B.21 General utilities <stdlib.h></a></h3>
<!--page 506 -->
const char * restrict src, rsize_t len);
errno_t wcstombs_s(size_t * restrict retval,
char * restrict dst, rsize_t dstmax,
- const wchar_t * restrict src, rsize_t len);</pre>
+ const wchar_t * restrict src, rsize_t len);
+</pre>
<h3><a name="B.22" href="#B.22">B.22 String handling <string.h></a></h3>
<!--page 508 -->
errno_t strerror_s(char *s, rsize_t maxsize,
errno_t errnum);
size_t strerrorlen_s(errno_t errnum);
- size_t strnlen_s(const char *s, size_t maxsize);</pre>
+ size_t strnlen_s(const char *s, size_t maxsize);
+</pre>
<h3><a name="B.23" href="#B.23">B.23 Type-generic math <tgmath.h></a></h3>
<pre>
tanh floor logb cimag
exp fma lrint conj
log fmax lround cproj
- pow fmin nearbyint creal</pre>
+ pow fmin nearbyint creal
+</pre>
<h3><a name="B.24" href="#B.24">B.24 Threads <threads.h></a></h3>
<!--page 510 -->
void tss_delete(tss_t key);
void *tss_get(tss_t key);
int tss_set(tss_t key, void *val);
- int xtime_get(xtime *xt, int base);</pre>
+ int xtime_get(xtime *xt, int base);
+</pre>
<h3><a name="B.25" href="#B.25">B.25 Date and time <time.h></a></h3>
<!--page 511 -->
struct tm *gmtime_s(const time_t * restrict timer,
struct tm * restrict result);
struct tm *localtime_s(const time_t * restrict timer,
- struct tm * restrict result);</pre>
+ struct tm * restrict result);
+</pre>
<h3><a name="B.26" href="#B.26">B.26 Unicode utilities <uchar.h></a></h3>
<pre>
const char * restrict s, size_t n,
mbstate_t * restrict ps);
size_t c32rtomb(char * restrict s, char32_t c32,
- mbstate_t * restrict ps);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h3><a name="B.27" href="#B.27">B.27 Extended multibyte/wide character utilities <wchar.h></a></h3>
<!--page 512 -->
errno_t wcsrtombs_s(size_t * restrict retval,
char * restrict dst, rsize_t dstmax,
const wchar_t ** restrict src, rsize_t len,
- mbstate_t * restrict ps);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h3><a name="B.28" href="#B.28">B.28 Wide character classification and mapping utilities <wctype.h></a></h3>
<!--page 517 -->
wint_t towlower(wint_t wc);
wint_t towupper(wint_t wc);
wint_t towctrans(wint_t wc, wctrans_t desc);
- wctrans_t wctrans(const char *property);</pre>
+ wctrans_t wctrans(const char *property);
+</pre>
<h2><a name="C" href="#C">Annex C</a></h2>
<pre>
(informative)
- Sequence points</pre>
+ Sequence points
+</pre>
<p><!--para 1 -->
The following are the sequence points described in <a href="#5.1.2.3">5.1.2.3</a>:
<ul>
<h2><a name="D" href="#D">Annex D</a></h2>
<pre>
(normative)
- Universal character names for identifiers</pre>
+ Universal character names for identifiers
+</pre>
<p><!--para 1 -->
This clause lists the hexadecimal code values that are valid in universal character names
in identifiers.
<h2><a name="E" href="#E">Annex E</a></h2>
<pre>
(informative)
- Implementation limits</pre>
+ Implementation limits
+</pre>
<p><!--para 1 -->
The contents of the header <a href="#7.10"><limits.h></a> are given below, in alphabetical order. The
minimum magnitudes shown shall be replaced by implementation-defined magnitudes
#define USHRT_MAX 65535
#define UINT_MAX 65535
#define ULONG_MAX 4294967295
- #define ULLONG_MAX 18446744073709551615</pre>
+ #define ULLONG_MAX 18446744073709551615
+</pre>
<p><!--para 2 -->
The contents of the header <a href="#7.7"><float.h></a> are given below. All integer values, except
FLT_ROUNDS, shall be constant expressions suitable for use in #if preprocessing
expressions:
<pre>
#define FLT_EVAL_METHOD
- #define FLT_ROUNDS</pre>
+ #define FLT_ROUNDS
+</pre>
<p><!--para 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
#define LDBL_MAX_10_EXP +37
#define LDBL_MAX_EXP
#define LDBL_MIN_10_EXP -37
- #define LDBL_MIN_EXP</pre>
+ #define LDBL_MIN_EXP
+</pre>
<p><!--para 5 -->
The values given in the following list shall be replaced by implementation-defined
constant expressions with values that are greater than or equal to those shown:
<pre>
#define DBL_MAX 1E+37
#define FLT_MAX 1E+37
- #define LDBL_MAX 1E+37</pre>
+ #define LDBL_MAX 1E+37
+</pre>
<p><!--para 6 -->
The values given in the following list shall be replaced by implementation-defined
constant expressions with (positive) values that are less than or equal to those shown:
#define FLT_EPSILON 1E-5
#define FLT_MIN 1E-37
#define LDBL_EPSILON 1E-9
- #define LDBL_MIN 1E-37</pre>
+ #define LDBL_MIN 1E-37
+</pre>
<h2><a name="F" href="#F">Annex F</a></h2>
<pre>
(normative)
- IEC 60559 floating-point arithmetic</pre>
+ IEC 60559 floating-point arithmetic
+</pre>
<h3><a name="F.1" href="#F.1">F.1 Introduction</a></h3>
<p><!--para 1 -->
float y = 0.0/0.0; // raises an exception
double z = 0.0/0.0; // raises an exception
/* ... */
- }</pre>
+ }
+</pre>
<p><!--para 3 -->
For the static initialization, the division is done at translation time, raising no (execution-time) floating-
point exceptions. On the other hand, for the three automatic initializations the invalid division occurs at
efficiency of translation-time evaluation through static initialization, such as
<pre>
- const static double one_third = 1.0/3.0;</pre>
+ const static double one_third = 1.0/3.0;
+</pre>
</small>
<h4><a name="F.8.5" href="#F.8.5">F.8.5 Initialization</a></h4>
float y = 1.1e75f; // may raise exceptions
long double z = 1.1e75; // does not raise exceptions
/* ... */
- }</pre>
+ }
+</pre>
<p><!--para 3 -->
The static initialization of v raises no (execution-time) floating-point exceptions because its computation is
done at translation time. The automatic initialization of u and w require an execution-time conversion to
For example, the automatic initialization
<pre>
- double_t x = 1.1e75;</pre>
+ double_t x = 1.1e75;
+</pre>
could be done at translation time, regardless of the expression evaluation method.
</small>
/* ... */
for (i = 0; i < n; i++) x + 1;
/* ... */
- }</pre>
+ }
+</pre>
x + 1 might raise floating-point exceptions, so cannot be removed. And since the loop
body might not execute (maybe 0 >= n), x + 1 cannot be moved out of the loop. (Of
course these optimizations are valid if the implementation can rule out the nettlesome
<!--page 529 -->
the preceding loop could be treated as
<pre>
- if (0 < n) x + 1;</pre>
+ if (0 < n) x + 1;
+</pre>
<h4><a name="F.9.2" href="#F.9.2">F.9.2 Expression transformations</a></h4>
<p><!--para 1 -->
<pre>
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.</pre>
+ IEC 60559 machines and others that round perfectly.
+</pre>
1 x x and x/1 -> x The expressions 1 x x, x/1, and x are equivalent (on IEC 60559
<pre>
- machines, among others).<sup><a href="#note355"><b>355)</b></a></sup></pre>
+ machines, among others).<sup><a href="#note355"><b>355)</b></a></sup>
+</pre>
x/x -> 1.0 The expressions x/x and 1.0 are not equivalent if x can be zero,
<pre>
- infinite, or NaN.</pre>
+ infinite, or NaN.
+</pre>
x - y <-> x + (-y) The expressions x - y, x + (-y), and (-y) + x are equivalent (on
<pre>
- IEC 60559 machines, among others).</pre>
+ IEC 60559 machines, among others).
+</pre>
x - y <-> -(y - x) The expressions x - y and -(y - x) are not equivalent because 1 - 1
<pre>
- is +0 but -(1 - 1) is -0 (in the default rounding direction).<sup><a href="#note356"><b>356)</b></a></sup></pre>
+ is +0 but -(1 - 1) is -0 (in the default rounding direction).<sup><a href="#note356"><b>356)</b></a></sup>
+</pre>
x - x -> 0.0 The expressions x - x and 0.0 are not equivalent if x is a NaN or
<pre>
- infinite.</pre>
+ infinite.
+</pre>
0 x x -> 0.0 The expressions 0 x x and 0.0 are not equivalent if x is a NaN,
<pre>
- infinite, or -0.</pre>
+ infinite, or -0.
+</pre>
x+0-> x The expressions x + 0 and x are not equivalent if x is -0, because
<pre>
- (-0) + (+0) yields +0 (in the default rounding direction), not -0.</pre>
+ (-0) + (+0) yields +0 (in the default rounding direction), not -0.
+</pre>
x-0-> x (+0) - (+0) yields -0 when rounding is downward (toward -(inf)), but
<pre>
+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.</pre>
+ the implementation can replace x - 0 by x, even if x might be zero.
+</pre>
-x <-> 0 - x The expressions -x and 0 - x are not equivalent if x is +0, because
<pre>
-(+0) yields -0, but 0 - (+0) yields +0 (unless rounding is
- downward).</pre>
+ downward).
+</pre>
<!--page 530 -->
Examples include:
<pre>
- 1/(1/ (+-) (inf)) is (+-) (inf)</pre>
+ 1/(1/ (+-) (inf)) is (+-) (inf)
+</pre>
and
<pre>
- conj(csqrt(z)) is csqrt(conj(z)),</pre>
+ conj(csqrt(z)) is csqrt(conj(z)),
+</pre>
for complex z.
</small>
transformation, which would be desirable if extra code were required
to cause the ''invalid'' floating-point exception for unordered cases,
could be performed provided the state of the FENV_ACCESS pragma
- is ''off''.</pre>
+ is ''off''.
+</pre>
The sense of relational operators shall be maintained. This includes handling unordered
cases as expressed by the source code.
<p><!--para 2 -->
if (a < b)
f();
else
- g();</pre>
+ g();
+</pre>
is not equivalent to
<pre>
// calls f and raises ''invalid'' if a and b are unordered
if (a >= b)
g();
else
- f();</pre>
+ f();
+</pre>
nor to
<pre>
// calls f without raising ''invalid'' if a and b are unordered
if (isgreaterequal(a,b))
g();
else
- f();</pre>
+ f();
+</pre>
nor, unless the state of the FENV_ACCESS pragma is ''off'', to
<pre>
// calls g without raising ''invalid'' if a and b are unordered
if (isless(a,b))
f();
else
- g();</pre>
+ g();
+</pre>
but is equivalent to
<!--page 531 -->
<pre>
if (!(a < b))
g();
else
- f();</pre>
+ f();
+</pre>
<h4><a name="F.9.4" href="#F.9.4">F.9.4 Constant arithmetic</a></h4>
{
*exp = (value == 0) ? 0 : (int)(1 + logb(value));
return scalbn(value, -(*exp));
- }</pre>
+ }
+</pre>
<h5><a name="F.10.3.5" href="#F.10.3.5">F.10.3.5 The ilogb functions</a></h5>
<p><!--para 1 -->
return copysign(
isinf(value) ? 0.0 :
value - (*iptr), value);
- }</pre>
+ }
+</pre>
<h5><a name="F.10.3.13" href="#F.10.3.13">F.10.3.13 The scalbn and scalbln functions</a></h5>
<p><!--para 1 -->
result = rint(x); // or nearbyint instead of rint
fesetround(save_round);
return result;
- }</pre>
+ }
+</pre>
<p><!--para 4 -->
The ceil functions may, but are not required to, raise the ''inexact'' floating-point
exception for finite non-integer arguments, as this implementation does.
}
feupdateenv(&save_env);
return result;
- }</pre>
+ }
+</pre>
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.
<!--page 542 -->
result = remainder(fabs(x), (y = fabs(y)));
if (signbit(result)) result += y;
return copysign(result, x);
- }</pre>
+ }
+</pre>
<h5><a name="F.10.7.2" href="#F.10.7.2">F.10.7.2 The remainder functions</a></h5>
<p><!--para 1 -->
The body of the fmax function might be<sup><a href="#note361"><b>361)</b></a></sup>
<pre>
{ return (isgreaterequal(x, y) ||
- isnan(y)) ? x : y; }</pre>
+ isnan(y)) ? x : y; }
+</pre>
<h6>footnotes</h6>
<p><small><a name="note361" href="#note361">361)</a> Ideally, fmax would be sensitive to the sign of zero, for example fmax(-0.0, +0.0) would
<h2><a name="G" href="#G">Annex G</a></h2>
<pre>
(normative)
- IEC 60559-compatible complex arithmetic</pre>
+ IEC 60559-compatible complex arithmetic
+</pre>
<h3><a name="G.1" href="#G.1">G.1 Introduction</a></h3>
<p><!--para 1 -->
If the operands are not both complex, then the result and floating-point exception
behavior of the * operator is defined by the usual mathematical formula:
<pre>
- * u iv u + iv</pre>
+ * u iv u + iv
+</pre>
<pre>
- x xu i(xv) (xu) + i(xv)</pre>
+ x xu i(xv) (xu) + i(xv)
+</pre>
<pre>
- iy i(yu) -yv (-yv) + i(yu)</pre>
+ iy i(yu) -yv (-yv) + i(yu)
+</pre>
<pre>
- x + iy (xu) + i(yu) (-yv) + i(xv)</pre>
+ x + iy (xu) + i(yu) (-yv) + i(xv)
+</pre>
<p><!--para 3 -->
If the second operand is not complex, then the result and floating-point exception
behavior of the / operator is defined by the usual mathematical formula:
<pre>
- / u iv</pre>
+ / u iv
+</pre>
<pre>
- x x/u i(-x/v)</pre>
+ x x/u i(-x/v)
+</pre>
<pre>
- iy i(y/u) y/v</pre>
+ iy i(y/u) y/v
+</pre>
<pre>
- x + iy (x/u) + i(y/u) (y/v) + i(-x/v)</pre>
+ x + iy (x/u) + i(y/u) (y/v) + i(-x/v)
+</pre>
<p><!--para 4 -->
The * and / operators satisfy the following infinity properties for all real, imaginary, and
complex operands:<sup><a href="#note364"><b>364)</b></a></sup>
}
}
return x + I * y;
- }</pre>
+ }
+</pre>
<p><!--para 7 -->
This implementation achieves the required treatment of infinities at the cost of only one isnan test in
ordinary (finite) cases. It is less than ideal in that undue overflow and underflow may occur.
}
}
return x + I * y;
- }</pre>
+ }
+</pre>
<p><!--para 9 -->
Scaling the denominator alleviates the main overflow and underflow problem, which is more serious than
for multiplication. In the spirit of the multiplication example above, this code does not defend against
In all cases the result and floating-point exception behavior of a + or - operator is defined
by the usual mathematical formula:
<pre>
- + or - u iv u + iv</pre>
+ + or - u iv u + iv
+</pre>
<pre>
- x x(+-)u x (+-) iv (x (+-) u) (+-) iv</pre>
+ x x(+-)u x (+-) iv (x (+-) u) (+-) iv
+</pre>
<pre>
- iy (+-)u + iy i(y (+-) v) (+-)u + i(y (+-) v)</pre>
+ iy (+-)u + iy i(y (+-) v) (+-)u + i(y (+-) v)
+</pre>
<pre>
- x + iy (x (+-) u) + iy x + i(y (+-) v) (x (+-) u) + i(y (+-) v)</pre>
+ x + iy (x (+-) u) + iy x + i(y (+-) v) (x (+-) u) + i(y (+-) v)
+</pre>
<h3><a name="G.6" href="#G.6">G.6 Complex arithmetic <complex.h></a></h3>
<p><!--para 1 -->
The macros
<pre>
- imaginary</pre>
+ imaginary
+</pre>
and
<pre>
- _Imaginary_I</pre>
+ _Imaginary_I
+</pre>
are defined, respectively, as _Imaginary and a constant expression of type const
float _Imaginary with the value of the imaginary unit. The macro
<pre>
- I</pre>
+ I
+</pre>
is defined to be _Imaginary_I (not _Complex_I as stated in <a href="#7.3">7.3</a>). Notwithstanding
the provisions of <a href="#7.1.3">7.1.3</a>, a program may undefine and then perhaps redefine the macro
imaginary.
function (whose special cases are covered in <a href="#F">annex F</a>):
<pre>
cabs(x + iy) = hypot(x, y)
- carg(x + iy) = atan2(y, x)</pre>
+ carg(x + iy) = atan2(y, x)
+</pre>
<p><!--para 7 -->
Each of the functions casin, catan, ccos, csin, and ctan is specified implicitly by
a formula in terms of other complex functions (whose special cases are specified below):
catan(z) = -i catanh(iz)
ccos(z) = ccosh(iz)
csin(z) = -i csinh(iz)
- ctan(z) = -i ctanh(iz)</pre>
+ ctan(z) = -i ctanh(iz)
+</pre>
<p><!--para 8 -->
For the other functions, the following subclauses specify behavior for special cases,
including treatment of the ''invalid'' and ''divide-by-zero'' floating-point exceptions. For
asin(iy) = i asinh(y)
atan(iy) = i atanh(y)
asinh(iy) = i asin(y)
- atanh(iy) = i atan(y)</pre>
+ atanh(iy) = i atan(y)
+</pre>
<h2><a name="H" href="#H">Annex H</a></h2>
<pre>
(informative)
- Language independent arithmetic</pre>
+ Language independent arithmetic
+</pre>
<h3><a name="H.1" href="#H.1">H.1 Introduction</a></h3>
<p><!--para 1 -->
The parameters for the integer data types can be accessed by the following:
maxint INT_MAX, LONG_MAX, LLONG_MAX, UINT_MAX, ULONG_MAX,
<pre>
- ULLONG_MAX</pre>
+ ULLONG_MAX
+</pre>
minint INT_MIN, LONG_MIN, LLONG_MIN
<p><!--para 3 -->
The parameter ''bounded'' is always true, and is not provided. The parameter ''minint''
exponentF 1.f+logbf(x), 1.0+logb(x), 1.L+logbl(x)
scaleF scalbnf(x, n), scalbn(x, n), scalbnl(x, n),
<pre>
- scalblnf(x, li), scalbln(x, li), scalblnl(x, li)</pre>
+ scalblnf(x, li), scalbln(x, li), scalblnl(x, li)
+</pre>
intpartF modff(x, &y), modf(x, &y), modfl(x, &y)
fractpartF modff(x, &y), modf(x, &y), modfl(x, &y)
eqF x == y
cvtI' -> I (int)i, (long int)i, (long long int)i,
<pre>
(unsigned int)i, (unsigned long int)i,
- (unsigned long long int)i</pre>
+ (unsigned long long int)i
+</pre>
cvtF -> I (int)x, (long int)x, (long long int)x,
<pre>
(unsigned int)x, (unsigned long int)x,
- (unsigned long long int)x</pre>
+ (unsigned long long int)x
+</pre>
cvtI -> F (float)i, (double)i, (long double)i
cvtF' -> F (float)x, (double)x, (long double)x
<p><!--para 2 -->
<h2><a name="I" href="#I">Annex I</a></h2>
<pre>
(informative)
- Common warnings</pre>
+ Common warnings
+</pre>
<p><!--para 1 -->
An implementation may generate warnings in many situations, none of which are
specified as part of this International Standard. The following are a few of the more
<h2><a name="J" href="#J">Annex J</a></h2>
<pre>
(informative)
- Portability issues</pre>
+ Portability issues
+</pre>
<p><!--para 1 -->
This annex collects some information about portability that appears in this International
Standard.
The asm keyword may be used to insert assembly language directly into the translator
output (<a href="#6.8">6.8</a>). The most common implementation is via a statement of the form:
<pre>
- asm ( character-string-literal );</pre>
+ asm ( character-string-literal );
+</pre>
<h4><a name="J.5.11" href="#J.5.11">J.5.11 Multiple external definitions</a></h4>
<p><!--para 1 -->
<h2><a name="K" href="#K">Annex K</a></h2>
<pre>
(normative)
- Bounds-checking interfaces</pre>
+ Bounds-checking interfaces
+</pre>
<h3><a name="K.1" href="#K.1">K.1 Background</a></h3>
<p><!--para 1 -->
<p><!--para 2 -->
The type is
<pre>
- errno_t</pre>
+ errno_t
+</pre>
which is type int.<sup><a href="#note371"><b>371)</b></a></sup>
<h6>footnotes</h6>
<p><!--para 2 -->
The type is
<pre>
- rsize_t</pre>
+ rsize_t
+</pre>
which is the type size_t.<sup><a href="#note372"><b>372)</b></a></sup>
<h6>footnotes</h6>
<p><!--para 2 -->
The macro is
<pre>
- RSIZE_MAX</pre>
+ RSIZE_MAX
+</pre>
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.
<p><!--para 2 -->
The macros are
<pre>
- L_tmpnam_s</pre>
+ L_tmpnam_s
+</pre>
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_s
function;
<pre>
- TMP_MAX_S</pre>
+ TMP_MAX_S
+</pre>
which expands to an integer constant expression that is the maximum number of unique
file names that can be generated by the tmpnam_s function.
<p><!--para 3 -->
The types are
<pre>
- errno_t</pre>
+ errno_t
+</pre>
which is type int; and
<pre>
- rsize_t</pre>
+ rsize_t
+</pre>
which is the type size_t.
<h5><a name="K.3.5.1" href="#K.3.5.1">K.3.5.1 Operations on files</a></h5>
<pre>
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
- errno_t tmpfile_s(FILE * restrict * restrict streamptr);</pre>
+ errno_t tmpfile_s(FILE * restrict * restrict streamptr);
+</pre>
Runtime-constraints
<p><!--para 2 -->
streamptr shall not be a null pointer.
<pre>
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
- errno_t tmpnam_s(char *s, rsize_t maxsize);</pre>
+ errno_t tmpnam_s(char *s, rsize_t maxsize);
+</pre>
Runtime-constraints
<p><!--para 2 -->
s shall not be a null pointer. maxsize shall be less than or equal to RSIZE_MAX.
#include <a href="#7.21"><stdio.h></a>
errno_t fopen_s(FILE * restrict * restrict streamptr,
const char * restrict filename,
- const char * restrict mode);</pre>
+ const char * restrict mode);
+</pre>
Runtime-constraints
<p><!--para 2 -->
None of streamptr, filename, or mode shall be a null pointer.
with the character 'w' or 'a' may be preceded by the character 'u', see below:
uw truncate to zero length or create text file for writing, default
<pre>
- permissions</pre>
+ permissions
+</pre>
uwx create text file for writing, default permissions
ua append; open or create text file for writing at end-of-file, default
<pre>
- permissions</pre>
+ permissions
+</pre>
uwb truncate to zero length or create binary file for writing, default
<pre>
- permissions</pre>
+ permissions
+</pre>
uwbx create binary file for writing, default permissions
uab append; open or create binary file for writing at end-of-file, default
<pre>
- permissions</pre>
+ permissions
+</pre>
uw+ truncate to zero length or create text file for update, default
<pre>
- permissions</pre>
+ permissions
+</pre>
uw+x create text file for update, default permissions
ua+ append; open or create text file for update, writing at end-of-file,
<pre>
- default permissions</pre>
+ default permissions
+</pre>
uw+b or uwb+ truncate to zero length or create binary file for update, default
<pre>
- permissions</pre>
+ permissions
+</pre>
uw+bx or uwb+x create binary file for update, default permissions
ua+b or uab+ append; open or create binary file for update, writing at end-of-file,
<pre>
- default permissions</pre>
+ default permissions
+</pre>
<p><!--para 6 -->
Opening a file with exclusive mode ('x' as the last character in the mode argument)
fails if the file already exists or cannot be created.
errno_t freopen_s(FILE * restrict * restrict newstreamptr,
const char * restrict filename,
const char * restrict mode,
- FILE * restrict stream);</pre>
+ FILE * restrict stream);
+</pre>
Runtime-constraints
<p><!--para 2 -->
None of newstreamptr, mode, and stream shall be a null pointer.
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
int fprintf_s(FILE * restrict stream,
- const char * restrict format, ...);</pre>
+ const char * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither stream nor format shall be a null pointer. The %n specifier<sup><a href="#note377"><b>377)</b></a></sup> (modified or
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
int fscanf_s(FILE * restrict stream,
- const char * restrict format, ...);</pre>
+ const char * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither stream nor format shall be a null pointer. Any argument indirected though in
#include <a href="#7.21"><stdio.h></a>
/* ... */
int n, i; float x; char name[50];
- n = fscanf_s(stdin, "%d%f%s", &i, &x, name, (rsize_t) 50);</pre>
+ n = fscanf_s(stdin, "%d%f%s", &i, &x, name, (rsize_t) 50);
+</pre>
with the input line:
<pre>
- 25 54.32E-1 thompson</pre>
+ 25 54.32E-1 thompson
+</pre>
will assign to n the value 3, to i the value 25, to x the value 5.432, and to name the sequence
thompson\0.
#include <a href="#7.21"><stdio.h></a>
/* ... */
int n; char s[5];
- n = fscanf_s(stdin, "%s", s, sizeof s);</pre>
+ n = fscanf_s(stdin, "%s", s, sizeof s);
+</pre>
with the input line:
<pre>
- hello</pre>
+ hello
+</pre>
will assign to n the value 0 since a matching failure occurred because the sequence hello\0 requires an
array of six characters to store it.
<pre>
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
- int printf_s(const char * restrict format, ...);</pre>
+ int printf_s(const char * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 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
<pre>
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
- int scanf_s(const char * restrict format, ...);</pre>
+ int scanf_s(const char * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 2 -->
format shall not be a null pointer. Any argument indirected though in order to store
#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, ...);</pre>
+ const char * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
int sprintf_s(char * restrict s, rsize_t n,
- const char * restrict format, ...);</pre>
+ const char * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
int sscanf_s(const char * restrict s,
- const char * restrict format, ...);</pre>
+ const char * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor format shall be a null pointer. Any argument indirected though in order
#include <a href="#7.21"><stdio.h></a>
int vfprintf_s(FILE * restrict stream,
const char * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither stream nor format shall be a null pointer. The %n specifier<sup><a href="#note384"><b>384)</b></a></sup> (modified or
#include <a href="#7.21"><stdio.h></a>
int vfscanf_s(FILE * restrict stream,
const char * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
#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);</pre>
+ va_list arg);
+</pre>
Runtime-constraints
<p><!--para 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
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.21"><stdio.h></a>
int vscanf_s(const char * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
Runtime-constraints
<p><!--para 2 -->
format shall not be a null pointer. Any argument indirected though in order to store
#include <a href="#7.21"><stdio.h></a>
int vsnprintf_s(char * restrict s, rsize_t n,
const char * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
#include <a href="#7.21"><stdio.h></a>
int vsprintf_s(char * restrict s, rsize_t n,
const char * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
#include <a href="#7.21"><stdio.h></a>
int vsscanf_s(const char * restrict s,
const char * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor format shall be a null pointer. Any argument indirected though in order
<pre>
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.21"><stdio.h></a>
- char *gets_s(char *s, rsize_t n);</pre>
+ char *gets_s(char *s, rsize_t n);
+</pre>
<p><!--para 2 -->
The types are
<pre>
- errno_t</pre>
+ errno_t
+</pre>
which is type int; and
<pre>
- rsize_t</pre>
+ rsize_t
+</pre>
which is the type size_t; and
<pre>
- constraint_handler_t</pre>
+ constraint_handler_t
+</pre>
which has the following definition
<pre>
typedef void (*constraint_handler_t)(
const char * restrict msg,
void * restrict ptr,
- errno_t error);</pre>
+ errno_t error);
+</pre>
<h5><a name="K.3.6.1" href="#K.3.6.1">K.3.6.1 Runtime-constraint handling</a></h5>
#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);</pre>
+ constraint_handler_t handler);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The set_constraint_handler_s function sets the runtime-constraint handler to
void abort_handler_s(
const char * restrict msg,
void * restrict ptr,
- errno_t error);</pre>
+ errno_t error);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
A pointer to the abort_handler_s function shall be a suitable argument to the
void ignore_handler_s(
const char * restrict msg,
void * restrict ptr,
- errno_t error);</pre>
+ errno_t error);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
A pointer to the ignore_handler_s function shall be a suitable argument to the
#include <a href="#7.22"><stdlib.h></a>
errno_t getenv_s(size_t * restrict len,
char * restrict value, rsize_t maxsize,
- const char * restrict name);</pre>
+ const char * restrict name);
+</pre>
Runtime-constraints
<p><!--para 2 -->
name shall not be a null pointer. maxsize shall neither equal zero nor be greater than
<pre>
((char *)p - (char *)base) % size == 0
(char *)p >= (char *)base
- (char *)p < (char *)base + nmemb * size</pre>
+ (char *)p < (char *)base + nmemb * size
+</pre>
</small>
<h5><a name="K.3.6.3.1" href="#K.3.6.3.1">K.3.6.3.1 The bsearch_s function</a></h5>
rsize_t nmemb, rsize_t size,
int (*compar)(const void *k, const void *y,
void *context),
- void *context);</pre>
+ void *context);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither nmemb nor size shall be greater than RSIZE_MAX. If nmemb is not equal to
errno_t qsort_s(void *base, rsize_t nmemb, rsize_t size,
int (*compar)(const void *x, const void *y,
void *context),
- void *context);</pre>
+ void *context);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither nmemb nor size shall be greater than RSIZE_MAX. If nmemb is not equal to
errno_t wctomb_s(int * restrict status,
char * restrict s,
rsize_t smax,
- wchar_t wc);</pre>
+ wchar_t wc);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Let n denote the number of bytes needed to represent the multibyte character
#include <a href="#7.22"><stdlib.h></a>
errno_t mbstowcs_s(size_t * restrict retval,
wchar_t * restrict dst, rsize_t dstmax,
- const char * restrict src, rsize_t len);</pre>
+ const char * restrict src, rsize_t len);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither retval nor src shall be a null pointer. If dst is not a null pointer, then
#include <a href="#7.22"><stdlib.h></a>
errno_t wcstombs_s(size_t * restrict retval,
char * restrict dst, rsize_t dstmax,
- const wchar_t * restrict src, rsize_t len);</pre>
+ const wchar_t * restrict src, rsize_t len);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither retval nor src shall be a null pointer. If dst is not a null pointer, then
<p><!--para 2 -->
The types are
<pre>
- errno_t</pre>
+ errno_t
+</pre>
which is type int; and
<pre>
- rsize_t</pre>
+ rsize_t
+</pre>
which is the type size_t.
<h5><a name="K.3.7.1" href="#K.3.7.1">K.3.7.1 Copying functions</a></h5>
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
errno_t memcpy_s(void * restrict s1, rsize_t s1max,
- const void * restrict s2, rsize_t n);</pre>
+ const void * restrict s2, rsize_t n);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s1 nor s2 shall be a null pointer. Neither s1max nor n shall be greater than
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
errno_t memmove_s(void *s1, rsize_t s1max,
- const void *s2, rsize_t n);</pre>
+ const void *s2, rsize_t n);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s1 nor s2 shall be a null pointer. Neither s1max nor n shall be greater than
#include <a href="#7.23"><string.h></a>
errno_t strcpy_s(char * restrict s1,
rsize_t s1max,
- const char * restrict s2);</pre>
+ const char * restrict s2);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s1 nor s2 shall be a null pointer. s1max shall not be greater than RSIZE_MAX.
errno_t strncpy_s(char * restrict s1,
rsize_t s1max,
const char * restrict s2,
- rsize_t n);</pre>
+ rsize_t n);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s1 nor s2 shall be a null pointer. Neither s1max nor n shall be greater than
int r1, r2, r3;
r1 = strncpy_s(dst1, 6, src1, 100);
r2 = strncpy_s(dst2, 5, src2, 7);
- r3 = strncpy_s(dst3, 5, src2, 4);</pre>
+ r3 = strncpy_s(dst3, 5, src2, 4);
+</pre>
The first call will assign to r1 the value zero and to dst1 the sequence hello\0.
The second call will assign to r2 a nonzero value and to dst2 the sequence \0.
The third call will assign to r3 the value zero and to dst3 the sequence good\0.
#include <a href="#7.23"><string.h></a>
errno_t strcat_s(char * restrict s1,
rsize_t s1max,
- const char * restrict s2);</pre>
+ const char * restrict s2);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Let m denote the value s1max - strnlen_s(s1, s1max) upon entry to
errno_t strncat_s(char * restrict s1,
rsize_t s1max,
const char * restrict s2,
- rsize_t n);</pre>
+ rsize_t n);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Let m denote the value s1max - strnlen_s(s1, s1max) upon entry to
r1 = strncat_s(s1, 100, s5, 1000);
r2 = strncat_s(s2, 6, "", 1);
r3 = strncat_s(s3, 6, "X", 2);
- r4 = strncat_s(s4, 7, "defghijklmn", 3);</pre>
+ r4 = strncat_s(s4, 7, "defghijklmn", 3);
+</pre>
After the first call r1 will have the value zero and s1 will contain the sequence goodbye\0.
char *strtok_s(char * restrict s1,
rsize_t * restrict s1max,
const char * restrict s2,
- char ** restrict ptr);</pre>
+ char ** restrict ptr);
+</pre>
Runtime-constraints
<p><!--para 2 -->
None of s1max, s2, or ptr shall be a null pointer. If s1 is a null pointer, then *ptr
t = strtok_s(NULL, &max1, ",", &ptr1); // t points to the token "??b"
t = strtok_s(str2, &max2, " \t", &ptr2); // t is a null pointer
t = strtok_s(NULL, &max1, "#,", &ptr1); // t points to the token "c"
- t = strtok_s(NULL, &max1, "?", &ptr1); // t is a null pointer</pre>
+ t = strtok_s(NULL, &max1, "?", &ptr1); // t is a null pointer
+</pre>
<h5><a name="K.3.7.4" href="#K.3.7.4">K.3.7.4 Miscellaneous functions</a></h5>
<pre>
#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)</pre>
+ errno_t memset_s(void *s, rsize_t smax, int c, rsize_t n)
+</pre>
Runtime-constraints
<p><!--para 2 -->
s shall not be a null pointer. Neither smax nor n shall be greater than RSIZE_MAX. n
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
errno_t strerror_s(char *s, rsize_t maxsize,
- errno_t errnum);</pre>
+ errno_t errnum);
+</pre>
Runtime-constraints
<p><!--para 2 -->
s shall not be a null pointer. maxsize shall not be greater than RSIZE_MAX.
<pre>
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
- size_t strerrorlen_s(errno_t errnum);</pre>
+ size_t strerrorlen_s(errno_t errnum);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strerrorlen_s function calculates the length of the (untruncated) locale-specific
<pre>
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.23"><string.h></a>
- size_t strnlen_s(const char *s, size_t maxsize);</pre>
+ size_t strnlen_s(const char *s, size_t maxsize);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The strnlen_s function computes the length of the string pointed to by s.
<p><!--para 2 -->
The types are
<pre>
- errno_t</pre>
+ errno_t
+</pre>
which is type int; and
<pre>
- rsize_t</pre>
+ rsize_t
+</pre>
which is the type size_t.
<h5><a name="K.3.8.1" href="#K.3.8.1">K.3.8.1 Components of time</a></h5>
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.26"><time.h></a>
errno_t asctime_s(char *s, rsize_t maxsize,
- const struct tm *timeptr);</pre>
+ const struct tm *timeptr);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor timeptr shall be a null pointer. maxsize shall not be less than 26 and
<!--page 639 -->
form
<pre>
- Sun Sep 16 01:03:52 1973\n\0</pre>
+ Sun Sep 16 01:03:52 1973\n\0
+</pre>
The fields making up this string are (in order):
<ol>
<li> The name of the day of the week represented by timeptr->tm_wday using the
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.26"><time.h></a>
errno_t ctime_s(char *s, rsize_t maxsize,
- const time_t *timer);</pre>
+ const time_t *timer);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor timer shall be a null pointer. maxsize shall not be less than 26 and
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
<pre>
- asctime_s(s, maxsize, localtime_s(timer))</pre>
+ asctime_s(s, maxsize, localtime_s(timer))
+</pre>
<h6>Recommended practice</h6>
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
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.26"><time.h></a>
struct tm *gmtime_s(const time_t * restrict timer,
- struct tm * restrict result);</pre>
+ struct tm * restrict result);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither timer nor result shall be a null pointer.
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.26"><time.h></a>
struct tm *localtime_s(const time_t * restrict timer,
- struct tm * restrict result);</pre>
+ struct tm * restrict result);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither timer nor result shall be a null pointer.
<p><!--para 2 -->
The types are
<pre>
- errno_t</pre>
+ errno_t
+</pre>
which is type int; and
<pre>
- rsize_t</pre>
+ rsize_t
+</pre>
which is the type size_t.
<p><!--para 3 -->
Unless explicitly stated otherwise, if the execution of a function described in this
#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, ...);</pre>
+ const wchar_t * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither stream nor format shall be a null pointer. The %n specifier<sup><a href="#note416"><b>416)</b></a></sup> (modified or
#include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
int fwscanf_s(FILE * restrict stream,
- const wchar_t * restrict format, ...);</pre>
+ const wchar_t * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither stream nor format shall be a null pointer. Any argument indirected though in
#include <a href="#7.28"><wchar.h></a>
int snwprintf_s(wchar_t * restrict s,
rsize_t n,
- const wchar_t * restrict format, ...);</pre>
+ const wchar_t * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
int swprintf_s(wchar_t * restrict s, rsize_t n,
- const wchar_t * restrict format, ...);</pre>
+ const wchar_t * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
int swscanf_s(const wchar_t * restrict s,
- const wchar_t * restrict format, ...);</pre>
+ const wchar_t * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor format shall be a null pointer. Any argument indirected though in order
#include <a href="#7.28"><wchar.h></a>
int vfwprintf_s(FILE * restrict stream,
const wchar_t * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither stream nor format shall be a null pointer. The %n specifier<sup><a href="#note420"><b>420)</b></a></sup> (modified or
#include <a href="#7.21"><stdio.h></a>
#include <a href="#7.28"><wchar.h></a>
int vfwscanf_s(FILE * restrict stream,
- const wchar_t * restrict format, va_list arg);</pre>
+ const wchar_t * restrict format, va_list arg);
+</pre>
int vsnwprintf_s(wchar_t * restrict s,
rsize_t n,
const wchar_t * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
int vswprintf_s(wchar_t * restrict s,
rsize_t n,
const wchar_t * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor format shall be a null pointer. n shall neither equal zero nor be greater
#include <a href="#7.28"><wchar.h></a>
int vswscanf_s(const wchar_t * restrict s,
const wchar_t * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s nor format shall be a null pointer. Any argument indirected though in order
#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);</pre>
+ va_list arg);
+</pre>
Runtime-constraints
<p><!--para 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
#include <a href="#7.16"><stdarg.h></a>
#include <a href="#7.28"><wchar.h></a>
int vwscanf_s(const wchar_t * restrict format,
- va_list arg);</pre>
+ va_list arg);
+</pre>
Runtime-constraints
<p><!--para 2 -->
format shall not be a null pointer. Any argument indirected though in order to store
<pre>
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
- int wprintf_s(const wchar_t * restrict format, ...);</pre>
+ int wprintf_s(const wchar_t * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 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
<pre>
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
- int wscanf_s(const wchar_t * restrict format, ...);</pre>
+ int wscanf_s(const wchar_t * restrict format, ...);
+</pre>
Runtime-constraints
<p><!--para 2 -->
format shall not be a null pointer. Any argument indirected though in order to store
#include <a href="#7.28"><wchar.h></a>
errno_t wcscpy_s(wchar_t * restrict s1,
rsize_t s1max,
- const wchar_t * restrict s2);</pre>
+ const wchar_t * restrict s2);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Neither s1 nor s2 shall be a null pointer. s1max shall not be greater than RSIZE_MAX.
errno_t wcsncpy_s(wchar_t * restrict s1,
rsize_t s1max,
const wchar_t * restrict s2,
- rsize_t n);</pre>
+ rsize_t n);
+</pre>
Runtime-constraints
<p><!--para 8 -->
Neither s1 nor s2 shall be a null pointer. Neither s1max nor n shall be greater than
int r1, r2, r3;
r1 = wcsncpy_s(dst1, 6, src1, 100);
r2 = wcsncpy_s(dst2, 5, src2, 7);
- r3 = wcsncpy_s(dst3, 5, src2, 4);</pre>
+ r3 = wcsncpy_s(dst3, 5, src2, 4);
+</pre>
The first call will assign to r1 the value zero and to dst1 the sequence of wide characters hello\0.
The second call will assign to r2 a nonzero value and to dst2 the sequence of wide characters \0.
The third call will assign to r3 the value zero and to dst3 the sequence of wide characters good\0.
errno_t wmemcpy_s(wchar_t * restrict s1,
rsize_t s1max,
const wchar_t * restrict s2,
- rsize_t n);</pre>
+ rsize_t n);
+</pre>
Runtime-constraints
<p><!--para 15 -->
Neither s1 nor s2 shall be a null pointer. Neither s1max nor n shall be greater than
#define __STDC_WANT_LIB_EXT1__ 1
#include <a href="#7.28"><wchar.h></a>
errno_t wmemmove_s(wchar_t *s1, rsize_t s1max,
- const wchar_t *s2, rsize_t n);</pre>
+ const wchar_t *s2, rsize_t n);
+</pre>
Runtime-constraints
<p><!--para 20 -->
Neither s1 nor s2 shall be a null pointer. Neither s1max nor n shall be greater than
#include <a href="#7.28"><wchar.h></a>
errno_t wcscat_s(wchar_t * restrict s1,
rsize_t s1max,
- const wchar_t * restrict s2);</pre>
+ const wchar_t * restrict s2);
+</pre>
Runtime-constraints
<p><!--para 2 -->
Let m denote the value s1max - wcsnlen_s(s1, s1max) upon entry to
errno_t wcsncat_s(wchar_t * restrict s1,
rsize_t s1max,
const wchar_t * restrict s2,
- rsize_t n);</pre>
+ rsize_t n);
+</pre>
Runtime-constraints
<p><!--para 9 -->
Let m denote the value s1max - wcsnlen_s(s1, s1max) upon entry to
r1 = wcsncat_s(s1, 100, s5, 1000);
r2 = wcsncat_s(s2, 6, L"", 1);
r3 = wcsncat_s(s3, 6, L"X", 2);
- r4 = wcsncat_s(s4, 7, L"defghijklmn", 3);</pre>
+ r4 = wcsncat_s(s4, 7, L"defghijklmn", 3);
+</pre>
After the first call r1 will have the value zero and s1 will be the wide character sequence goodbye\0.
After the second call r2 will have the value zero and s2 will be the wide character sequence hello\0.
After the third call r3 will have a nonzero value and s3 will be the wide character sequence \0.
wchar_t *wcstok_s(wchar_t * restrict s1,
rsize_t * restrict s1max,
const wchar_t * restrict s2,
- wchar_t ** restrict ptr);</pre>
+ wchar_t ** restrict ptr);
+</pre>
Runtime-constraints
<p><!--para 2 -->
None of s1max, s2, or ptr shall be a null pointer. If s1 is a null pointer, then *ptr
t = wcstok_s(NULL, &max1, ",", &ptr1); // t points to the token "??b"
t = wcstok_s(str2, &max2, " \t", &ptr2); // t is a null pointer
t = wcstok_s(NULL, &max1, "#,", &ptr1); // t points to the token "c"
- t = wcstok_s(NULL, &max1, "?", &ptr1); // t is a null pointer</pre>
+ t = wcstok_s(NULL, &max1, "?", &ptr1); // t is a null pointer
+</pre>
<h5><a name="K.3.9.2.4" href="#K.3.9.2.4">K.3.9.2.4 Miscellaneous functions</a></h5>
<pre>
#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);</pre>
+ size_t wcsnlen_s(const wchar_t *s, size_t maxsize);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The wcsnlen_s function computes the length of the wide string pointed to by s.
#include <a href="#7.28"><wchar.h></a>
errno_t wcrtomb_s(size_t * restrict retval,
char * restrict s, rsize_t smax,
- wchar_t wc, mbstate_t * restrict ps);</pre>
+ wchar_t wc, mbstate_t * restrict ps);
+</pre>
Runtime-constraints
<p><!--para 3 -->
Neither retval nor ps shall be a null pointer. If s is not a null pointer, then smax
<p><!--para 5 -->
If s is a null pointer, the wcrtomb_s function is equivalent to the call
<pre>
- wcrtomb_s(&retval, buf, sizeof buf, L'\0', ps)</pre>
+ wcrtomb_s(&retval, buf, sizeof buf, L'\0', ps)
+</pre>
where retval and buf are internal variables of the appropriate types, and the size of
buf is greater than MB_CUR_MAX.
<p><!--para 6 -->
errno_t mbsrtowcs_s(size_t * restrict retval,
wchar_t * restrict dst, rsize_t dstmax,
const char ** restrict src, rsize_t len,
- mbstate_t * restrict ps);</pre>
+ mbstate_t * restrict ps);
+</pre>
Runtime-constraints
<p><!--para 3 -->
None of retval, src, *src, or ps shall be null pointers. If dst is not a null pointer,
errno_t wcsrtombs_s(size_t * restrict retval,
char * restrict dst, rsize_t dstmax,
const wchar_t ** restrict src, rsize_t len,
- mbstate_t * restrict ps);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h2><a name="L" href="#L">Annex L</a></h2>
<pre>
(normative)
- Analyzability</pre>
+ Analyzability
+</pre>
<h3><a name="L.1" href="#L.1">L.1 Scope</a></h3>
<p><!--para 1 -->
projects / c-standard / blobdiff