<html><head><title>WG14/N1256 Septermber 7, 2007 ISO/IEC 9899:TC3</title></head><body>
-<pre><!--page 1 -->
+<pre>
+<!--page 1 -->
WG14/N1256 Committee Draft -- Septermber 7, 2007 ISO/IEC 9899:TC3
/* ... */
fesetround(FE_UPWARD);
/* ... */
- #endif</pre>
+ #endif
+</pre>
</small>
<p><small><a name="note3" href="#note3">3)</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="#note9"><b>9)</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 13 -->
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 14 -->
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
<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>
(absolute value) to those shown, with the same sign.
<ul>
<li> number of bits for smallest object that is not a bit-field (byte)
-<pre> CHAR_BIT 8</pre>
+<pre>
+ CHAR_BIT 8
+</pre>
<li> minimum value for an object of type signed char
-<pre> SCHAR_MIN -127 // -(2<sup>7</sup> - 1)</pre>
+<pre>
+ SCHAR_MIN -127 // -(2<sup>7</sup> - 1)
+</pre>
<li> maximum value for an object of type signed char
-<pre> SCHAR_MAX +127 // 2<sup>7</sup> - 1</pre>
+<pre>
+ SCHAR_MAX +127 // 2<sup>7</sup> - 1
+</pre>
<li> maximum value for an object of type unsigned char
-<pre> UCHAR_MAX 255 // 2<sup>8</sup> - 1</pre>
+<pre>
+ UCHAR_MAX 255 // 2<sup>8</sup> - 1
+</pre>
<li> minimum value for an object of type char
-<pre> CHAR_MIN see below</pre>
+<pre>
+ CHAR_MIN see below
+</pre>
<li> maximum value for an object of type char
-<pre> CHAR_MAX see below</pre>
+<pre>
+ CHAR_MAX see below
+</pre>
<li> maximum number of bytes in a multibyte character, for any supported locale
-<pre> MB_LEN_MAX 1</pre>
+<pre>
+ MB_LEN_MAX 1
+</pre>
<li> minimum value for an object of type short int
-<pre> SHRT_MIN -32767 // -(2<sup>15</sup> - 1)</pre>
+<pre>
+ SHRT_MIN -32767 // -(2<sup>15</sup> - 1)
+</pre>
<li> maximum value for an object of type short int
-<pre> SHRT_MAX +32767 // 2<sup>15</sup> - 1</pre>
+<pre>
+ SHRT_MAX +32767 // 2<sup>15</sup> - 1
+</pre>
<li> maximum value for an object of type unsigned short int
-<pre> USHRT_MAX 65535 // 2<sup>16</sup> - 1</pre>
+<pre>
+ USHRT_MAX 65535 // 2<sup>16</sup> - 1
+</pre>
<li> minimum value for an object of type int
-<pre> INT_MIN -32767 // -(2<sup>15</sup> - 1)</pre>
+<pre>
+ INT_MIN -32767 // -(2<sup>15</sup> - 1)
+</pre>
<li> maximum value for an object of type int
-<pre> INT_MAX +32767 // 2<sup>15</sup> - 1</pre>
+<pre>
+ INT_MAX +32767 // 2<sup>15</sup> - 1
+</pre>
<li> maximum value for an object of type unsigned int
-<pre> UINT_MAX 65535 // 2<sup>16</sup> - 1</pre>
+<pre>
+ UINT_MAX 65535 // 2<sup>16</sup> - 1
+</pre>
<li> minimum value for an object of type long int
-<pre> LONG_MIN -2147483647 // -(2<sup>31</sup> - 1)</pre>
+<pre>
+ LONG_MIN -2147483647 // -(2<sup>31</sup> - 1)
+</pre>
<li> maximum value for an object of type long int
-<pre> LONG_MAX +2147483647 // 2<sup>31</sup> - 1</pre>
+<pre>
+ LONG_MAX +2147483647 // 2<sup>31</sup> - 1
+</pre>
<li> maximum value for an object of type unsigned long int
-<pre> ULONG_MAX 4294967295 // 2<sup>32</sup> - 1</pre>
+<pre>
+ ULONG_MAX 4294967295 // 2<sup>32</sup> - 1
+</pre>
<!--page 35 -->
<li> minimum value for an object of type long long int
-<pre> LLONG_MIN -9223372036854775807 // -(2<sup>63</sup> - 1)</pre>
+<pre>
+ LLONG_MIN -9223372036854775807 // -(2<sup>63</sup> - 1)
+</pre>
<li> maximum value for an object of type long long int
-<pre> LLONG_MAX +9223372036854775807 // 2<sup>63</sup> - 1</pre>
+<pre>
+ LLONG_MAX +9223372036854775807 // 2<sup>63</sup> - 1
+</pre>
<li> maximum value for an object of type unsigned long long int
-<pre> ULLONG_MAX 18446744073709551615 // 2<sup>64</sup> - 1</pre>
+<pre>
+ ULLONG_MAX 18446744073709551615 // 2<sup>64</sup> - 1
+</pre>
</ul>
<p><!--para 2 -->
If the value of an object of type char is treated as a signed integer when used in an
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)
- f<sub>k</sub> nonnegative integers less than b (the significand digits)</pre>
+ f<sub>k</sub> nonnegative integers less than b (the significand digits)
+</pre>
A floating-point number (x) is defined by the following model:
<pre>
p
x = s b<sup>e</sup> (Sum) f<sub>k</sub> b<sup>-k</sup> , emin <= e <= emax
- k=1</pre>
+ k=1
+</pre>
<p><!--para 3 -->
In addition to normalized floating-point numbers ( f<sub>1</sub> > 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.
<p><!--para 8 -->
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 9 -->
those shown, with the same sign:
<ul>
<li> radix of exponent representation, b
-<pre> FLT_RADIX 2</pre>
+<pre>
+ FLT_RADIX 2
+</pre>
<li> number of base-FLT_RADIX digits in the floating-point significand, p
-<pre> FLT_MANT_DIG
+<pre>
+ FLT_MANT_DIG
DBL_MANT_DIG
- LDBL_MANT_DIG</pre>
+ LDBL_MANT_DIG
+</pre>
<li> number of decimal digits, n, such that any floating-point number in the widest
supported floating type with pmax radix b digits can be rounded to a floating-point
number with n decimal digits and back again without change to the value,
<pre>
{ pmax log10 b if b is a power of 10
{
- { [^1 + pmax log10 b^] otherwise</pre>
-<pre> DECIMAL_DIG 10</pre>
+ { [^1 + pmax log10 b^] otherwise
+</pre>
+<pre>
+ DECIMAL_DIG 10
+</pre>
<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
without change to the q decimal digits,
<pre>
{ p log10 b if b is a power of 10
{
- { [_( p - 1) log10 b_] otherwise</pre>
-<pre> FLT_DIG 6
+ { [_( p - 1) log10 b_] otherwise
+</pre>
+<pre>
+ FLT_DIG 6
DBL_DIG 10
- LDBL_DIG 10</pre>
+ LDBL_DIG 10
+</pre>
<li> minimum negative integer such that FLT_RADIX raised to one less than that power is
a normalized floating-point number, emin
-<pre> FLT_MIN_EXP
+<pre>
+ FLT_MIN_EXP
DBL_MIN_EXP
- LDBL_MIN_EXP</pre>
+ LDBL_MIN_EXP
+</pre>
<li> minimum negative integer such that 10 raised to that power is in the range of
normalized floating-point numbers, [^log10 b<sup>emin -1</sup>^]
-<pre> FLT_MIN_10_EXP -37
+<pre>
+ FLT_MIN_10_EXP -37
DBL_MIN_10_EXP -37
- LDBL_MIN_10_EXP -37</pre>
+ LDBL_MIN_10_EXP -37
+</pre>
<li> maximum integer such that FLT_RADIX raised to one less than that power is a
representable finite floating-point number, emax
-<pre> FLT_MAX_EXP
+<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<sup>-p</sup>)b<sup>emax</sup>)_]
-<pre> FLT_MAX_10_EXP +37
+<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 10 -->
The values given in the following list shall be replaced by constant expressions with
implementation-defined values that are greater than or equal to those shown:
<ul>
<li> maximum representable finite floating-point number, (1 - b<sup>-p</sup>)b<sup>emax</sup>
-<pre> FLT_MAX 1E+37
+<pre>
+ FLT_MAX 1E+37
DBL_MAX 1E+37
- LDBL_MAX 1E+37</pre>
+ LDBL_MAX 1E+37
+</pre>
</ul>
<p><!--para 11 -->
The values given in the following list shall be replaced by constant expressions with
<li> the difference between 1 and the least value greater than 1 that is representable in the
given floating point type, b<sup>1-p</sup>
<!--page 39 -->
-<pre> FLT_EPSILON 1E-5
+<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<sup>emin -1</sup>
-<pre> FLT_MIN 1E-37
+<pre>
+ FLT_MIN 1E-37
DBL_MIN 1E-37
- LDBL_MIN 1E-37</pre>
+ LDBL_MIN 1E-37
+</pre>
</ul>
-<h6> Recommended practice</h6>
+<h6>Recommended practice</h6>
<p><!--para 12 -->
Conversion from (at least) double to decimal with DECIMAL_DIG digits and back
should be the identity function.
<pre>
6
x = s 16<sup>e</sup> (Sum) f<sub>k</sub> 16<sup>-k</sup> , -31 <= e <= +32
- k=1</pre>
+ k=1
+</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 14 -->
EXAMPLE 2 The following describes floating-point representations that also meet the requirements for
<pre>
24
xf = s 2<sup>e</sup> (Sum) f<sub>k</sub> 2<sup>-k</sup> , -125 <= e <= +128
- k=1</pre>
+ k=1
+</pre>
<pre>
53
xd = s 2<sup>e</sup> (Sum) f<sub>k</sub> 2<sup>-k</sup> , -1021 <= e <= +1024
- k=1</pre>
+ k=1
+</pre>
<pre>
DECIMAL_DIG 17
FLT_MANT_DIG 24
FLT_EPSILON 1.19209290E-07F // decimal constant
- FLT_EPSILON 0X1P-23F // hex constant</pre>
+ FLT_EPSILON 0X1P-23F // hex constant
+</pre>
<!--page 40 -->
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
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:
<!--page 54 -->
<pre>
- int f(int (*)(char *), double (*)[3]);</pre>
+ int f(int (*)(char *), double (*)[3]);
+</pre>
<h6>footnotes</h6>
<p><small><a name="note46" href="#note46">46)</a> Two types need not be identical to be compatible.
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
default inline struct _Imaginary
do int switch
double long typedef
- else register union</pre>
+ else register union
+</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
<!--page 64 -->
-<h6> Implementation limits</h6>
+<h6>Implementation limits</h6>
<p><!--para 5 -->
As discussed in <a href="#5.2.4.1">5.2.4.1</a>, an implementation may limit the number of significant initial
characters in an identifier; the limit for an external name (an identifier that has external
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="#note61"><b>61)</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
<table border=1>
<tr><th> Suffix <th>Decimal Constant <th>Octal or Hexadecimal Constant
<tr><td> none
-<td><pre>int
+<td><pre>
+int
long int
-long long int</pre>
-<td><pre>int
+long long int
+</pre>
+<td><pre>
+int
unsigned int
long int
unsigned long int
long long int
-unsigned long long int</pre>
+unsigned long long int
+</pre>
<tr><td> u or U
-<td><pre>unsigned int
+<td><pre>
+unsigned int
unsigned long int
-unsigned long long int</pre>
-<td><pre>unsigned int
+unsigned long long int
+</pre>
+<td><pre>
+unsigned int
unsigned long int
-unsigned long long int</pre>
+unsigned long long int
+</pre>
<tr><td> l or L
-<td><pre>long int
-long long int</pre>
-<td><pre>long int
+<td><pre>
+long int
+long long int
+</pre>
+<td><pre>
+long int
unsigned long int
long long int
-unsigned long long int</pre>
+unsigned long long int
+</pre>
<tr><td> Both u or U and l or L
-<td><pre>unsigned long int
-unsigned long long int</pre>
-<td><pre>unsigned long int
-unsigned long long int</pre>
+<td><pre>
+unsigned long int
+unsigned long long int
+</pre>
+<td><pre>
+unsigned long int
+unsigned long long int
+</pre>
<tr><td> ll or LL
-<td><pre>long long int</pre>
-<td><pre>long long int
-unsigned long long int</pre>
+<td><pre>
+long long int
+</pre>
+<td><pre>
+long long int
+unsigned long long int
+</pre>
<tr><td> Both u or U and ll or LL
-<td><pre>unsigned long long int</pre>
-<td><pre>unsigned long long int</pre>
+<td><pre>
+unsigned long long int
+</pre>
+<td><pre>
+unsigned long long int
+</pre>
</table>
<p><!--para 6 -->
If an integer constant cannot be represented by any type in its list, it may have an
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>
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 \
shall be represented, respectively, by the escape sequences \' and \\.
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>Description</h6>
<p><!--para 2 -->
A character string literal is a sequence of zero or more multibyte characters enclosed in
<p><!--para 7 -->
EXAMPLE 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.
? : ; ...
= *= /= %= += -= <<= >>= &= ^= |=
, # ##
- <: :> <% %> %: %:%:</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="#note67"><b>67)</b></a></sup>
<pre>
- <: :> <% %> %: %:%:</pre>
+ <: :> <% %> %: %:%:
+</pre>
behave, respectively, the same as the six tokens
<pre>
- [ ] { } # ##</pre>
+ [ ] { } # ##
+</pre>
except for their spelling.<sup><a href="#note68"><b>68)</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="note74" href="#note74">74)</a> The syntax specifies the precedence of operators in the evaluation of an expression, which is the same
identifier
constant
string-literal
- ( expression )</pre>
+ ( expression )
+</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
An identifier is a primary expression, provided it has been declared as designating an
postfix-expression ++
postfix-expression --
( type-name ) { initializer-list }
- ( type-name ) { initializer-list , }</pre>
+ ( type-name ) { initializer-list , }
+</pre>
<pre>
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>).
<p><!--para 9 -->
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:
<pre>
drawline(&(struct point){.x=1, .y=1},
- &(struct point){.x=3, .y=4});</pre>
+ &(struct point){.x=3, .y=4});
+</pre>
<p><!--para 12 -->
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>
<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 15 -->
<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 16 -->
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 17 -->
Note that if an iteration statement were used instead of an explicit goto and a labeled statement, the
sizeof unary-expression
sizeof ( 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 6 -->
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 7 -->
EXAMPLE 3 In this example, the size of a variable length array is computed and returned from a
{
char b[n+3]; // variable length array
return sizeof b; // execution time sizeof
- }</pre>
+ }
+</pre>
size_t size;
size = fsize3(10); // fsize3 returns 13
return 0;
- }</pre>
+ }
+</pre>
<p><b> Forward references</b>: common definitions <a href="#7.17"><stddef.h></a> (<a href="#7.17">7.17</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="#6.7.6">6.7.6</a>), array declarators (<a href="#6.7.5.2">6.7.5.2</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 qualified or
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>
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
the same.
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.
<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="#6.7.8">6.7.8</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="note100" href="#note100">100)</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 shall declare at least a declarator (other than the parameters of a function or
extern
static
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
_Complex
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 structure or union shall not contain a member with incomplete or function type (hence,
<p><!--para 17 -->
EXAMPLE 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 18 -->
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.
<p><!--para 19 -->
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 20 -->
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:
<p><!--para 21 -->
<pre>
struct { int n; double d[8]; } *s1;
- struct { int n; double d[5]; } *s2;</pre>
+ struct { int n; double d[5]; } *s2;
+</pre>
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:
<p><!--para 22 -->
<pre>
dp = &(s1->d[0]); // valid
*dp = 42; // valid
dp = &(s2->d[0]); // valid
- *dp = 42; // undefined behavior</pre>
+ *dp = 42; // undefined behavior
+</pre>
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 -->
<p><!--para 6 -->
A type specifier of the form
<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 { enumerator-list }</pre>
+ enum identifier { enumerator-list }
+</pre>
or
<pre>
- enum identifier { enumerator-list , }</pre>
+ enum identifier { enumerator-list , }
+</pre>
declares a structure, union, or enumerated type. The list defines the structure content,
<!--page 119 -->
<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="#note113"><b>113)</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.113)
<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
<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.
type-qualifier:
const
restrict
- volatile</pre>
+ volatile
+</pre>
<h6>Constraints</h6>
<p><!--para 2 -->
Types other than pointer types derived from object or incomplete types shall not be
<p><!--para 10 -->
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.
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>
<h6>footnotes</h6>
<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>
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
example, this permits new_vector to return a vector.
t.n = n;
t.v = malloc(n * sizeof (float));
return t;
- }</pre>
+ }
+</pre>
<h6>footnotes</h6>
<p><!--para 1 -->
<pre>
function-specifier:
- inline</pre>
+ inline
+</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>
- Note that the definition of fahr is an external definition because fahr is also declared with extern, but
+ }
+</pre>
+ 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
external definition has to appear in another translation unit (see <a href="#6.9">6.9</a>); the inline definition and the external
definition are distinct and either may be used for the call.
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.
-<h6> Implementation limits</h6>
+<h6>Implementation limits</h6>
<p><!--para 7 -->
As discussed in <a href="#5.2.4.1">5.2.4.1</a>, an implementation may limit the number of pointer, array, and
function declarators that modify an arithmetic, structure, union, or incomplete type, either
<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 128 -->
<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="#note123"><b>123)</b></a></sup>
(See <a href="#6.7.5.3">6.7.5.3</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="#6.7.5.3">6.7.5.3</a>), function definitions (<a href="#6.9.1">6.9.1</a>),
initialization (<a href="#6.7.8">6.7.8</a>).
<p><!--para 5 -->
If, in the declaration ''T D1'', D1 has the form
<pre>
- D( parameter-type-list )</pre>
+ D( parameter-type-list )
+</pre>
or
<!--page 131 -->
<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 136 -->
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="6.7.8" href="#6.7.8">6.7.8 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 138 -->
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>
+ };
+</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].
<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
structures: w[0].a[0] is 1 and w[1].a[0] is 2; all the other elements are zero.
{ 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 142 -->
<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>
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="#7.17"><stddef.h></a> (<a href="#7.17">7.17</a>).
<!--page 143 -->
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
a default label, control jumps to the labeled statement. If no converted case constant
expression matches and there is no default label, no part of the switch body is
executed.
-<h6> Implementation limits</h6>
+<h6>Implementation limits</h6>
<p><!--para 6 -->
As discussed in <a href="#5.2.4.1">5.2.4.1</a>, the implementation may limit the number of case values in a
switch statement.
/* 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>
<h6>Semantics</h6>
<p><!--para 2 -->
A jump statement causes an unconditional jump to another place.
}
// handle other operations
/* ... */
- }</pre>
+ }
+</pre>
<!--page 150 -->
</ol>
<p><!--para 4 -->
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>
continue; continue; continue;
/* ... */ /* ... */ /* ... */
contin: ; contin: ; contin: ;
- } } while (/* ... */); }</pre>
+ } } while (/* ... */); }
+</pre>
unless the continue statement shown is in an enclosed iteration statement (in which
case it is interpreted within that statement), it is equivalent to goto contin;.<sup><a href="#note138"><b>138)</b></a></sup>
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="note142" href="#note142">142)</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 157 -->
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.
<!--page 160 -->
<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
predefined or if it has been the subject of a #define preprocessing directive without an
intervening #undef directive with the same subject identifier), 0 if it is not.
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
<!--page 161 -->
<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.
evaluate to the same value in these two contexts.
<pre>
#if 'z' - 'a' == 25
- if ('z' - 'a' == 25)</pre>
+ if ('z' - 'a' == 25)
+</pre>
</small>
<p><small><a name="note147" href="#note147">147)</a> As indicated by the syntax, a preprocessing token shall not follow a #else or #endif directive
<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
<!--page 162 -->
<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="#7.19"><stdio.h></a>
- #include "myprog.h"</pre>
+ #include "myprog.h"
+</pre>
<p><!--para 8 -->
EXAMPLE 2 This illustrates macro-replaced #include directives:
#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="#note149"><b>149)</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 168 -->
<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 169 -->
<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-sequence<sub>opt</sub>" new-line</pre>
+ # line digit-sequence "s-char-sequence<sub>opt</sub>" 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="#note152"><b>152)</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>
<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:
<!--page 174 -->
<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 175 -->
<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="#7.4"><ctype.h></a> <a href="#7.10"><limits.h></a> <a href="#7.16"><stdbool.h></a> <a href="#7.22"><tgmath.h></a>
<a href="#7.5"><errno.h></a> <a href="#7.11"><locale.h></a> <a href="#7.17"><stddef.h></a> <a href="#7.23"><time.h></a>
<a href="#7.6"><fenv.h></a> <a href="#7.12"><math.h></a> <a href="#7.18"><stdint.h></a> <a href="#7.24"><wchar.h></a>
- <a href="#7.7"><float.h></a> <a href="#7.13"><setjmp.h></a> <a href="#7.19"><stdio.h></a> <a href="#7.25"><wctype.h></a></pre>
+ <a href="#7.7"><float.h></a> <a href="#7.13"><setjmp.h></a> <a href="#7.19"><stdio.h></a> <a href="#7.25"><wctype.h></a>
+</pre>
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
searched for included source files, the behavior is undefined.
#include <a href="#7.20"><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)
<pre>
#include <a href="#7.20"><stdlib.h></a>
#undef atoi
const char *str;
/* ... */
- i = atoi(str);</pre>
+ i = atoi(str);
+</pre>
or
<pre>
#include <a href="#7.20"><stdlib.h></a>
const char *str;
/* ... */
- i = (atoi)(str);</pre>
+ i = (atoi)(str);
+</pre>
<li> by explicit declaration
<!--page 181 -->
<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.
<p><!--para 1 -->
The header <a href="#7.2"><assert.h></a> defines the assert macro 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 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 2 -->
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="#note167"><b>167)</b></a></sup>
<p><!--para 3 -->
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="#note168"><b>168)</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 4 -->
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 5 -->
<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
#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="#note170"><b>170)</b></a></sup>
#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="#note171"><b>171)</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="#note175"><b>175)</b></a></sup> that has type int, the value of which is set to a
positive error number by several library functions. It is unspecified whether errno is a
macro or an identifier declared with external linkage. If a macro definition is suppressed
<p><!--para 3 -->
The type
<pre>
- fenv_t</pre>
+ fenv_t
+</pre>
represents the entire floating-point environment.
<p><!--para 4 -->
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="#note181"><b>181)</b></a></sup> Additional implementation-defined floating-point
exceptions, with macro definitions beginning with FE_ and an uppercase letter, may also
<p><!--para 6 -->
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 7 -->
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 201 -->
<pre>
- FE_DFL_ENV</pre>
+ FE_DFL_ENV
+</pre>
represents the default floating-point environment -- the one installed at program startup
-- and has type ''pointer to const-qualified fenv_t''. It can be used as an argument to
<a href="#7.6"><fenv.h></a> functions that manage the floating-point environment.
<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>
If the function g might depend on status flags set as a side effect of the first x + 1, or if the second
x + 1 might depend on control modes set as a side effect of the call to function g, then the program shall
contain an appropriately placed invocation of #pragma STDC FENV_ACCESS ON.<sup><a href="#note185"><b>185)</b></a></sup>
<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="#7.18"><stdint.h></a>, it defines corresponding macros for conversion
specifiers for use with the formatted input/output functions.<sup><a href="#note190"><b>190)</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>
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>
The fscanf macros for signed integers are:
<p><!--para 5 -->
<pre>
SCNdN SCNdLEASTN SCNdFASTN SCNdMAX SCNdPTR
- SCNiN SCNiLEASTN SCNiFASTN SCNiMAX SCNiPTR</pre>
+ SCNiN SCNiLEASTN SCNiFASTN SCNiMAX SCNiPTR
+</pre>
The fscanf macros for unsigned integers are:
<p><!--para 6 -->
<pre>
SCNoN SCNoLEASTN SCNoFASTN SCNoMAX SCNoPTR
SCNuN SCNuLEASTN SCNuFASTN SCNuMAX SCNuPTR
- SCNxN SCNxLEASTN SCNxFASTN SCNxMAX SCNxPTR</pre>
+ SCNxN SCNxLEASTN SCNxFASTN SCNxMAX SCNxPTR
+</pre>
For each type that the implementation provides in <a href="#7.18"><stdint.h></a>, the corresponding
fprintf macros shall be defined and the corresponding fscanf macros shall be
defined unless the implementation does not have a suitable fscanf length modifier for
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>
The macros defined are NULL (described in <a href="#7.17">7.17</a>); and
<pre>
LC_ALL
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="#note194"><b>194)</b></a></sup> Additional macro definitions, beginning
with the characters LC_ and an uppercase letter,<sup><a href="#note195"><b>195)</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 -->
The implementation shall behave as if no library function calls the setlocale function.
<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
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>
<!--page 224 -->
<h3><a name="7.12" href="#7.12">7.12 Mathematics <math.h></a></h3>
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="#note200"><b>200)</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="#note202"><b>202)</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,
#define fpclassify(x) \
((sizeof (x) == sizeof (float)) ? __fpclassifyf(x) : \
(sizeof (x) == sizeof (double)) ? __fpclassifyd(x) : \
- __fpclassifyl(x))</pre>
+ __fpclassifyl(x))
+</pre>
<h6>footnotes</h6>
<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>
<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="#note207"><b>207)</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="#note209"><b>209)</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 FLT_RADIX<sup>-logb(x)</sup> < FLT_RADIX</pre>
+ 1 <= x FLT_RADIX<sup>-logb(x)</sup> < FLT_RADIX
+</pre>
A domain error or range 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 FLT_RADIX<sup>n</sup> 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,
#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
#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
erf x = --- (integral) e<sup>-t<sup>2</sup></sup> dt .
- (sqrt)(pi) 0 </pre>
+ (sqrt)(pi) 0
+</pre>
<h5><a name="7.12.8.2" href="#7.12.8.2">7.12.8.2 The erfc functions</a></h5>
<h6>Synopsis</h6>
#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)
erfc x = 1 - erf x = --- (integral) e<sup>-t<sup>2</sup></sup> dt .
- (sqrt)(pi) x </pre>
+ (sqrt)(pi) x
+</pre>
<!--page 243 -->
<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 range 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="#note210"><b>210)</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="#note214"><b>214)</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 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>
<h6>Description</h6>
<p><!--para 2 -->
The isgreaterequal macro determines whether its first argument is greater than or
<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
If the return is from a direct invocation, the setjmp macro returns the value zero. If the
return is from a call to the longjmp function, the setjmp macro returns a nonzero
value.
-<h6> Environmental limits</h6>
+<h6>Environmental limits</h6>
<p><!--para 4 -->
An invocation of the setjmp macro shall appear only in one of the following contexts:
<ul>
<p><!--para 1 -->
<pre>
#include <a href="#7.13"><setjmp.h></a>
- void longjmp(jmp_buf env, int val);</pre>
+ 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="note217" href="#note217">217)</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>
An implementation need not generate any of these signals, except as a result of explicit
calls to the raise function. Additional signals and pointers to undeclarable functions,
with macro definitions beginning, respectively, with the letters SIG and an uppercase
<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>
<!--page 260 -->
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 3 -->
The type declared is
<pre>
- va_list</pre>
+ va_list
+</pre>
which is an 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="#7.15"><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="#7.15"><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="#7.15"><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="#7.15"><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="7.16" href="#7.16">7.16 Boolean type and values <stdbool.h></a></h3>
<p><!--para 1 -->
<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; 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>
+<h6>Recommended practice</h6>
<p><!--para 4 -->
The types used for size_t and ptrdiff_t should not have an integer conversion rank
greater than that of signed long int unless the implementation supports objects
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="7.18.1.3" href="#7.18.1.3">7.18.1.3 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="7.18.1.5" href="#7.18.1.5">7.18.1.5 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="7.18.2" href="#7.18.2">7.18.2 Limits of specified-width integer types</a></h4>
<ul>
<li> minimum values of exact-width signed integer types
<pre>
- INTN_MIN exactly -(2<sup>N-1</sup>)</pre>
+ INTN_MIN exactly -(2<sup>N-1</sup>)
+</pre>
<li> maximum values of exact-width signed integer types
<pre>
- INTN_MAX exactly 2<sup>N-1</sup> - 1</pre>
+ INTN_MAX exactly 2<sup>N-1</sup> - 1
+</pre>
<li> maximum values of exact-width unsigned integer types
<pre>
- UINTN_MAX exactly 2<sup>N</sup> - 1</pre>
+ UINTN_MAX exactly 2<sup>N</sup> - 1
+</pre>
</ul>
<h5><a name="7.18.2.2" href="#7.18.2.2">7.18.2.2 Limits of minimum-width integer types</a></h5>
<ul>
<li> minimum values of minimum-width signed integer types
<pre>
- INT_LEASTN_MIN -(2<sup>N-1</sup> - 1)</pre>
+ INT_LEASTN_MIN -(2<sup>N-1</sup> - 1)
+</pre>
<li> maximum values of minimum-width signed integer types
<pre>
- INT_LEASTN_MAX 2<sup>N-1</sup> - 1</pre>
+ INT_LEASTN_MAX 2<sup>N-1</sup> - 1
+</pre>
<li> maximum values of minimum-width unsigned integer types
<pre>
- UINT_LEASTN_MAX 2<sup>N</sup> - 1</pre>
+ UINT_LEASTN_MAX 2<sup>N</sup> - 1
+</pre>
</ul>
<h5><a name="7.18.2.3" href="#7.18.2.3">7.18.2.3 Limits of fastest minimum-width integer types</a></h5>
<ul>
<li> minimum values of fastest minimum-width signed integer types
<pre>
- INT_FASTN_MIN -(2<sup>N-1</sup> - 1)</pre>
+ INT_FASTN_MIN -(2<sup>N-1</sup> - 1)
+</pre>
<li> maximum values of fastest minimum-width signed integer types
<pre>
- INT_FASTN_MAX 2<sup>N-1</sup> - 1</pre>
+ INT_FASTN_MAX 2<sup>N-1</sup> - 1
+</pre>
<li> maximum values of fastest minimum-width unsigned integer types
<pre>
- UINT_FASTN_MAX 2<sup>N</sup> - 1</pre>
+ UINT_FASTN_MAX 2<sup>N</sup> - 1
+</pre>
</ul>
<h5><a name="7.18.2.4" href="#7.18.2.4">7.18.2.4 Limits of integer types capable of holding object pointers</a></h5>
<ul>
<li> minimum value of pointer-holding signed integer type
<pre>
- INTPTR_MIN -(2<sup>15</sup> - 1)</pre>
+ INTPTR_MIN -(2<sup>15</sup> - 1)
+</pre>
<li> maximum value of pointer-holding signed integer type
<!--page 271 -->
<pre>
- INTPTR_MAX 2<sup>15</sup> - 1</pre>
+ INTPTR_MAX 2<sup>15</sup> - 1
+</pre>
<li> maximum value of pointer-holding unsigned integer type
<pre>
- UINTPTR_MAX 2<sup>16</sup> - 1</pre>
+ UINTPTR_MAX 2<sup>16</sup> - 1
+</pre>
</ul>
<h5><a name="7.18.2.5" href="#7.18.2.5">7.18.2.5 Limits of greatest-width integer types</a></h5>
<ul>
<li> minimum value of greatest-width signed integer type
<pre>
- INTMAX_MIN -(2<sup>63</sup> - 1)</pre>
+ INTMAX_MIN -(2<sup>63</sup> - 1)
+</pre>
<li> maximum value of greatest-width signed integer type
<pre>
- INTMAX_MAX 2<sup>63</sup> - 1</pre>
+ INTMAX_MAX 2<sup>63</sup> - 1
+</pre>
<li> maximum value of greatest-width unsigned integer type
<pre>
- UINTMAX_MAX 2<sup>64</sup> - 1</pre>
+ UINTMAX_MAX 2<sup>64</sup> - 1
+</pre>
</ul>
<h4><a name="7.18.3" href="#7.18.3">7.18.3 Limits of other integer types</a></h4>
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 274 -->
<pre>
- UINTMAX_C(value)</pre>
+ UINTMAX_C(value)
+</pre>
<h3><a name="7.19" href="#7.19">7.19 Input/output <stdio.h></a></h3>
<p><!--para 2 -->
The types declared are size_t (described in <a href="#7.17">7.17</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 an 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 275 -->
guarantees can be opened;<sup><a href="#note231"><b>231)</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 maximum 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 -->
value of this mbstate_t object as part of the value of the fpos_t object. A later
successful call to fsetpos using the same stored fpos_t value restores the value of
the associated mbstate_t object as well as the position within the controlled stream.
-<h6> Environmental limits</h6>
+<h6>Environmental limits</h6>
<p><!--para 7 -->
An implementation shall support text files with lines containing at least 254 characters,
including the terminating new-line character. The value of the macro BUFSIZ shall be at
multibyte character. The wide character input/output functions and the byte input/output
functions store the value of the macro EILSEQ in errno if and only if an encoding error
occurs.
-<h6> Environmental limits</h6>
+<h6>Environmental limits</h6>
<p><!--para 15 -->
The value of FOPEN_MAX shall be at least eight, including the three standard text
streams.
<p><!--para 1 -->
<pre>
#include <a href="#7.19"><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="#7.19"><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="#7.19"><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
existing file and that will automatically be removed when it is closed or at program
termination. If the program terminates abnormally, whether an open temporary file is
removed is implementation-defined. The file is opened for update with "wb+" mode.
-<h6> Recommended practice</h6>
+<h6>Recommended practice</h6>
<p><!--para 3 -->
It should be possible to open at least TMP_MAX temporary files during the lifetime of the
program (this limit may be shared with tmpnam) and there should be no limit on the
<p><!--para 1 -->
<pre>
#include <a href="#7.19"><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
function may modify the same object). If the argument is not a null pointer, it is assumed
to point to an array of at least L_tmpnam chars; the tmpnam function writes its result
in that array and returns the argument as its value.
-<h6> Environmental limits</h6>
+<h6>Environmental limits</h6>
<p><!--para 6 -->
The value of the macro TMP_MAX shall be at least 25.
<p><!--para 1 -->
<pre>
#include <a href="#7.19"><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
<!--page 283 -->
<pre>
#include <a href="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><stdio.h></a>
int setvbuf(FILE * restrict stream,
char * restrict buf,
- int mode, size_t size);</pre>
+ int mode, size_t size);
+</pre>
<pre>
#include <a href="#7.19"><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
<p><!--para 11 -->
For a and A conversions, if FLT_RADIX is a power of 2, the value is correctly rounded
to a hexadecimal floating number with the given precision.
-<h6> Recommended practice</h6>
+<h6>Recommended practice</h6>
<p><!--para 12 -->
For a and A conversions, if FLT_RADIX is not a power of 2 and the result is not exactly
representable in the given precision, the result should be one of the two adjacent numbers
<p><!--para 14 -->
The fprintf function returns the number of characters transmitted, or a negative value
if an output or encoding error occurred.
-<h6> Environmental limits</h6>
+<h6>Environmental limits</h6>
<p><!--para 15 -->
The number of characters that can be produced by any single conversion shall be at least
4095.
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="#7.24.6">7.24.6</a>), the wcrtomb function (<a href="#7.24.6.3.3">7.24.6.3.3</a>).
<pre>
#include <a href="#7.19"><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
#include <a href="#7.19"><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="#7.19"><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:
<!--page 300 -->
<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>
If the stdin stream contains the following lines:
<pre>
2 quarts of oil
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="#7.19"><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="#7.19"><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="#7.17"><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="#7.17"><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="#7.17"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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>
#include <a href="#7.19"><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="#7.15"><stdarg.h></a>
#include <a href="#7.19"><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="#7.15"><stdarg.h></a>
#include <a href="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><stdio.h></a>
- char *gets(char *s);</pre>
+ char *gets(char *s);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The gets function reads characters from the input stream pointed to by stdin, into the
<p><!--para 1 -->
<pre>
#include <a href="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.19"><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="#7.17">7.17</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="#7.17">7.17</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="#7.20"><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="#7.20"><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
If the subject sequence is empty or does not have the expected form, no conversion is
performed; the value of nptr is stored in the object pointed to by endptr, provided
that endptr is not a null pointer.
-<h6> Recommended practice</h6>
+<h6>Recommended practice</h6>
<p><!--para 8 -->
If the subject sequence has the hexadecimal form, FLT_RADIX is not a power of 2, and
the result is not exactly representable, the result should be one of the two numbers in the
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="#7.20"><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
<h6>Returns</h6>
<p><!--para 4 -->
The rand function returns a pseudo-random integer.
-<h6> Environmental limits</h6>
+<h6>Environmental limits</h6>
<p><!--para 5 -->
The value of the RAND_MAX macro shall be at least 32767.
<p><!--para 1 -->
<pre>
#include <a href="#7.20"><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="7.20.3" href="#7.20.3">7.20.3 Memory management functions</a></h4>
<p><!--para 1 -->
<pre>
#include <a href="#7.20"><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="#7.20"><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="#7.20"><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="#7.20"><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="#7.20"><stdlib.h></a>
- void abort(void);</pre>
+ 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="#7.20"><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
arguments at normal program termination.
-<h6> Environmental limits</h6>
+<h6>Environmental limits</h6>
<p><!--para 3 -->
The implementation shall support the registration of at least 32 functions.
<h6>Returns</h6>
<p><!--para 1 -->
<pre>
#include <a href="#7.20"><stdlib.h></a>
- void exit(int status);</pre>
+ void exit(int status);
+</pre>
<h6>Description</h6>
<p><!--para 2 -->
The exit function causes normal program termination to occur. If more than one call to
<p><!--para 1 -->
<pre>
#include <a href="#7.20"><stdlib.h></a>
- void _Exit(int status);</pre>
+ 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="#7.20"><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="#7.20"><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>
<h5><a name="7.20.5.1" href="#7.20.5.1">7.20.5.1 The bsearch function</a></h5>
#include <a href="#7.20"><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="#7.20"><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="#7.20"><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="#7.20"><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="#7.20"><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
mbtowc function is not affected, it is equivalent to
<p><!--para 3 -->
<pre>
- mbtowc((wchar_t *)0, s, n);</pre>
+ mbtowc((wchar_t *)0, s, n);
+</pre>
The implementation shall behave as if no library function calls the mblen function.
<h6>Returns</h6>
<p><!--para 4 -->
#include <a href="#7.20"><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="#7.20"><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="#7.20"><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="#7.20"><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="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="7.21.5" href="#7.21.5">7.21.5 Search functions</a></h4>
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="#7.21"><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="7.21.6" href="#7.21.6">7.21.6 Miscellaneous functions</a></h4>
<p><!--para 1 -->
<pre>
#include <a href="#7.21"><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="#7.21"><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="#7.21"><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.
<p><!--para 6 -->
<!--page 349 -->
<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 350 -->
<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="note272" href="#note272">272)</a> Like other function-like macros in Standard libraries, each type-generic macro can be suppressed to
<p><!--para 2 -->
The macros defined are NULL (described in <a href="#7.17">7.17</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="#7.17">7.17</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="#7.23"><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="#7.23"><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="#7.23"><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="#7.23"><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="#7.23"><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 354 -->
<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.
<pre>
char *asctime(const struct tm *timeptr)
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><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>
<h6>Returns</h6>
<p><!--para 3 -->
The ctime function returns the pointer returned by the asctime function with that
<p><!--para 1 -->
<pre>
#include <a href="#7.23"><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="#7.23"><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
<p><!--para 2 -->
The types declared are wchar_t and size_t (both described in <a href="#7.17">7.17</a>);
<pre>
- mbstate_t</pre>
+ mbstate_t
+</pre>
which is an 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="#note278"><b>278)</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="#7.23.1">7.23.1</a>).
<p><!--para 3 -->
The macros defined are NULL (described in <a href="#7.17">7.17</a>); WCHAR_MIN and WCHAR_MAX
(described in <a href="#7.18.3">7.18.3</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="#note279"><b>279)</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="#7.19"><stdio.h></a>
#include <a href="#7.24"><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
<p><!--para 11 -->
For a and A conversions, if FLT_RADIX is a power of 2, the value is correctly rounded
to a hexadecimal floating number with the given precision.
-<h6> Recommended practice</h6>
+<h6>Recommended practice</h6>
<p><!--para 12 -->
For a and A conversions, if FLT_RADIX is not a power of 2 and the result is not exactly
representable in the given precision, the result should be one of the two adjacent numbers
value if an output or encoding error occurred.
<!--page 368 -->
-<h6> Environmental limits</h6>
+<h6>Environmental limits</h6>
<p><!--para 15 -->
The number of wide characters that can be produced by any single conversion shall be at
least 4095.
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="#7.24.6.1.1">7.24.6.1.1</a>), the mbrtowc function
(<a href="#7.24.6.3.2">7.24.6.3.2</a>).
#include <a href="#7.19"><stdio.h></a>
#include <a href="#7.24"><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
#include <a href="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.15"><stdarg.h></a>
#include <a href="#7.24"><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="#7.15"><stdarg.h></a>
#include <a href="#7.24"><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="#7.24"><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="#7.24"><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="#7.19"><stdio.h></a>
#include <a href="#7.24"><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="#7.19"><stdio.h></a>
#include <a href="#7.24"><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="#7.19"><stdio.h></a>
#include <a href="#7.24"><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="#7.19"><stdio.h></a>
#include <a href="#7.24"><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="#7.19"><stdio.h></a>
#include <a href="#7.24"><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="#7.19"><stdio.h></a>
#include <a href="#7.24"><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="#7.24"><wchar.h></a>
- wint_t getwchar(void);</pre>
+ wint_t getwchar(void);
+</pre>
<pre>
#include <a href="#7.19"><stdio.h></a>
#include <a href="#7.24"><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="#7.24"><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="#7.19"><stdio.h></a>
#include <a href="#7.24"><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.
If the subject sequence is empty or does not have the expected form, no conversion is
performed; the value of nptr is stored in the object pointed to by endptr, provided
that endptr is not a null pointer.
-<h6> Recommended practice</h6>
+<h6>Recommended practice</h6>
<p><!--para 8 -->
If the subject sequence has the hexadecimal form, FLT_RADIX is not a power of 2, and
the result is not exactly representable, the result should be one of the two numbers in the
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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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 393 -->
<pre>
- 1 + wcsxfrm(NULL, s, 0)</pre>
+ 1 + wcsxfrm(NULL, s, 0)
+</pre>
<h5><a name="7.24.4.4.5" href="#7.24.4.4.5">7.24.4.4.5 The wmemcmp function</a></h5>
<pre>
#include <a href="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="#7.24"><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="7.24.4.5.8" href="#7.24.4.5.8">7.24.4.5.8 The wmemchr function</a></h5>
<pre>
#include <a href="#7.24"><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="#7.24"><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="#7.24"><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:
<pre>
#include <a href="#7.19"><stdio.h></a>
#include <a href="#7.24"><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
<pre>
#include <a href="#7.19"><stdio.h></a>
#include <a href="#7.24"><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="#7.24"><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 pointed-to
#include <a href="#7.24"><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
#include <a href="#7.24"><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="#7.24.1">7.24.1</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="#7.25"><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="#7.25"><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="#7.25"><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="#7.25"><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="#7.25"><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="#7.25"><wctype.h></a>
- int iswgraph(wint_t wc);</pre>
+ int iswgraph(wint_t wc);
+</pre>
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><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="#7.25"><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="#7.25"><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="#7.25"><wctype.h></a>
- int iswspace(wint_t wc);</pre>
+ int iswspace(wint_t wc);
+</pre>
<p><!--para 1 -->
<pre>
#include <a href="#7.25"><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="#7.25"><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="#7.25"><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="#7.25"><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="#7.25"><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="#7.25"><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="#7.25"><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="#7.25.3.1">7.25.3.1</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="#7.25"><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.
<p><!--para 1 -->
<pre>
(informative)
- Language syntax summary</pre>
+ Language syntax summary
+</pre>
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:
<pre>
header-name
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
default inline struct _Imaginary
do int switch
double long typedef
- else register union</pre>
+ else register union
+</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
<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-suffixopt
octal-constant integer-suffixopt
- hexadecimal-constant integer-suffixopt</pre>
+ hexadecimal-constant integer-suffixopt
+</pre>
(<a href="#6.4.4.1">6.4.4.1</a>) decimal-constant:
<!--page 417 -->
<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
<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-suffixopt
unsigned-suffix long-long-suffix
long-suffix unsigned-suffixopt
- long-long-suffix unsigned-suffixopt</pre>
+ long-long-suffix unsigned-suffixopt
+</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:
<!--page 418 -->
<pre>
fractional-constant exponent-partopt floating-suffixopt
- digit-sequence exponent-part floating-suffixopt</pre>
+ digit-sequence exponent-part floating-suffixopt
+</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-suffixopt
hexadecimal-prefix hexadecimal-digit-sequence
- binary-exponent-part floating-suffixopt</pre>
+ binary-exponent-part floating-suffixopt
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) fractional-constant:
<pre>
digit-sequenceopt . digit-sequence
- digit-sequence .</pre>
+ digit-sequence .
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) exponent-part:
<pre>
e signopt digit-sequence
- E signopt digit-sequence</pre>
+ E signopt digit-sequence
+</pre>
(<a href="#6.4.4.2">6.4.4.2</a>) sign: one of
<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-sequenceopt .
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 signopt digit-sequence
- P signopt digit-sequence</pre>
+ P signopt 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:
<!--page 419 -->
<pre>
' c-char-sequence '
- L' c-char-sequence '</pre>
+ L' 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:
<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>
" s-char-sequenceopt "
- L" s-char-sequenceopt "</pre>
+ L" s-char-sequenceopt "
+</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:
<!--page 420 -->
<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>
identifier
constant
string-literal
- ( expression )</pre>
+ ( 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:
<pre>
postfix-expression
-- unary-expression
unary-operator cast-expression
sizeof unary-expression
- sizeof ( type-name )</pre>
+ sizeof ( 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:
<!--page 422 -->
<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:
<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:
<!--page 423 -->
<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-listopt ;</pre>
+ declaration-specifiers init-declarator-listopt ;
+</pre>
(<a href="#6.7">6.7</a>) declaration-specifiers:
<pre>
storage-class-specifier declaration-specifiersopt
type-specifier declaration-specifiersopt
type-qualifier declaration-specifiersopt
- function-specifier declaration-specifiersopt</pre>
+ function-specifier declaration-specifiersopt
+</pre>
(<a href="#6.7">6.7</a>) init-declarator-list:
<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:
<!--page 424 -->
<pre>
extern
static
auto
- register</pre>
+ register
+</pre>
(<a href="#6.7.2">6.7.2</a>) type-specifier:
<pre>
void
_Complex
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 identifieropt { 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:
<pre>
- specifier-qualifier-list struct-declarator-list ;</pre>
+ specifier-qualifier-list struct-declarator-list ;
+</pre>
(<a href="#6.7.2.1">6.7.2.1</a>) specifier-qualifier-list:
<pre>
type-specifier specifier-qualifier-listopt
- type-qualifier specifier-qualifier-listopt</pre>
+ type-qualifier specifier-qualifier-listopt
+</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:
<!--page 425 -->
<pre>
declarator
- declaratoropt : constant-expression</pre>
+ declaratoropt : constant-expression
+</pre>
(<a href="#6.7.2.2">6.7.2.2</a>) enum-specifier:
<pre>
enum identifieropt { enumerator-list }
enum identifieropt { 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="#6.7.3">6.7.3</a>) type-qualifier:
<pre>
const
restrict
- volatile</pre>
+ volatile
+</pre>
(<a href="#6.7.4">6.7.4</a>) function-specifier:
<pre>
- inline</pre>
+ inline
+</pre>
(<a href="#6.7.5">6.7.5</a>) declarator:
<pre>
- pointeropt direct-declarator</pre>
+ pointeropt direct-declarator
+</pre>
(<a href="#6.7.5">6.7.5</a>) direct-declarator:
<pre>
identifier
direct-declarator [ type-qualifier-list static assignment-expression ]
direct-declarator [ type-qualifier-listopt * ]
direct-declarator ( parameter-type-list )
- direct-declarator ( identifier-listopt )</pre>
+ direct-declarator ( identifier-listopt )
+</pre>
(<a href="#6.7.5">6.7.5</a>) pointer:
<pre>
* type-qualifier-listopt
- * type-qualifier-listopt pointer</pre>
+ * type-qualifier-listopt pointer
+</pre>
(<a href="#6.7.5">6.7.5</a>) type-qualifier-list:
<pre>
type-qualifier
- type-qualifier-list type-qualifier</pre>
+ type-qualifier-list type-qualifier
+</pre>
(<a href="#6.7.5">6.7.5</a>) parameter-type-list:
<!--page 426 -->
<pre>
parameter-list
- parameter-list , ...</pre>
+ parameter-list , ...
+</pre>
(<a href="#6.7.5">6.7.5</a>) parameter-list:
<pre>
parameter-declaration
- parameter-list , parameter-declaration</pre>
+ parameter-list , parameter-declaration
+</pre>
(<a href="#6.7.5">6.7.5</a>) parameter-declaration:
<pre>
declaration-specifiers declarator
- declaration-specifiers abstract-declaratoropt</pre>
+ declaration-specifiers abstract-declaratoropt
+</pre>
(<a href="#6.7.5">6.7.5</a>) identifier-list:
<pre>
identifier
- identifier-list , identifier</pre>
+ identifier-list , identifier
+</pre>
(<a href="#6.7.6">6.7.6</a>) type-name:
<pre>
- specifier-qualifier-list abstract-declaratoropt</pre>
+ specifier-qualifier-list abstract-declaratoropt
+</pre>
(<a href="#6.7.6">6.7.6</a>) abstract-declarator:
<pre>
pointer
- pointeropt direct-abstract-declarator</pre>
+ pointeropt direct-abstract-declarator
+</pre>
(<a href="#6.7.6">6.7.6</a>) direct-abstract-declarator:
<pre>
( abstract-declarator )
direct-abstract-declaratoropt [ type-qualifier-list static
assignment-expression ]
direct-abstract-declaratoropt [ * ]
- direct-abstract-declaratoropt ( parameter-type-listopt )</pre>
+ direct-abstract-declaratoropt ( parameter-type-listopt )
+</pre>
(<a href="#6.7.7">6.7.7</a>) typedef-name:
<pre>
- identifier</pre>
+ identifier
+</pre>
(<a href="#6.7.8">6.7.8</a>) initializer:
<pre>
assignment-expression
{ initializer-list }
- { initializer-list , }</pre>
+ { initializer-list , }
+</pre>
(<a href="#6.7.8">6.7.8</a>) initializer-list:
<pre>
designationopt initializer
- initializer-list , designationopt initializer</pre>
+ initializer-list , designationopt initializer
+</pre>
(<a href="#6.7.8">6.7.8</a>) designation:
<!--page 427 -->
<pre>
- designator-list =</pre>
+ designator-list =
+</pre>
(<a href="#6.7.8">6.7.8</a>) designator-list:
<pre>
designator
- designator-list designator</pre>
+ designator-list designator
+</pre>
(<a href="#6.7.8">6.7.8</a>) designator:
<pre>
[ constant-expression ]
- . identifier</pre>
+ . identifier
+</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-listopt }</pre>
+ { block-item-listopt }
+</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>
- expressionopt ;</pre>
+ expressionopt ;
+</pre>
(<a href="#6.8.4">6.8.4</a>) selection-statement:
<!--page 428 -->
<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 ( expressionopt ; expressionopt ; expressionopt ) statement
- for ( declaration expressionopt ; expressionopt ) statement</pre>
+ for ( declaration expressionopt ; expressionopt ) statement
+</pre>
(<a href="#6.8.6">6.8.6</a>) jump-statement:
<pre>
goto identifier ;
continue ;
break ;
- return expressionopt ;</pre>
+ return expressionopt ;
+</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-listopt compound-statement</pre>
+ declaration-specifiers declarator declaration-listopt 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>
- groupopt</pre>
+ groupopt
+</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:
<!--page 429 -->
<pre>
- if-group elif-groupsopt else-groupopt endif-line</pre>
+ if-group elif-groupsopt else-groupopt endif-line
+</pre>
(<a href="#6.10">6.10</a>) if-group:
<pre>
# if constant-expression new-line groupopt
# ifdef identifier new-line groupopt
- # ifndef identifier new-line groupopt</pre>
+ # ifndef identifier new-line groupopt
+</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:
<pre>
- # elif constant-expression new-line groupopt</pre>
+ # elif constant-expression new-line groupopt
+</pre>
(<a href="#6.10">6.10</a>) else-group:
<pre>
- # else new-line groupopt</pre>
+ # else new-line groupopt
+</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-tokensopt new-line
# pragma pp-tokensopt new-line
- # new-line</pre>
+ # new-line
+</pre>
(<a href="#6.10">6.10</a>) text-line:
<pre>
- pp-tokensopt new-line</pre>
+ pp-tokensopt 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:
<!--page 430 -->
<pre>
- pp-tokensopt</pre>
+ pp-tokensopt
+</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 431 -->
<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
- 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 432 -->
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</pre>
+ EDOM EILSEQ ERANGE errno
+</pre>
<h3><a name="B.5" href="#B.5">B.5 Floating-point environment <fenv.h></a></h3>
<!--page 434 -->
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>
FLT_DIG LDBL_MAX_EXP DBL_MIN
DBL_DIG FLT_MAX_10_EXP LDBL_MIN
LDBL_DIG DBL_MAX_10_EXP
- FLT_MIN_EXP LDBL_MAX_10_EXP</pre>
+ FLT_MIN_EXP 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 435 -->
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 436 -->
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);
- void longjmp(jmp_buf env, int val);</pre>
+ void longjmp(jmp_buf env, int val);
+</pre>
<h3><a name="B.13" href="#B.13">B.13 Signal handling <signal.h></a></h3>
<pre>
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 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.15" href="#B.15">B.15 Boolean type and values <stdbool.h></a></h3>
<!--page 441 -->
bool
true
false
- __bool_true_false_are_defined</pre>
+ __bool_true_false_are_defined
+</pre>
<h3><a name="B.16" href="#B.16">B.16 Common definitions <stddef.h></a></h3>
<pre>
ptrdiff_t size_t wchar_t NULL
- offsetof(type, member-designator)</pre>
+ offsetof(type, member-designator)
+</pre>
<h3><a name="B.17" href="#B.17">B.17 Integer types <stdint.h></a></h3>
<pre>
uintmax_t INTMAX_MIN UINTN_C(value)
INTN_MIN INTMAX_MAX INTMAX_C(value)
INTN_MAX UINTMAX_MAX UINTMAX_C(value)
- UINTN_MAX PTRDIFF_MIN</pre>
+ UINTN_MAX PTRDIFF_MIN
+</pre>
<h3><a name="B.18" href="#B.18">B.18 Input/output <stdio.h></a></h3>
<!--page 442 -->
void clearerr(FILE *stream);
int feof(FILE *stream);
int ferror(FILE *stream);
- void perror(const char *s);</pre>
+ void perror(const char *s);
+</pre>
<h3><a name="B.19" href="#B.19">B.19 General utilities <stdlib.h></a></h3>
<!--page 444 -->
size_t mbstowcs(wchar_t * restrict pwcs,
const char * restrict s, size_t n);
size_t wcstombs(char * restrict s,
- const wchar_t * restrict pwcs, size_t n);</pre>
+ const wchar_t * restrict pwcs, size_t n);
+</pre>
<h3><a name="B.20" href="#B.20">B.20 String handling <string.h></a></h3>
<!--page 446 -->
const char * restrict s2);
void *memset(void *s, int c, size_t n);
char *strerror(int errnum);
- size_t strlen(const char *s);</pre>
+ size_t strlen(const char *s);
+</pre>
<h3><a name="B.21" href="#B.21">B.21 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.22" href="#B.22">B.22 Date and time <time.h></a></h3>
<!--page 447 -->
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>
<h3><a name="B.23" href="#B.23">B.23 Extended multibyte/wide character utilities <wchar.h></a></h3>
<!--page 448 -->
mbstate_t * restrict ps);
size_t wcsrtombs(char * restrict dst,
const wchar_t ** restrict src, size_t len,
- mbstate_t * restrict ps);</pre>
+ mbstate_t * restrict ps);
+</pre>
<h3><a name="B.24" href="#B.24">B.24 Wide character classification and mapping utilities <wctype.h></a></h3>
<!--page 450 -->
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>
<p><!--para 1 -->
<pre>
(informative)
- Sequence points</pre>
+ Sequence points
+</pre>
The following are the sequence points described in <a href="#5.1.2.3">5.1.2.3</a>:
<ul>
<li> The call to a function, after the arguments have been evaluated (<a href="#6.5.2.2">6.5.2.2</a>).
<p><!--para 1 -->
<pre>
(normative)
- Universal character names for identifiers</pre>
+ Universal character names for identifiers
+</pre>
This clause lists the hexadecimal code values that are valid in universal character names
in identifiers.
<p><!--para 2 -->
sets.
Latin: 00AA, 00BA, 00C0-00D6, 00D8-00F6, 00F8-01F5, 01FA-0217,
<pre>
- 0250-02A8, 1E00-1E9B, 1EA0-1EF9, 207F</pre>
+ 0250-02A8, 1E00-1E9B, 1EA0-1EF9, 207F
+</pre>
Greek: 0386, 0388-038A, 038C, 038E-03A1, 03A3-03CE, 03D0-03D6,
<pre>
03DA, 03DC, 03DE, 03E0, 03E2-03F3, 1F00-1F15, 1F18-1F1D,
1F20-1F45, 1F48-1F4D, 1F50-1F57, 1F59, 1F5B, 1F5D,
1F5F-1F7D, 1F80-1FB4, 1FB6-1FBC, 1FC2-1FC4, 1FC6-1FCC,
- 1FD0-1FD3, 1FD6-1FDB, 1FE0-1FEC, 1FF2-1FF4, 1FF6-1FFC</pre>
+ 1FD0-1FD3, 1FD6-1FDB, 1FE0-1FEC, 1FF2-1FF4, 1FF6-1FFC
+</pre>
Cyrillic: 0401-040C, 040E-044F, 0451-045C, 045E-0481, 0490-04C4,
<pre>
- 04C7-04C8, 04CB-04CC, 04D0-04EB, 04EE-04F5, 04F8-04F9</pre>
+ 04C7-04C8, 04CB-04CC, 04D0-04EB, 04EE-04F5, 04F8-04F9
+</pre>
Armenian: 0531-0556, 0561-0587
Hebrew: 05B0-05B9, 05BB-05BD, 05BF, 05C1-05C2, 05D0-05EA,
<pre>
- 05F0-05F2</pre>
+ 05F0-05F2
+</pre>
Arabic: 0621-063A, 0640-0652, 0670-06B7, 06BA-06BE, 06C0-06CE,
<pre>
- 06D0-06DC, 06E5-06E8, 06EA-06ED</pre>
+ 06D0-06DC, 06E5-06E8, 06EA-06ED
+</pre>
Devanagari: 0901-0903, 0905-0939, 093E-094D, 0950-0952, 0958-0963
Bengali: 0981-0983, 0985-098C, 098F-0990, 0993-09A8, 09AA-09B0,
<pre>
09B2, 09B6-09B9, 09BE-09C4, 09C7-09C8, 09CB-09CD,
- 09DC-09DD, 09DF-09E3, 09F0-09F1</pre>
+ 09DC-09DD, 09DF-09E3, 09F0-09F1
+</pre>
Gurmukhi: 0A02, 0A05-0A0A, 0A0F-0A10, 0A13-0A28, 0A2A-0A30,
<pre>
0A32-0A33, 0A35-0A36, 0A38-0A39, 0A3E-0A42, 0A47-0A48,
- 0A4B-0A4D, 0A59-0A5C, 0A5E, 0A74</pre>
+ 0A4B-0A4D, 0A59-0A5C, 0A5E, 0A74
+</pre>
Gujarati: 0A81-0A83, 0A85-0A8B, 0A8D, 0A8F-0A91, 0A93-0AA8,
<pre>
0AAA-0AB0, 0AB2-0AB3, 0AB5-0AB9, 0ABD-0AC5,
- 0AC7-0AC9, 0ACB-0ACD, 0AD0, 0AE0</pre>
+ 0AC7-0AC9, 0ACB-0ACD, 0AD0, 0AE0
+</pre>
Oriya: 0B01-0B03, 0B05-0B0C, 0B0F-0B10, 0B13-0B28, 0B2A-0B30,
<!--page 453 -->
<pre>
0B32-0B33, 0B36-0B39, 0B3E-0B43, 0B47-0B48, 0B4B-0B4D,
- 0B5C-0B5D, 0B5F-0B61</pre>
+ 0B5C-0B5D, 0B5F-0B61
+</pre>
Tamil: 0B82-0B83, 0B85-0B8A, 0B8E-0B90, 0B92-0B95, 0B99-0B9A,
<pre>
0B9C, 0B9E-0B9F, 0BA3-0BA4, 0BA8-0BAA, 0BAE-0BB5,
- 0BB7-0BB9, 0BBE-0BC2, 0BC6-0BC8, 0BCA-0BCD</pre>
+ 0BB7-0BB9, 0BBE-0BC2, 0BC6-0BC8, 0BCA-0BCD
+</pre>
Telugu: 0C01-0C03, 0C05-0C0C, 0C0E-0C10, 0C12-0C28, 0C2A-0C33,
<pre>
- 0C35-0C39, 0C3E-0C44, 0C46-0C48, 0C4A-0C4D, 0C60-0C61</pre>
+ 0C35-0C39, 0C3E-0C44, 0C46-0C48, 0C4A-0C4D, 0C60-0C61
+</pre>
Kannada: 0C82-0C83, 0C85-0C8C, 0C8E-0C90, 0C92-0CA8, 0CAA-0CB3,
<pre>
0CB5-0CB9, 0CBE-0CC4, 0CC6-0CC8, 0CCA-0CCD, 0CDE,
- 0CE0-0CE1</pre>
+ 0CE0-0CE1
+</pre>
Malayalam: 0D02-0D03, 0D05-0D0C, 0D0E-0D10, 0D12-0D28, 0D2A-0D39,
<pre>
- 0D3E-0D43, 0D46-0D48, 0D4A-0D4D, 0D60-0D61</pre>
+ 0D3E-0D43, 0D46-0D48, 0D4A-0D4D, 0D60-0D61
+</pre>
Thai: 0E01-0E3A, 0E40-0E5B
Lao: 0E81-0E82, 0E84, 0E87-0E88, 0E8A, 0E8D, 0E94-0E97,
<pre>
0E99-0E9F, 0EA1-0EA3, 0EA5, 0EA7, 0EAA-0EAB,
0EAD-0EAE, 0EB0-0EB9, 0EBB-0EBD, 0EC0-0EC4, 0EC6,
- 0EC8-0ECD, 0EDC-0EDD</pre>
+ 0EC8-0ECD, 0EDC-0EDD
+</pre>
Tibetan: 0F00, 0F18-0F19, 0F35, 0F37, 0F39, 0F3E-0F47, 0F49-0F69,
<pre>
0F71-0F84, 0F86-0F8B, 0F90-0F95, 0F97, 0F99-0FAD,
- 0FB1-0FB7, 0FB9</pre>
+ 0FB1-0FB7, 0FB9
+</pre>
Georgian: 10A0-10C5, 10D0-10F6
Hiragana: 3041-3093, 309B-309C
Katakana: 30A1-30F6, 30FB-30FC
Digits: 0660-0669, 06F0-06F9, 0966-096F, 09E6-09EF, 0A66-0A6F,
<pre>
0AE6-0AEF, 0B66-0B6F, 0BE7-0BEF, 0C66-0C6F, 0CE6-0CEF,
- 0D66-0D6F, 0E50-0E59, 0ED0-0ED9, 0F20-0F33</pre>
+ 0D66-0D6F, 0E50-0E59, 0ED0-0ED9, 0F20-0F33
+</pre>
Special characters: 00B5, 00B7, 02B0-02B8, 02BB, 02BD-02C1, 02D0-02D1,
<!--page 454 -->
<pre>
02E0-02E4, 037A, 0559, 093D, 0B3D, 1FBE, 203F-2040, 2102,
2107, 210A-2113, 2115, 2118-211D, 2124, 2126, 2128, 212A-2131,
- 2133-2138, 2160-2182, 3005-3007, 3021-3029</pre>
+ 2133-2138, 2160-2182, 3005-3007, 3021-3029
+</pre>
<h2><a name="E" href="#E">Annex E</a></h2>
<p><!--para 1 -->
<pre>
(informative)
-<h6> Implementation limits</h6></pre>
+<h6> Implementation limits</h6>
+</pre>
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
with the same sign. The values shall all be constant expressions suitable for use in #if
#define USHRT_MAX 65535
#define UINT_MAX 65535
#define ULONG_MAX 4294967295
- #define ULLONG_MAX 18446744073709551615</pre>
+ #define ULLONG_MAX 18446744073709551615
+</pre>
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
directives; all floating values shall be constant expressions. The components are
<p><!--para 4 -->
<pre>
#define FLT_EVAL_METHOD
- #define FLT_ROUNDS</pre>
+ #define FLT_ROUNDS
+</pre>
The values given in the following list shall be replaced by implementation-defined
constant expressions that are greater or equal in magnitude (absolute value) to those
shown, with the same sign:
#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>
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:
<p><!--para 6 -->
<pre>
#define DBL_MAX 1E+37
#define FLT_MAX 1E+37
- #define LDBL_MAX 1E+37</pre>
+ #define LDBL_MAX 1E+37
+</pre>
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:
<!--page 456 -->
#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 -->
</ul>
Any non-IEC 60559 extended format used for the long double type shall have more
precision than IEC 60559 double and at least the range of IEC 60559 double.<sup><a href="#note308"><b>308)</b></a></sup>
-<h6> Recommended practice</h6>
+<h6>Recommended practice</h6>
<p><!--para 2 -->
The long double type should match an IEC 60559 extended format.
A contracted expression treats infinities, NaNs, signed zeros, subnormals, and the
rounding directions in a manner consistent with the basic arithmetic operations covered
by IEC 60559.
-<h6> Recommended practice</h6>
+<h6>Recommended practice</h6>
<p><!--para 2 -->
A contracted expression should raise floating-point exceptions in a manner generally
consistent with the basic arithmetic operations. A contracted expression should deliver
<li> The rounding precision mode (if supported) is set so that results are not shortened.
<li> Trapping or stopping (if supported) is disabled on all floating-point exceptions.
</ul>
-<h6> Recommended practice</h6>
+<h6>Recommended practice</h6>
<p><!--para 2 -->
The implementation should produce a diagnostic message for each translation-time
float y = 0.0/0.0; // raises an exception
double z = 0.0/0.0; // raises an exception
/* ... */
- }</pre>
+ }
+</pre>
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.7.5" href="#F.7.5">F.7.5 Initialization</a></h4>
float y = 1.1e75f; // may raise exceptions
long double z = 1.1e75; // does not raise exceptions
/* ... */
- }</pre>
+ }
+</pre>
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
float of the wider value 1.1e75, which raises floating-point exceptions. The automatic initializations
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
the preceding loop could be treated as
<!--page 464 -->
<pre>
- if (0 < n) x + 1;</pre>
+ if (0 < n) x + 1;
+</pre>
<h4><a name="F.8.2" href="#F.8.2">F.8.2 Expression transformations</a></h4>
<p><!--para 1 -->
constants generally do not yield numerically equivalent
expressions, if the constants are exact then such
transformations can be made on IEC 60559 machines
- and others that round perfectly.</pre>
+ and others that round perfectly.
+</pre>
1 * x and x / 1 -> x The expressions 1 * x, x / 1, and x are equivalent
<pre>
- (on IEC 60559 machines, among others).<sup><a href="#note317"><b>317)</b></a></sup></pre>
+ (on IEC 60559 machines, among others).<sup><a href="#note317"><b>317)</b></a></sup>
+</pre>
x / x -> 1.0 The expressions x / x and 1.0 are not equivalent if x
<pre>
- can be zero, infinite, or NaN.</pre>
+ can be zero, infinite, or NaN.
+</pre>
x - y <-> x + (-y) The expressions x - y, x + (-y), and (-y) + x
<pre>
- are equivalent (on IEC 60559 machines, among others).</pre>
+ are equivalent (on IEC 60559 machines, among others).
+</pre>
x - y <-> -(y - x) The expressions x - y and -(y - x) are not
<pre>
equivalent because 1 - 1 is +0 but -(1 - 1) is -0 (in the
- default rounding direction).<sup><a href="#note318"><b>318)</b></a></sup></pre>
+ default rounding direction).<sup><a href="#note318"><b>318)</b></a></sup>
+</pre>
x - x -> 0.0 The expressions x - x and 0.0 are not equivalent if
<pre>
- x is a NaN or infinite.</pre>
+ x is a NaN or infinite.
+</pre>
0 * x -> 0.0 The expressions 0 * x and 0.0 are not equivalent if
<pre>
- x is a NaN, infinite, or -0.</pre>
+ x is a NaN, infinite, or -0.
+</pre>
x + 0->x The expressions x + 0 and x are not equivalent if x is
<pre>
-0, because (-0) + (+0) yields +0 (in the default
- rounding direction), not -0.</pre>
+ rounding direction), not -0.
+</pre>
x - 0->x (+0) - (+0) yields -0 when rounding is downward
<pre>
(toward -(inf)), but +0 otherwise, and (-0) - (+0) always
yields -0; so, if the state of the FENV_ACCESS pragma
is ''off'', promising default rounding, then the
- implementation can replace x - 0 by x, even if x</pre>
+ implementation can replace x - 0 by x, even if x
+</pre>
<!--page 465 -->
<pre>
- might be zero.</pre>
+ might be zero.
+</pre>
-x <-> 0 - x The expressions -x and 0 - x are not equivalent if x
<pre>
is +0, because -(+0) yields -0, but 0 - (+0) yields +0
- (unless rounding is downward).</pre>
+ (unless rounding is downward).
+</pre>
<h6>footnotes</h6>
<p><small><a name="note317" href="#note317">317)</a> Strict support for signaling NaNs -- not required by this specification -- would invalidate these and
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>
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>
+ of the FENV_ACCESS pragma 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
<!--page 466 -->
<pre>
if (isless(a,b))
f();
else
- g();</pre>
+ g();
+</pre>
but is equivalent to
<pre>
if (!(a < b))
g();
else
- f();</pre>
+ f();
+</pre>
<h4><a name="F.8.4" href="#F.8.4">F.8.4 Constant arithmetic</a></h4>
For families of functions, the specifications apply to all of the functions even though only
the principal function is shown. Unless otherwise specified, where the symbol ''(+-)''
occurs in both an argument and the result, the result has the same sign as the argument.
-<h6> Recommended practice</h6>
+<h6>Recommended practice</h6>
<p><!--para 13 -->
If a function with one or more NaN arguments returns a NaN result, the result should be
the same as one of the NaN arguments (after possible type conversion), except perhaps
{
*exp = (value == 0) ? 0 : (int)(1 + logb(value));
return scalbn(value, -(*exp));
- }</pre>
+ }
+</pre>
<h5><a name="F.9.3.5" href="#F.9.3.5">F.9.3.5 The ilogb functions</a></h5>
<p><!--para 1 -->
return copysign(
isinf(value) ? 0.0 :
value - (*iptr), value);
- }</pre>
+ }
+</pre>
<h5><a name="F.9.3.13" href="#F.9.3.13">F.9.3.13 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>
<h5><a name="F.9.6.2" href="#F.9.6.2">F.9.6.2 The floor functions</a></h5>
<p><!--para 1 -->
}
feupdateenv(&save_env);
return result;
- }</pre>
+ }
+</pre>
The round functions may, but are not required to, raise the ''inexact'' floating-point
exception for non-integer numeric arguments, as this implementation does.
result = remainder(fabs(x), (y = fabs(y)));
if (signbit(result)) result += y;
return copysign(result, x);
- }</pre>
+ }
+</pre>
<h5><a name="F.9.7.2" href="#F.9.7.2">F.9.7.2 The remainder functions</a></h5>
<p><!--para 1 -->
The body of the fmax function might be<sup><a href="#note323"><b>323)</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="note323" href="#note323">323)</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>
(informative)
- 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>
<p><!--para 3 -->
<pre>
- x + iy (xu) + i(yu) (-yv) + i(xv)</pre>
+ x + iy (xu) + i(yu) (-yv) + i(xv)
+</pre>
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>
<p><!--para 4 -->
<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>
The * and / operators satisfy the following infinity properties for all real, imaginary, and
complex operands:<sup><a href="#note325"><b>325)</b></a></sup>
<ul>
}
}
return x + I * y;
- }</pre>
+ }
+</pre>
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>
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
overflow and underflow in the calculation of the numerator. Scaling with the scalbn function, instead of
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.
<p><!--para 7 -->
<pre>
cabs(x + iy) = hypot(x, y)
- carg(x + iy) = atan2(y, x)</pre>
+ carg(x + iy) = atan2(y, x)
+</pre>
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):
<p><!--para 8 -->
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>
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
families of functions, the specifications apply to all of the functions even though only the
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 -->
<p><!--para 1 -->
<pre>
(informative)
- Common warnings</pre>
+ Common warnings
+</pre>
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
common situations.
<p><!--para 1 -->
<pre>
(informative)
- Portability issues</pre>
+ Portability issues
+</pre>
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 -->
projects / c-standard / blobdiff