DBL_MIN 1E-37
LDBL_MIN 1E-37</pre>
</ul>
- Recommended practice
+<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.
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>
- { expressionopt }</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
represented by successive bits are additive, begin with 1, and are multiplied by successive integral
powers of 2, except perhaps the bit with the highest position. (Adapted from the American National
Dictionary for Information Processing Systems.) A byte contains CHAR_BIT bits, and the values of
- type unsigned char range from 0 to 2
-
-<pre>
- CHAR_BIT
- - 1.</pre>
+ type unsigned char range from 0 to 2<sup>CHAR_BIT</sup>- 1.
</small>
<p><small><a name="note41" href="#note41">41)</a> Thus, an automatic variable can be initialized to a trap representation without causing undefined
behavior, but the value of the variable cannot be used until a proper value is stored in it.
For unsigned integer types other than unsigned char, the bits of the object
representation shall be divided into two groups: value bits and padding bits (there need
not be any of the latter). If there are N value bits, each bit shall represent a different
- power of 2 between 1 and 2 N -1 , so that objects of that type shall be capable of
- representing values from 0 to 2 N - 1 using a pure binary representation; this shall be
+ power of 2 between 1 and 2<sup>N-1</sup> , so that objects of that type shall be capable of
+ representing values from 0 to 2<sup>N</sup> - 1 using a pure binary representation; this shall be
known as the value representation. The values of any padding bits are unspecified.<sup><a href="#note44"><b>44)</b></a></sup>
<p><!--para 2 -->
For signed integer types, the bits of the object representation shall be divided into three
modified in one of the following ways:
<ul>
<li> the corresponding value with sign bit 0 is negated (sign and magnitude);
-<li> the sign bit has the value -(2 N ) (two's complement);
-<li> the sign bit has the value -(2 N - 1) (ones' complement ).
+<li> the sign bit has the value -(2<sup>N</sup> ) (two's complement);
+<li> the sign bit has the value -(2<sup>N</sup> - 1) (ones' complement ).
</ul>
Which of these applies is implementation-defined, as is whether the value with sign bit 1
and all value bits zero (for the first two), or with sign bit and all value bits 1 (for ones'
and complex otherwise. This pattern is called the usual arithmetic conversions:
<!--page 57 -->
<p><!--para 2 -->
-<pre>
- First, if the corresponding real type of either operand is long double, the other
+<ul>
+<li> First, if the corresponding real type of either operand is long double, the other
operand is converted, without change of type domain, to a type whose
corresponding real type is long double.
- Otherwise, if the corresponding real type of either operand is double, the other
+<li> Otherwise, if the corresponding real type of either operand is double, the other
operand is converted, without change of type domain, to a type whose
corresponding real type is double.
- Otherwise, if the corresponding real type of either operand is float, the other
+<li> Otherwise, if the corresponding real type of either operand is float, the other
operand is converted, without change of type domain, to a type whose
corresponding real type is float.<sup><a href="#note51"><b>51)</b></a></sup>
- Otherwise, the integer promotions are performed on both operands. Then the
+<li> Otherwise, the integer promotions are performed on both operands. Then the
following rules are applied to the promoted operands:
- If both operands have the same type, then no further conversion is needed.
- Otherwise, if both operands have signed integer types or both have unsigned
+<ul>
+<li> If both operands have the same type, then no further conversion is needed.
+<li> Otherwise, if both operands have signed integer types or both have unsigned
integer types, the operand with the type of lesser integer conversion rank is
converted to the type of the operand with greater rank.
- Otherwise, if the operand that has unsigned integer type has rank greater or
+<li> Otherwise, if the operand that has unsigned integer type has rank greater or
equal to the rank of the type of the other operand, then the operand with
signed integer type is converted to the type of the operand with unsigned
integer type.
- Otherwise, if the type of the operand with signed integer type can represent
+<li> Otherwise, if the type of the operand with signed integer type can represent
all of the values of the type of the operand with unsigned integer type, then
the operand with unsigned integer type is converted to the type of the
operand with signed integer type.
- Otherwise, both operands are converted to the unsigned integer type
- corresponding to the type of the operand with signed integer type.</pre>
+<li> Otherwise, both operands are converted to the unsigned integer type
+ corresponding to the type of the operand with signed integer type.
+</ul>
+</ul>
The values of floating operands and of the results of floating expressions may be
represented in greater precision and range than that required by the type; the types are not
changed thereby.<sup><a href="#note52"><b>52)</b></a></sup>
<!--page 64 -->
- Implementation limits
+<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
<!--page 67 -->
<pre>
integer-constant:
- decimal-constant integer-suffixopt
- octal-constant integer-suffixopt
- hexadecimal-constant integer-suffixopt
+ decimal-constant integer-suffix<sub>opt</sub>
+ octal-constant integer-suffix<sub>opt</sub>
+ hexadecimal-constant integer-suffix<sub>opt</sub>
decimal-constant:
nonzero-digit
decimal-constant digit
a b c d e f
A B C D E F
integer-suffix:
- unsigned-suffix long-suffixopt
+ unsigned-suffix long-suffix<sub>opt</sub>
unsigned-suffix long-long-suffix
- long-suffix unsigned-suffixopt
- long-long-suffix unsigned-suffixopt
+ long-suffix unsigned-suffix<sub>opt</sub>
+ long-long-suffix unsigned-suffix<sub>opt</sub>
unsigned-suffix: one of
u U
long-suffix: one of
The type of an integer constant is the first of the corresponding list in which its value can
be represented.
<!--page 68 -->
-<pre>
- Octal or Hexadecimal</pre>
- Suffix Decimal Constant Constant
-
- none int int
-<pre>
- long int unsigned int
- long long int long int
- unsigned long int
- long long int
- unsigned long long int</pre>
-
- u or U unsigned int unsigned int
-<pre>
- unsigned long int unsigned long int
- unsigned long long int unsigned long long int</pre>
-
- l or L long int long int
-<pre>
- long long int unsigned long int
- long long int
- unsigned long long int</pre>
-
- Both u or U unsigned long int unsigned long int
- and l or L unsigned long long int unsigned long long int
-
- ll or LL long long int long long int
-<pre>
- unsigned long long int</pre>
-
- Both u or U unsigned long long int unsigned long long int
- and ll or LL
+<table border=1>
+<tr><th> Suffix <th>Decimal Constant <th>Octal or Hexadecimal Constant
+<tr><td> none
+<td><pre>int
+long int
+long long int</pre>
+<td><pre>int
+unsigned int
+long int
+unsigned long int
+long long int
+unsigned long long int</pre>
+<tr><td> u or U
+<td><pre>unsigned int
+unsigned long int
+unsigned long long int</pre>
+<td><pre>unsigned int
+unsigned long int
+unsigned long long int</pre>
+<tr><td> l or L
+<td><pre>long int
+long long int</pre>
+<td><pre>long int
+unsigned long int
+long long int
+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>
+<tr><td> ll or LL
+<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>
+</table>
<p><!--para 6 -->
If an integer constant cannot be represented by any type in its list, it may have an
extended integer type, if the extended integer type can represent its value. If all of the
decimal-floating-constant
hexadecimal-floating-constant
decimal-floating-constant:
- fractional-constant exponent-partopt floating-suffixopt
- digit-sequence exponent-part floating-suffixopt
+ fractional-constant exponent-part<sub>opt</sub> floating-suffix<sub>opt</sub>
+ digit-sequence exponent-part floating-suffix<sub>opt</sub>
hexadecimal-floating-constant:
hexadecimal-prefix hexadecimal-fractional-constant
- binary-exponent-part floating-suffixopt
+ binary-exponent-part floating-suffix<sub>opt</sub>
hexadecimal-prefix hexadecimal-digit-sequence
- binary-exponent-part floating-suffixopt
+ binary-exponent-part floating-suffix<sub>opt</sub>
fractional-constant:
- digit-sequenceopt . digit-sequence
+ digit-sequence<sub>opt</sub> . digit-sequence
digit-sequence .
exponent-part:
- e signopt digit-sequence
- E signopt digit-sequence
+ e sign<sub>opt</sub> digit-sequence
+ E sign<sub>opt</sub> digit-sequence
sign: one of
+ -
digit-sequence:
digit
digit-sequence digit
hexadecimal-fractional-constant:
- hexadecimal-digit-sequenceopt .
+ hexadecimal-digit-sequence<sub>opt</sub> .
hexadecimal-digit-sequence
hexadecimal-digit-sequence .
binary-exponent-part:
- p signopt digit-sequence
- P signopt digit-sequence
+ p sign<sub>opt</sub> digit-sequence
+ P sign<sub>opt</sub> digit-sequence
hexadecimal-digit-sequence:
hexadecimal-digit
hexadecimal-digit-sequence hexadecimal-digit
Floating constants are converted to internal format as if at translation-time. The
conversion of a floating constant shall not raise an exceptional condition or a floating-
point exception at execution time.
- Recommended practice
+<h6>Recommended practice</h6>
<p><!--para 6 -->
The implementation should produce a diagnostic message if a hexadecimal constant
cannot be represented exactly in its evaluation format; the implementation should then
<p><!--para 1 -->
<pre>
string-literal:
- " s-char-sequenceopt "
- L" s-char-sequenceopt "
+ " s-char-sequence<sub>opt</sub> "
+ L" s-char-sequence<sub>opt</sub> "
s-char-sequence:
s-char
s-char-sequence s-char
<pre>
i = ++i + 1;
- a[i++] = i;
+ a[i++] = i;</pre>
while allowing
+<pre>
i = i + 1;
a[i] = i;</pre>
parentheses () (<a href="#6.5.1">6.5.1</a>), subscripting brackets [] (<a href="#6.5.2.1">6.5.2.1</a>), function-call parentheses () (<a href="#6.5.2.2">6.5.2.2</a>), and
the conditional operator ?: (<a href="#6.5.15">6.5.15</a>).
-<pre>
- Within each major subclause, the operators have the same precedence. Left- or right-associativity is
- indicated in each subclause by the syntax for the expressions discussed therein.</pre>
+ Within each major subclause, the operators have the same precedence. Left- or right-associativity is
+ indicated in each subclause by the syntax for the expressions discussed therein.
</small>
<p><small><a name="note75" href="#note75">75)</a> Allocated objects have no declared type.
</small>
<p><!--para 1 -->
<pre>
declaration:
- declaration-specifiers init-declarator-listopt ;
+ declaration-specifiers init-declarator-list<sub>opt</sub> ;
declaration-specifiers:
- storage-class-specifier declaration-specifiersopt
- type-specifier declaration-specifiersopt
- type-qualifier declaration-specifiersopt
- function-specifier declaration-specifiersopt
+ storage-class-specifier declaration-specifiers<sub>opt</sub>
+ type-specifier declaration-specifiers<sub>opt</sub>
+ type-qualifier declaration-specifiers<sub>opt</sub>
+ function-specifier declaration-specifiers<sub>opt</sub>
init-declarator-list:
init-declarator
init-declarator-list , init-declarator
<p><!--para 1 -->
<pre>
struct-or-union-specifier:
- struct-or-union identifieropt { struct-declaration-list }
+ struct-or-union identifier<sub>opt</sub> { struct-declaration-list }
struct-or-union identifier
struct-or-union:
struct
struct-declaration:
specifier-qualifier-list struct-declarator-list ;
specifier-qualifier-list:
- type-specifier specifier-qualifier-listopt
- type-qualifier specifier-qualifier-listopt
+ type-specifier specifier-qualifier-list<sub>opt</sub>
+ type-qualifier specifier-qualifier-list<sub>opt</sub>
struct-declarator-list:
struct-declarator
struct-declarator-list , struct-declarator
struct-declarator:
declarator
- declaratoropt : 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 1 -->
<pre>
enum-specifier:
- enum identifieropt { enumerator-list }
- enum identifieropt { enumerator-list , }
+ enum identifier<sub>opt</sub> { enumerator-list }
+ enum identifier<sub>opt</sub> { enumerator-list , }
enum identifier
enumerator-list:
enumerator
<p><!--para 6 -->
A type specifier of the form
<pre>
- struct-or-union identifieropt { struct-declaration-list }</pre>
+ struct-or-union identifier<sub>opt</sub> { struct-declaration-list }</pre>
or
<pre>
enum identifier { enumerator-list }</pre>
<p><!--para 1 -->
<pre>
declarator:
- pointeropt direct-declarator
+ pointer<sub>opt</sub> direct-declarator
direct-declarator:
identifier
( declarator )
- direct-declarator [ type-qualifier-listopt assignment-expressionopt ]
- direct-declarator [ static type-qualifier-listopt assignment-expression ]
+ direct-declarator [ type-qualifier-list<sub>opt</sub> assignment-expression<sub>opt</sub> ]
+ direct-declarator [ static type-qualifier-list<sub>opt</sub> assignment-expression ]
direct-declarator [ type-qualifier-list static assignment-expression ]
- direct-declarator [ type-qualifier-listopt * ]
+ direct-declarator [ type-qualifier-list<sub>opt</sub> * ]
direct-declarator ( parameter-type-list )
- direct-declarator ( identifier-listopt )
+ direct-declarator ( identifier-list<sub>opt</sub> )
pointer:
- * type-qualifier-listopt
- * type-qualifier-listopt pointer
+ * type-qualifier-list<sub>opt</sub>
+ * type-qualifier-list<sub>opt</sub> pointer
type-qualifier-list:
type-qualifier
type-qualifier-list type-qualifier
parameter-list , parameter-declaration
parameter-declaration:
declaration-specifiers declarator
- declaration-specifiers abstract-declaratoropt
+ declaration-specifiers abstract-declarator<sub>opt</sub>
identifier-list:
identifier
identifier-list , identifier</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.
- Implementation limits
+<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-listopt 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.
<p><!--para 3 -->
If, in the declaration ''T D1'', D1 has one of the forms:
<pre>
- D[ type-qualifier-listopt assignment-expressionopt ]
- D[ static type-qualifier-listopt assignment-expression ]
+ D[ type-qualifier-list<sub>opt</sub> assignment-expressionopt ]
+ D[ static type-qualifier-list<sub>opt</sub> assignment-expression ]
D[ type-qualifier-list static assignment-expression ]
- D[ type-qualifier-listopt * ]</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.)
or
<!--page 131 -->
<pre>
- D( identifier-listopt )</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 1 -->
<pre>
type-name:
- specifier-qualifier-list abstract-declaratoropt
+ specifier-qualifier-list abstract-declarator<sub>opt</sub>
abstract-declarator:
pointer
- pointeropt direct-abstract-declarator
+ pointer<sub>opt</sub> direct-abstract-declarator
direct-abstract-declarator:
( abstract-declarator )
- direct-abstract-declaratoropt [ type-qualifier-listopt
- assignment-expressionopt ]
- direct-abstract-declaratoropt [ static type-qualifier-listopt
+ direct-abstract-declarator<sub>opt</sub> [ type-qualifier-list<sub>opt</sub>
+ assignment-expression<sub>opt</sub> ]
+ direct-abstract-declarator<sub>opt</sub> [ static type-qualifier-list<sub>opt</sub>
assignment-expression ]
- direct-abstract-declaratoropt [ type-qualifier-list static
+ direct-abstract-declarator<sub>opt</sub> [ type-qualifier-list static
assignment-expression ]
- direct-abstract-declaratoropt [ * ]
- direct-abstract-declaratoropt ( parameter-type-listopt )</pre>
+ direct-abstract-declarator<sub>opt</sub> [ * ]
+ 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
{ initializer-list , }
initializer-list:
designationopt initializer
- initializer-list , designationopt initializer
+ initializer-list , designation<sub>opt</sub> initializer
designation:
designator-list =
designator-list:
<p><!--para 1 -->
<pre>
compound-statement:
- { block-item-listopt }
+ { block-item-list<sub>opt</sub> }
block-item-list:
block-item
block-item-list block-item
<p><!--para 1 -->
<pre>
expression-statement:
- expressionopt ;</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
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.
- Implementation limits
+<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.
iteration-statement:
while ( expression ) statement
do statement while ( expression ) ;
- for ( expressionopt ; expressionopt ; expressionopt ) statement
- for ( declaration expressionopt ; expressionopt ) statement</pre>
+ 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>
<h6>Constraints</h6>
<p><!--para 2 -->
The controlling expression of an iteration statement shall have scalar type.
goto identifier ;
continue ;
break ;
- return expressionopt ;</pre>
+ return expression<sub>opt</sub> ;</pre>
<h6>Semantics</h6>
<p><!--para 2 -->
A jump statement causes an unconditional jump to another place.
<li> The general initialization code is too large to warrant duplication.
<li> The code to determine the next operation is at the head of the loop. (To allow it to be reached by
continue statements, for example.)
+<pre>
/* ... */
goto first_time;
for (;;) {
-<pre>
// determine next operation
/* ... */
if (need to reinitialize) {
continue;
}
// handle other operations
- /* ... */</pre>
- }
+ /* ... */
+ }</pre>
<!--page 150 -->
</ol>
<p><!--para 4 -->
A continue statement causes a jump to the loop-continuation portion of the smallest
enclosing iteration statement; that is, to the end of the loop body. More precisely, in each
of the statements
- while (/* ... */) { do { for (/* ... */) {
<pre>
+ while (/* ... */) { do { for (/* ... */) {
/* ... */ /* ... */ /* ... */
continue; continue; continue;
- /* ... */ /* ... */ /* ... */</pre>
+ /* ... */ /* ... */ /* ... */
contin: ; contin: ; contin: ;
- } } while (/* ... */); }
+ } } 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>
<p><!--para 1 -->
<pre>
function-definition:
- declaration-specifiers declarator declaration-listopt compound-statement
+ declaration-specifiers declarator declaration-list<sub>opt</sub> compound-statement
declaration-list:
declaration
declaration-list declaration</pre>
<!--page 158 -->
<pre>
preprocessing-file:
- groupopt
+ group<sub>opt</sub>
group:
group-part
group group-part
text-line
# non-directive
if-section:
- if-group elif-groupsopt else-groupopt endif-line
+ if-group elif-groups<sub>opt</sub> else-group<sub>opt</sub> endif-line
if-group:
- # if constant-expression new-line groupopt
- # ifdef identifier new-line groupopt
- # ifndef identifier new-line groupopt
+ # if constant-expression new-line group<sub>opt</sub>
+ # ifdef identifier new-line group<sub>opt</sub>
+ # ifndef identifier new-line group<sub>opt</sub>
elif-groups:
elif-group
elif-groups elif-group
elif-group:
- # elif constant-expression new-line groupopt
+ # elif constant-expression new-line group<sub>opt</sub>
else-group:
- # else new-line groupopt
+ # else new-line group<sub>opt</sub>
endif-line:
# endif new-line
control-line:
# include pp-tokens new-line
# define identifier replacement-list new-line
- # define identifier lparen identifier-listopt )
+ # 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
# undef identifier new-line
# line pp-tokens new-line
- # error pp-tokensopt new-line
- # pragma pp-tokensopt new-line
+ # error pp-tokens<sub>opt</sub> new-line
+ # pragma pp-tokens<sub>opt</sub> new-line
# new-line
text-line:
- pp-tokensopt new-line
+ pp-tokens<sub>opt</sub> new-line
non-directive:
pp-tokens new-line
lparen:
a ( character not immediately preceded by white-space
replacement-list:
- pp-tokensopt
+ pp-tokens<sub>opt</sub>
pp-tokens:
preprocessing-token
pp-tokens preprocessing-token
<p><!--para 3 -->
Preprocessing directives of the forms
<pre>
- # if constant-expression new-line groupopt
- # elif constant-expression new-line groupopt</pre>
+ # if constant-expression new-line group<sub>opt</sub>
+ # 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 groupopt
- # ifndef identifier new-line groupopt</pre>
+ # ifdef identifier new-line group<sub>opt</sub>
+ # 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.
</small>
<p><small><a name="note146" href="#note146">146)</a> Thus, the constant expression in the following #if directive and if statement is not guaranteed to
evaluate to the same value in these two contexts.
+<pre>
#if 'z' - 'a' == 25
- if ('z' - 'a' == 25)
+ 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 10 -->
A preprocessing directive of the form
<pre>
- # define identifier lparen identifier-listopt ) replacement-list new-line
+ # 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>
defines a function-like macro with parameters, whose use is similar syntactically to a
<p><!--para 4 -->
A preprocessing directive of the form
<pre>
- # line digit-sequence "s-char-sequenceopt" 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 -->
<p><!--para 1 -->
A preprocessing directive of the form
<pre>
- # error pp-tokensopt 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-tokensopt 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
<h4><a name="6.10.8" href="#6.10.8">6.10.8 Predefined macro names</a></h4>
<p><!--para 1 -->
The following macro names<sup><a href="#note154"><b>154)</b></a></sup> shall be defined by the implementation:
- __DATE__ The date of translation of the preprocessing translation unit: a character
-<pre>
+<dl>
+<dt> __DATE__ <dd>The date of translation of the preprocessing translation unit: a character
string literal of the form "Mmm dd yyyy", where the names of the
months are the same as those generated by the asctime function, and the
first character of dd is a space character if the value is less than 10. If the
date of translation is not available, an implementation-defined valid date
- shall be supplied.</pre>
- __FILE__ The presumed name of the current source file (a character string literal).<sup><a href="#note155"><b>155)</b></a></sup>
- __LINE__ The presumed line number (within the current source file) of the current
-<pre>
- source line (an integer constant).155)</pre>
- __STDC__ The integer constant 1, intended to indicate a conforming implementation.
- __STDC_HOSTED__ The integer constant 1 if the implementation is a hosted
-<pre>
- implementation or the integer constant 0 if it is not.</pre>
- __STDC_MB_MIGHT_NEQ_WC__ The integer constant 1, intended to indicate that, in
-<pre>
+ shall be supplied.
+<dt> __FILE__ <dd>The presumed name of the current source file (a character string literal).<sup><a href="#note155"><b>155)</b></a></sup>
+<dt> __LINE__ <dd>The presumed line number (within the current source file) of the current
+ source line (an integer constant).<sup><a href="#note155"><b>155)</b></a></sup>
+<dt> __STDC__ <dd>The integer constant 1, intended to indicate a conforming implementation.
+<dt> __STDC_HOSTED__ <dd>The integer constant 1 if the implementation is a hosted
+ implementation or the integer constant 0 if it is not.
+<dt> __STDC_MB_MIGHT_NEQ_WC__ <dd>The integer constant 1, intended to indicate that, in
the encoding for wchar_t, a member of the basic character set need not
have a code value equal to its value when used as the lone character in an
- integer character constant.</pre>
- __STDC_VERSION__ The integer constant 199901L.<sup><a href="#note156"><b>156)</b></a></sup>
- __TIME__ The time of translation of the preprocessing translation unit: a character
-<pre>
+ integer character constant.
+<dt> __STDC_VERSION__ <dd>The integer constant 199901L.<sup><a href="#note156"><b>156)</b></a></sup>
+<dt> __TIME__ <dd>The time of translation of the preprocessing translation unit: a character
string literal of the form "hh:mm:ss" as in the time generated by the
asctime function. If the time of translation is not available, an
- implementation-defined valid time shall be supplied.</pre>
-
+ implementation-defined valid time shall be supplied.
+</dl>
<!--page 173 -->
<p><!--para 2 -->
The following macro names are conditionally defined by the implementation:
- __STDC_IEC_559__ The integer constant 1, intended to indicate conformance to the
-<pre>
- specifications in <a href="#F">annex F</a> (IEC 60559 floating-point arithmetic).</pre>
- __STDC_IEC_559_COMPLEX__ The integer constant 1, intended to indicate
-<pre>
+<dl>
+<dt> __STDC_IEC_559__ <dd>The integer constant 1, intended to indicate conformance to the
+ specifications in <a href="#F">annex F</a> (IEC 60559 floating-point arithmetic).
+<dt> __STDC_IEC_559_COMPLEX__ <dd>The integer constant 1, intended to indicate
adherence to the specifications in informative <a href="#G">annex G</a> (IEC 60559
- compatible complex arithmetic).</pre>
- __STDC_ISO_10646__ An integer constant of the form yyyymmL (for example,
-<p><!--para 3 -->
-<pre>
+ compatible complex arithmetic).
+<dt> __STDC_ISO_10646__ <dd>An integer constant of the form yyyymmL (for example,
199712L). If this symbol is defined, then every character in the Unicode
required set, when stored in an object of type wchar_t, has the same
value as the short identifier of that character. The Unicode required set
consists of all the characters that are defined by ISO/IEC 10646, along with
all amendments and technical corrigenda, as of the specified year and
- month.</pre>
+ month.
+</dl>
+<p><!--para 3 -->
The values of the predefined macros (except for __FILE__ and __LINE__) remain
constant throughout the translation unit.
<p><!--para 4 -->
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.)
- Recommended practice
+<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
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.
- Recommended practice
+<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 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.
- Recommended practice
+<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
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.
- Recommended practice
+<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
<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.
- Recommended practice
+<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
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.
- Recommended practice
+<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
<p><!--para 1 -->
<pre>
(informative)
- Implementation limits</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
</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>
- Recommended practice
+<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.
- Recommended practice
+<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>
- Recommended practice
+<h6> Recommended practice</h6>
<p><!--para 2 -->
The implementation should produce a diagnostic message for each translation-time
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.
- Recommended practice
+<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
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