Difference between revisions of "cpp/header/cstdarg"
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| − | This header provides support for [[cpp/utility/variadic|C-style variadic functions]]. | + | This header provides support for [[cpp/utility/variadic|C-style variadic functions]], while the [[c/language/conversion#Default argument promotions|C definition]] of "default argument promotions" is replaced with the [[cpp/language/variadic arguments#Default conversions|C++ definition]]. |
{{dsc begin}} | {{dsc begin}} | ||
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{{source|1= | {{source|1= | ||
namespace std { | namespace std { | ||
| − | using va_list = /* | + | using va_list = /*see description*/ ; |
} | } | ||
| − | + | #define va_arg(V, P) /*see description*/ | |
| − | #define va_arg(V, P) /* | + | #define va_copy(VDST, VSRC) /*see description*/ |
| − | #define va_copy(VDST, VSRC) /* | + | #define va_end(V) /*see description*/ |
| − | #define va_end(V) /* | + | #define va_start(V, P) /*see description*/ |
| − | #define va_start(V, P) /* | + | |
}} | }} | ||
| + | |||
| + | ===Defect reports=== | ||
| + | {{dr list begin}} | ||
| + | {{dr list item|wg=cwg|dr=2645|std=C++98|before=C++ defines "default argument promotions", but its C definition was used|after=the C++ definition overrides the C definition}} | ||
| + | {{dr list end}} | ||
| + | |||
| + | {{langlinks|es|ja|ru|zh}} | ||
Latest revision as of 04:22, 20 January 2023
This header was originally in the C standard library as <stdarg.h>.
This header provides support for C-style variadic functions, while the C definition of "default argument promotions" is replaced with the C++ definition.
Types | ||
| holds the information needed by va_start, va_arg, va_end, and va_copy (typedef) | ||
Macros | ||
| enables access to variadic function arguments (function macro) | ||
| accesses the next variadic function argument (function macro) | ||
| (C++11) |
makes a copy of the variadic function arguments (function macro) | |
| ends traversal of the variadic function arguments (function macro) | ||
[edit] Synopsis
namespace std { using va_list = /*see description*/ ; } #define va_arg(V, P) /*see description*/ #define va_copy(VDST, VSRC) /*see description*/ #define va_end(V) /*see description*/ #define va_start(V, P) /*see description*/
[edit] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| CWG 2645 | C++98 | C++ defines "default argument promotions", but its C definition was used | the C++ definition overrides the C definition |
