[cstdarg.syn]

# 17 Language support library [[support]](./#support)

## 17.14 Other runtime support [[support.runtime]](support.runtime#cstdarg.syn)

### 17.14.2 Header <cstdarg> synopsis [cstdarg.syn]

[🔗](#header:%3ccstdarg%3e)

// all freestanding#define __STDC_VERSION_STDARG_H__ 202311Lnamespace std {using [va_list](#lib:va_list "17.14.2 Header <cstdarg> synopsis [cstdarg.syn]") = *see below*;}#define va_arg(V, P) *see below*#define va_copy(VDST, VSRC) *see below*#define va_end(V) *see below*#define va_start(V, ...) *see below*

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L6396)

The contents of the header <cstdarg> are the same as the C
standard library header [<stdarg.h>](support.c.headers.general#header:%3cstdarg.h%3e "17.15.1 General [support.c.headers.general]"), with the following changes:

- [(1.1)](#1.1)

  In lieu of the default argument promotions specified in ISO/IEC 9899:2024 6.5.2.2,
the definition in [[expr.call]](expr.call "7.6.1.3 Function call") applies[.](#1.1.sentence-1)

- [(1.2)](#1.2)

  The preprocessing tokens
comprising the second and subsequent arguments to va_start (if any)
are discarded[.](#1.2.sentence-1)
  [*Note [1](#note-1)*:
  va_start accepts a second argument
for compatibility with prior revisions of C++[.](#1.2.sentence-2)
 — *end note*]

See also: ISO/IEC 9899:2024, 7.16