va_start()

Updated: April 19, 2023

Start getting items from a variable argument list

Synopsis:

#include <stdarg.h>

void va_start( va_list param, 
               previous );

Arguments:

param
A va_list object that the “varargs” macros can use to locate the arguments.
previous
The argument that immediately precedes the "..." notation in the original function definition.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

Use the va_start() macro to start the acquisition of arguments from a list of variable arguments.

You must use the va_start() macro with the associated macros va_arg(), va_copy(), and va_end(). For each call to va_start(), you must have a matching call to va_end(). For more information, see va_arg().

Examples:

See va_arg().

Classification:

POSIX 1003.1

Safety:  
Cancellation point No
Interrupt handler Yes
Signal handler Yes
Thread Yes

Caveats:

va_start() is a macro.