Initialize variable argument list

Synopsis

#include <stdarg.h>
void va_start(va_list ap, rightmost);
```### Description

Use va_start to initialize the variable argument list ap, so that va_arg can extract values from it. rightmost is the name of the last explicit argument in the parameter list (the argument immediately preceding the ellipsis `...' that flags variable arguments in an ANSI C function header). You can only use va_start in a function declared using this ellipsis notation (not, for example, in one of its subfunctions).### Returns

va_start does not return a result.

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**Authoritative source**: BUSMASTER DITA help source `va_start.dita`, compiled into `BUSMASTER.CHM` with the application.