Initialize variable argument list

Synopsis

#include <varargs.h>
va_list ap; va_start(ap);
```### Description

With the `varargs.h' macros, use va_start to initialize a data structure ap to permit manipulating a variable argument list. ap must have the type va_alist.### 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.