#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.
Portability
ANSI C requires va_start.