Used by functions with a varying number of arguments of varying
types. The function must declare an object of type va_list which is
used by the macros va_start(3), va_arg(3), va_copy(3),
and va_end(3) to traverse the list of arguments.
STANDARDS
C11, POSIX.1-2008.
HISTORY
C89, POSIX.1-2001.
NOTES
The following headers also provide va_list:
<stdio.h> and <wchar.h>.