13.2.1 Declare variable arguments

Synopsis

     #include <varargs.h>
     function(va_alist)
     va_dcl

Description
To use the varargs.h version of variable argument lists, you must declare your function with a call to the macro va_alist as its argument list, and use va_dcl as the declaration. Do not use a semicolon after va_dcl.

Returns
These macros cannot be used in a context where a return is syntactically possible.

Portability
va_alist and va_dcl were the most widespread method of declaring variable argument lists prior to ANSI C.