If your C compiler predates ANSI C, you may still be able to use variable argument lists using the macros from the `varargs.h' header file. These macros resemble their ANSI counterparts, but have important differences in usage. In particular, since traditional C has no declaration mechanism for variable argument lists, two additional macros are provided simply for the purpose of defining functions with variable argument lists.
As with `stdarg.h', the type va_list is used to hold a data
structure representing a variable argument list.