The va_arg, va_end, and va_start macros provide access to function arguments when the number of arguments is variable. These macros are defined in STDARG.H for ANSI C compatibility, and in VARARGS.H for compatibility with UNIX System V.
Argument-Access Macros
| Macro | Use |
| va_arg | Retrieve argument from list |
| va_end | Reset pointer |
| va_start | Set pointer to beginning of argument list |