hpux man page for stdarg

stdarg(5)							File Formats Manual							 stdarg(5)

NAME
       stdarg.h - macros for handling variable argument lists

SYNOPSIS
DESCRIPTION
       The  header contains a set of macros that can be used to write portable procedures that accept variable argument lists.	Routines that have
       variable argument lists (such as but do not use stdarg are inherently nonportable, because different machines use different  argument-pass-
       ing conventions.

       is a type defined for the variable used to traverse the list.

       is called to initialize pvar to the beginning of the list.  The type of argN should be the same as the argument to the function just before
       the variable portion of the argument list.

       returns the next argument in the list pointed to by pvar.  type is the type the argument is expected to be.  Different types can be  mixed,
       but it is up to the routine to know what type of argument is expected, because it cannot be determined at runtime.

       is used to clean up.

       Multiple traversals, each bracketed by ...  are possible.

       NOTE:  The  header  file  supercedes the header, and contains all of the macros.  is provided for compatibility with pre-ANSI compilers and
       earlier releases of HP C/HP-UX.

EXAMPLE
       This example is a possible implementation of (see exec(2)):

	      #include <stdarg.h>
	      #define MAXARGS 100

	      /*  execl is called by
		  execl(file, arg1, arg2, ..., (char *)0);
	      */
	      execl(const char *file, const char *args, ...)
	      {
		  va_list ap;
		  char *array[MAXARGS];
		  int argno = 0;

		  va_start(ap, args);
		  if ((array[0] = args) != 0)
		      while ((array[argno++] = va_arg(ap, char *)) != 0)
			 ;
		  va_end(ap);
		  return execv(file, array);
	      }

WARNINGS
       It is up to the calling routine to specify how many arguments there are, since it is not always possible to determine this from	the  stack
       frame.	For  example,  is  passed  a  zero  pointer to signal the end of the list, and can tell how many arguments are there by the format
       string.

       Unless ANSI C is used, it is non-portable to specify a second argument of char, short, or float to va_arg, because arguments  seen  by  the
       called function are never char, short, or float.

       Pre-ANSI C converts char and short arguments to int and converts float arguments to double before passing them to a function.

SEE ALSO
       exec(2), vprintf(3S), varargs(5).

STANDARDS CONFORMANCE
																	 stdarg(5)