Path: utzoo!attcan!uunet!husc6!rutgers!att!ulysses!andante!alice!ark
From: ark@alice.UUCP (Andrew Koenig)
Newsgroups: comp.lang.c
Subject: Re: passing variable numbers of arguments
Message-ID: <8699@alice.UUCP>
Date: 7 Jan 89 16:57:33 GMT
References: <899@thor.stolaf.edu>
Distribution: na
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 61

In article <899@thor.stolaf.edu>, mackenzi@agnes.uucp (David MacKenzie) writes:

> The following program produces unexpected results:

> #include <varargs.h>

> main ()
> {
>   printf ("foo:\n");
>   foo (1, 2, 3, 0);
>   printf ("bar:\n");
>   bar (4, 5, 6, 0);
> }

> foo (va_alist)
>   va_dcl
> {
>   bar (va_alist);
> }

> bar (va_alist)
>   va_dcl
> {
>   va_list list;
>   int i;

>   va_start (list);
>   while (i = va_arg (list, int))
>     printf ("%d\n", i);
>   va_end (list);
> }

There is no way to pass your entire argument list to another function.
The closest you can come is to pass a va_list.  For example:

main ()
{
  printf ("foo:\n");
  foo (1, 2, 3, 0);
}

foo (va_alist)
  va_dcl
{
  va_list list;
  va_start (list);
  bar (list);
  va_end (list);
}

bar (x)
  va_list x;
{
  int i;

  while (i = va_arg (x, int))
    printf ("%d\n", i);
}
-- 
				--Andrew Koenig
				  ark@europa.att.com