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From: mark@spider.co.uk (Mark Valentine)
Newsgroups: comp.unix.wizards
Subject: calling one varargs routine from another (how?!)
Message-ID: <21293@adm.BRL.MIL>
Date: 27 Oct 89 17:56:13 GMT
Sender: news@adm.BRL.MIL
Lines: 60

[If I had USENET postability this would be in comp.lang.c.  But I don't think
 it's entirely a waste of bandwidth here...]

Q:  Is there a portable way, both in ANSI and traditional C, to call a
    varargs function such as

	void error(char *message, ...)

    from another such as

	void fatal(char *message, ...)

    ?  For traditional C, my best guess would be something like

	#include <varargs.h>

	void
	fatal(va_alist)
	va_dcl
	{
		error(va_alist);
		exit(1);
	}

    (which actually worked for my test prog on a MIPS box, but not on a VAX).

    For ANSI C, the nearest I can get to expressing what I want is

	#include <stdarg.h>

	void
	fatal(char *message, ...)
	{
		va_list	args;

		va_start(args, message);
		error(message, args);
		va_end(args);
		exit(1);
	}

    which doesn't work on either the MIPS or VAX!  My test was

	main()
	{
		fatal("%d... %d... %d... bye!\n", 3, 2, 1);
	}

    I feel I'm missing something, but...  It would niggle me to expand a
    six-line error routine in each of a handful of wrappers!  On the other
    hand I guess if this were possible we wouldn't have v*printf().

#if 0
A:
#endif

		Mark.

-- 
Mark Valentine, Spider Systems <mark@spider.co.uk>            /\oo/\