Path: utzoo!dptcdc!jarvis.csri.toronto.edu!mailrus!ncar!ames!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.std.c
Subject: Re: Variable arguments in macros
Message-ID: <10068@smoke.BRL.MIL>
Date: 18 Apr 89 13:41:46 GMT
References: <89Apr17.163342edt.11027@ephemeral.ai.toronto.edu>
Reply-To: gwyn@brl.arpa (Doug Gwyn)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 17

In article <89Apr17.163342edt.11027@ephemeral.ai.toronto.edu> bradb@ai.toronto.edu (Brad Brown) writes:
>I've been trying to find a way to have macros with variable numbers of
>arguments in ANSI C, and I don't think it can be done.

Not as such.

There is a trick that is sometimes convenient (but not in this
particular case):

#define FOO(x) bar x
FOO((a,b,c))	/* expands to: bar (a,b,c) */

>What I'd like to do is have a header file with a macro similar to 
>	#define trace(s)  { fprintf( stderr, s ); }

What I do for this is to define a variable-argument function that
invokes vfprintf() to do the printing.