Path: utzoo!attcan!uunet!ingr!jones
From: jones@ingr.UUCP (Mark Jones)
Newsgroups: comp.std.c
Subject: Re: Variable length arg lists for macros
Summary: How about this way
Message-ID: <2517@ingr.UUCP>
Date: 8 Sep 88 16:28:38 GMT
References: <438@ucsvc.unimelb.edu.au> <3604@phoenix.Princeton.EDU>
Organization: Intergraph Corp. Huntsville, Al
Lines: 45

In article <3604@phoenix.Princeton.EDU>, haahr@phoenix.Princeton.EDU (Paul Gluckauf Haahr) writes:
> > How do people feel about the idea of preprocessor macros with variable
> > length argument lists ?
> > 
> > However this can not be done with macro calls. Wouldn't it be nice to be
> > able to do something like ...
> > 
> > 
> > 	#ifdef TRACE
> > 	#define	tracef(s,...)	printf(s,...)
> > 	#else
> > 	#define	tracef(s,...)	/* nothing */
> > 	#endif
> > 
> > At present, this CANNOT BE DONE, without nesting parentheses (clumsy) or
> > using a call to an empty function (inefficient, unless you have inline
> > integration in an optimizing compiler).


If you want a trace function, try this one

#ifdef TRACE
#define TR(x) x
#else
#define TR(x)
#endif

	Now, you can just say
	

	.
	.
	.
	TR(printf("entering buggy function"));
	.
	.
	.

and all is well!


Bought from Dr Dobbs Journal, Only good thing to come out of that
magazine in months.(Did BYTE buy them out?)  <-- Rhetorical question

Mark Jones