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From: jeff@samna.UUCP (jeff)
Newsgroups: comp.lang.c
Subject: Re: Commas in macro arguments
Message-ID: <246@samna.UUCP>
Date: 28 Mar 90 21:26:59 GMT
References: <1990Mar22.203048.18491@dde.dk> <1990Mar23.164301.14975@utzoo.uucp> <T9H20-9ggpc2@ficc.uu.net>
Reply-To: jeff@samna.UUCP ()
Organization: Draughtsman's Contractors
Lines: 33

In article <T9H20-9ggpc2@ficc.uu.net> peter@ficc.uu.net (Peter da Silva) writes:
>> >#define call(a,b)	a(b)
>
>> >I can use that to call a function with one argument. How can I use
>> >it to call a function with two arguments?
>
>Sometimes you can, depending on how much you want to munge the arguments:
>
>#define call(a,b) a b
>
>call(a,(b))
>call(c,(d,e))

I sometimes use this mechanism to put debugging printf's in source
files (Can be used for any variable argument macro).

Debugging statements are written like this:

	DPRINTF(("Variable x=%d, y=%d, z=%d\n", x, y, z));


Then in a header file:

#ifdef	DEBUG
#	define	DPRINTF(s) printf s
#else
#	define	DPRINTF(s)
#endif


Sometimes it's kinda hard to remember the extra set of parentheses, but...

Jeff