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From: wcs@ho95e.ATT.COM (Bill.Stewart)
Newsgroups: comp.lang.c
Subject: Re: How can I use #define to make something completely disappear?
Message-ID: <1852@ho95e.ATT.COM>
Date: Sun, 8-Nov-87 18:44:39 EST
Article-I.D.: ho95e.1852
Posted: Sun Nov  8 18:44:39 1987
Date-Received: Thu, 12-Nov-87 04:41:34 EST
References: <10083@brl-adm.ARPA> <850@tut.cis.ohio-state.edu> <9187@mimsy.UUCP> <3037@bunker.UUCP>
Reply-To: wcs@ho95e.UUCP (46133-Bill.Stewart,2G218,x0705,)
Organization: AT&T Bell Labs 46133, Holmdel, NJ
Lines: 16

> DEBUGPRINT( "format %s", arg1, arg2, ...);
A crude approach is
	#ifdef DEBUG
	#define DEBUGPRINT printf
	#else
	#define DEBUGPRINTF (void)
	#endif
This will always evaluate the argument list, which is undesirable if
some of the arguments have side-effects (e.g. i++ ).
An alternative is to use
	#define DEBUGPRINTF 0 &&
which should short-circuit evaluation of the ( .. , .. ) list.
(Lint may not give you any respect, but...).
-- 
#				Thanks;
# Bill Stewart, AT&T Bell Labs 2G218, Holmdel NJ 1-201-949-0705 ihnp4!ho95c!wcs