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From: ljz@fxgrp.UUCP
Newsgroups: comp.lang.c
Subject: Re: How can I use #define to make something completely disappear?
Message-ID: <140@fxgrp.UUCP>
Date: Sat, 31-Oct-87 07:30:44 EST
Article-I.D.: fxgrp.140
Posted: Sat Oct 31 07:30:44 1987
Date-Received: Tue, 3-Nov-87 00:40:43 EST
References: <10083@brl-adm.ARPA>
Reply-To: ljz@fxgrp.UUCP (Lloyd Zusman)
Followup-To: <10083@brl-adm.ARPA> ultra!wayne@ames.arpa (Wayne Hathaway)
Organization: FX Development Group, Inc., Mountain View, CA
Lines: 39

In article <10083@brl-adm.ARPA> ultra!wayne@ames.arpa (Wayne Hathaway) writes:
>
>Anybody got any suggestions? [ about how to conditionally comment out printf]

How 'bout ...

#ifdef DEBUG
# define D(X)	X
#else
# define D(X)
#endif

Then, in your program you can have ...

        D(printf("%s %s %d %d %g\n", foo, bar, baz, furd, farkle));

The double parens are a bit unaesthetic to me, but this gets the job done.

Another variation ...

#ifdef DEBUG
# define dprintf(X)	printf X
#else
# define dprintf(X)
#endif

Then, in your program ...

	dprintf(("%s %s %d %d %g\n", foo, bar, baz, furd, farkle));

More double parens, but it works.

You can get fancy with if statements, testing of debug flags, etc., but I
think you get the idea.

-- 
Lloyd Zusman, Master Byte Software, Los Gatos, California
"We take things well in hand."
...!ames!fxgrp!ljz