Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!helios!csseq!randy
From: randy@csseq.cs.tamu.edu (Randy Hutson)
Newsgroups: comp.lang.c
Subject: Re: #define DEBUG... (using printf for debugging)
Message-ID: <5192@helios.TAMU.EDU>
Date: 3 May 90 21:15:43 GMT
References: <11290@hoptoad.uucp> <40628@cornell.UUCP>
Sender: usenet@helios.TAMU.EDU
Followup-To: comp.lang.c
Organization: Computer Science Department, Texas A&M University
Lines: 22


In article <40628@cornell.UUCP> gordon@cs.cornell.edu (Jeffrey  Adam Gordon) wri
tes:

>I want to have a DEBUG flag which controls whether diagnostic printfs
>are executed or not.

I use something like the following:

#ifdef DEBUG
#define DPRINTF printf
#else
#define DPRINTF if(0) printf
#endif

Now there's no need to put an extra set of parentheses about DPRINTF's
arguments.  As for any efficiency concerns, no compiler I regularly
use (gcc, Sequent cc, and sun cc) generates an explicit comparison
to 0.  However, they do leave in the dead code (calls to printf) unless
the optimizer is invoked, so this method could make your executables
larger if your C compiler doesn't have an optimizer which eliminates
dead code.