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From: jkimble@nostromo.austin.ibm.com (The Programmer Guy)
Newsgroups: comp.lang.c
Subject: Re: #define DEBUG... (using printf for debugging)
Message-ID: <2297@awdprime.UUCP>
Date: 4 May 90 19:48:29 GMT
References: <11290@hoptoad.uucp> <40628@cornell.UUCP> <2294@awdprime.UUCP>
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Reply-To: ibmaus!jkimble@cs.utexas.edu (The Programmer Guy)
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> [quick DEBUG method within programs]


Here's how I usually do it:

#define DEBUG(l, f, s)	if (Debug >= l) fprintf(stderr, f, s)

You will have to have "int Debug;" somewhere, usually as a global.

Now you just change (int)Debug to be whatever you want;  I usually
have a command-line option that allows me to specify it in levels (ala
UUCP).  For example:    program -x9   (Debug will be set to 9, maximum debug)
			program -x5   (Debug will be set to 5, medium debug)
			program -x1   (Debug will be set to 1, minimum debug)

Your DEBUG statements look like so within the program:

	DEBUG(7, "Number of elements within array = %d\n", nmbr);
	DEBUG(5, "Pointer a = |%s|\n", a);
	etc., etc., etc.,

Caveats:

	If you just have an information message and don't want any
	data passed, make sure you do something like this:

	DEBUG(7, "We're in rmdir()...\n", "");

	[note the second set of ""]

The final caveat is that you can only pass one parameter per DEBUG()
statement;  therefore if you have multiple variables to print you're
going to have to use more than one DEBUG statement.  However, I think
this is the cleanest way to handle this sort of stuff.  (But I am sure
we're going to see plenty of other methods coming back from The Net).

Hope this helps!
--Jim Kimble,				Phone: 512/823-4479 (work)
Yet Another IBM Contractor		UUCP: ibmaus!jkimble@cs.utexas.edu
TCP/IP Development, 			RISC System/6000, RT++, RS/6000, etc.
IBM Austin, TX

"ALPO is 99 cents a can.  That's almost SEVEN dog dollars!"