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From: wayne@ames.arpa
Newsgroups: comp.lang.c
Subject: How can I use #define to make something completely disappear?
Message-ID: <10083@brl-adm.ARPA>
Date: Fri, 30-Oct-87 18:00:02 EST
Article-I.D.: brl-adm.10083
Posted: Fri Oct 30 18:00:02 1987
Date-Received: Sun, 1-Nov-87 09:31:45 EST
Sender: news@brl-adm.ARPA
Lines: 46

Time for my dumb question of the month ...

I have the following sequence many times in a piece of code:

        #ifdef DEBUG
            printf("XYZ entry, p1=%x, p2=%x\n", p1, p2);
        #endif DEBUG

Normal old obvious stuff, right?  What I would like to do is replace
all of these sequences with something like:

            DBPRINT("XYZ entry, p1=%x, p2=%x\n", p1, p2);

and then have one instance of something like:

        #ifdef DEBUG
        #define DBPRINT printf
        #else
        #define DBPRINT

But of course that doesn't make it; leaving the compiler with

        ("XYZ entry, p1=%x, p2=%x\n", p1, p2);

won't help anything!  For the above example I could of course say

        #ifdef DEBUG
        #define DBPRINT(a,b,c) printf(a,b,c)
        #else
        #define DBPRINT(a,b,c)

but that only works when there are exactly three arguments, and
obviously printf's can have more or less than that.  Guess I could
define DBPRINT1, DBPRINT2, DBPRINT3, etc., but that sounds less than
aesthetic.

Anybody got any suggestions?  (Sure hope this is another one of those
"Boy, that sure is easy; why are you bothering the net?" type things!)

      Wayne Hathaway                  ultra!wayne@Ames.ARPA
      Ultra Network Technologies
      2140 Bering drive               with a domain server:
      San Jose, CA 95131                 wayne@Ultra.COM
      408-922-0100