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From: gordon@osiris.cso.uiuc.edu (John Gordon)
Newsgroups: comp.lang.c
Subject: Re: Using a define that hasn't been #defined
Message-ID: <1990Oct3.022132.9245@ux1.cso.uiuc.edu>
Date: 3 Oct 90 02:21:32 GMT
References: <5101@hsv3.UUCP>
Sender: news@ux1.cso.uiuc.edu (News)
Organization: University of Illinois at Urbana
Lines: 20


	In fact, there is a very good way to avoid this kind of error: use the
compiler directives #ifdef and #ifndef.  These check to see if a given 
identifier has or has not been #define'd.

	Example:

	#ifdef MSDOS
	do_dos_specific_stuff();
	...
	...

	Hope it helps.


---
John Gordon
Internet: gordon@osiris.cso.uiuc.edu        #include <disclaimer.h>
          gordon@cerl.cecer.army.mil       #include <clever_saying.h>
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