Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10 5/3/83; site hou5h.UUCP
Path: utzoo!watmath!clyde!cbosgd!ihnp4!houxm!vax135!ariel!hou4b!hou5f!hou5g!hou5h!mgh
From: mgh@hou5h.UUCP (Marcus Hand)
Newsgroups: net.lang.c
Subject: Re: Can #define `token-string' be empty?
Message-ID: <395@hou5h.UUCP>
Date: Mon, 18-Feb-85 18:13:46 EST
Article-I.D.: hou5h.395
Posted: Mon Feb 18 18:13:46 1985
Date-Received: Thu, 21-Feb-85 07:16:58 EST
References: <140@gitpyr.UUCP>
Organization: AT&T Information Systems Laboratories, Holmdel, NJ
Lines: 23

> Is
>	#define x
> valid?

Oh yes, very much so.  It is very useful for controlling conditional
compilation, eg the inclusion or exclusion of debugging and trace code:

	#define	DEBUG
	.
	.
	.
	#ifdef DEBUG
		fprintf(stderr,"Variable is %d\n",Variable);
	#endif

It can also be set on the compilation command line (and inside makefiles
of course) like this:

	cc .... -DDEBUG ....

	Hope this helps,

		marcus hand