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From: jans@mako.UUCP (Jan Steinman)
Newsgroups: net.lang.c
Subject: Re: Hygiene of #define DIR "/usr/lib/news (CLEAN UP)
Message-ID: <587@mako.UUCP>
Date: Fri, 15-Feb-85 12:52:18 EST
Article-I.D.: mako.587
Posted: Fri Feb 15 12:52:18 1985
Date-Received: Tue, 19-Feb-85 08:38:49 EST
References: <5053@elsie.UUCP>
Reply-To: jans@mako.UUCP (Jan Steinman)
Organization: Tektronix, Wilsonville OR
Lines: 26

In article <5053@elsie.UUCP> ado@elsie.UUCP (Arthur David Olson) writes:
>... a thought-provoking way of doing string catenation...
>
>	#define DIR "/usr/lib/news
>
>and used these defines in lines such as
>
>	system(DIR/batch");
>
Most pre-processors work with whitespace delimited tokens, so the above will
not always work.  However, tokens are not allowed to contain embedded
comments, so this is a more portable way to do the trick:

	system(DIR/**//batch");

I use this technique regularly to produce unique labels for assembly macro
expansion:

	#define MY_MACRO(garbage_in)		\
		.globl my_routine/**/garbage_in	\
	my_routine/**/garbage_in:		\
		...(assembly code)...		\
	/* end define MY_MACRO */
-- 
:::::: Jan Steinman		Box 1000, MS 61-161	(w)503/685-2843 ::::::
:::::: tektronix!tekecs!jans	Wilsonville, OR 97070	(h)503/657-7703 ::::::