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From: guy@rlgvax.UUCP (Guy Harris)
Newsgroups: net.unix,net.sources
Subject: Re: file include follower - "cpp" does nicely
Message-ID: <1962@rlgvax.UUCP>
Date: Wed, 30-May-84 01:27:45 EDT
Article-I.D.: rlgvax.1962
Posted: Wed May 30 01:27:45 1984
Date-Received: Fri, 1-Jun-84 08:37:09 EDT
References: <855@ulysses.UUCP>
Organization: CCI Office Systems Group, Reston, VA
Lines: 14

A Makefile generator (the most common use of an include follower) was
posted to "net.sources" by somebody a while ago.  It used "cpp" to follow the
include files - this has the advantage that it even understands "ifdef"s and the
like.  An example of this advantage, which crops up here a fair bit, is
Makefiles for programs which provide a full-screen user interface.  Such
programs need an "#ifdef" for the V7/BSD tty driver vs. the USG tty driver;
depending on the define, it will include <sgtty.h> or <termio.h>.

That Makefile generator was one of the cleverer uses of "cpp" I've seen -
all you do is "cc -E" the source and grab "# <linenum> <filename>" lines
as they go by.

	Guy Harris
	{seismo,ihnp4,allegra}!rlgvax!guy