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From: chris@nrcvax.UUCP (Chris Grevstad)
Newsgroups: comp.unix.questions,comp.unix.wizards
Subject: Re: Strange makefile construct
Message-ID: <1171@nrcvax.UUCP>
Date: Sat, 5-Sep-87 22:41:49 EDT
Article-I.D.: nrcvax.1171
Posted: Sat Sep  5 22:41:49 1987
Date-Received: Tue, 8-Sep-87 02:17:42 EDT
References: <1162@nrcvax.UUCP> <781@custom.UUCP>
Reply-To: chris@minnie.UUCP (Chris Grevstad)
Organization: Frobozo Items Co. Inc. Ltd.
Lines: 43
Xref: mnetor comp.unix.questions:3927 comp.unix.wizards:4121

In article <1162@nrcvax.UUCP>, I (Chris Grevstad) write:
> I was looking at some source that came across the net some time ago and
> ran across a very strange construct in the makefile.  It appears that this
> makefile is targeted for a SYSV system and I am familiar only with 4.2BSD
> make.
> 
> This is the weirdness:
> 
> target: file1.o file2.o file3.o file4.o
> 	$(CC) $(CFLAGS) $(?:.o=.c)
> 
> Any suggestions? [....]
> 
> My interpretation says:
> 	This:
> 		$(CC) $(CFLAGS) $(?:.o=.c)
> 	becomes this:
> 		$(CC) $(CFLAGS) file1.c file2.c file3.c file4.c

and boykin@custom.UUCP (Joseph Boykin) responds:
> [agreement as to my interpretation but has a caveat]
> ...
>than the target.  The problem with this particular command is
>that 'target' may now be compiled with only three (or less) files
>instead of all four if one or more of the .o files was not modified;
>given the command, this may cause an error.

Yes, that is true if the target is supposed to be some sort of executable.
In the application that I found this, the target is in fact a library, and
the $(CC) line is followed by a few lines that either create the library
or update the library, whichever is needed.

Guy Harris (I think it was Guy, I have since deleted the mail) also responded
to the latter part of my posting about the 4th generation make by pointing
out something to me that I had forgotten, which is that there is a very good
description of the new make in the proceeedings for the Portland Usenix
conference.

-- 
	Chris Grevstad
	cit-vax!elroy!nrcvax!chris@rutgers.edu
	hplabs!sdcrdcf!psivax!nrcvax!chris
	ihnp4!nrcvax!chris