Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!att!cbnewsl!moss!jona
From: jona@moss.ATT.COM (Jon M. Allingham)
Newsgroups: comp.sources.d
Subject: Re: Looking for a make version to better support software versions
Summary: nmake will do it
Keywords: nmake
Message-ID: <3613@cbnewsl.ATT.COM>
Date: 12 Jan 90 13:07:06 GMT
References: <1440@jimi.cs.unlv.edu>
Sender: nntp@cbnewsl.ATT.COM
Reply-To: jona@moss.ATT.COM
Followup-To: comp.sources.d
Organization: AT&T Bell Laboratories
Lines: 78

In article <1440@jimi.cs.unlv.edu> jack@jimi.cs.unlv.edu (Jack Alexander) writes:

] 
] Hello:
] 
] I have a need for a make-type program that will allow recompilations
] to be dependent on the changing of compiler definitions (i.e., "-DVERSIONB")
] The problem is that I have many megabytes of code that have to support
] many, many different versions of basically the same program.  Because I
] want to keep the guts of the system the same, whereever a slight
] modification is needed for a particular version, I just make the code
] segment conditional using #ifdef's, #ifndef's, etc.  However, when I change
] a compile variable, I don't want to re-compile every file (some directories may
] have 50 source files each), just the ones that actually reference the variable.
] 
] Has anybody heard of any such program?  Does anybody else need such a program?
] If the need is terrific, I may endeavor to hack it into gnu make.  If I do
] this, I would appreciate any recommendations.
] 
] -- Jack Alexander


AT&T has a new version of make (nmake) that does exactly that sort of
thing. You can set variables in the makefile, specify that certain
source files depend on them and then the "cc" line will put in the
-Dvar=val. It maintains all info in a state file and recompiles the
necessary files when needed. Changing the rule will also cause the
correct files to be recompiled.

It also does auto dependency generation, i.e. it determines
automagically what header files are #included (even does nested
includes) and allows make variables to be specified as "SCAN"
variables, in which case it will scan source files (including #include
files) for use of that symbol and include its value as a -Dvar=val.

It also has full support for viewpathing which is really a must for
large projects. Viewpathing allows you to have a "background (or
`official' node" containing the entire project directory structure and
one or more "development nodes" which contain some piece corresponding
to the official structure. This development node is overlayed on the
official node and any files in it supercede the official stuff. Any
files not found in a development node are take from the official node.

Pretty slick actually.

Makefiles are also preprocessed with cpp and there is a lot of support
for conditionals inside the makefile. Setting command line flags will
change the conditionals. Between getting rid of the explicity
dependencies and adding more power to make, nmake makefiles are
significantly smaller and more powerful than their make counterparts.

It also works on many different machines, the only real requirement is
that the C compiler allow an alternate cpp be used since the standard
cpp's header search rules break viewpathing.

The only problem I can forsee is availability outside AT&T. As I am
only a happy user I really don't know what the status is.

If you are interested in finding out more or in determining
availability contact nmake@mozart.ATT.COM or perhaps
steve@mozart.ATT.COM.

My 2 cents on adding features like this to existing makes:
Some stuff can probably be added without too much grief, but you really
are looking at some fundamental changes in the way make works. I know
that Nmake was entirely new code and not a re-hack of make and it still
is a monster program.

----
Jon M. Allingham	(201)386-3637	AT&T Bell Laboratories (Whippany,NJ)
{clyde}!moss!jona			WH 14D-339

"To those of us with real understanding, dancing is the only pure art form"
-Snoopy 
--
----
Jon M. Allingham	(201)386-3637	AT&T Bell Laboratories (Whippany,NJ)
{clyde}!moss!jona			WH 14D-339