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From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: comp.lang.c
Subject: Re: C + Make
Message-ID: <27886:Sep1816:48:5990@kramden.acf.nyu.edu>
Date: 18 Sep 90 16:48:59 GMT
References: <0949@sheol.UUCP> <26567@mimsy.umd.edu> <0955@sheol.UUCP>
Organization: IR
Lines: 18

In article <0955@sheol.UUCP> throopw@sheol.UUCP (Wayne Throop) writes:
> Now, "ideally" the construction steps (eg: compilers) and make should
> talk to each other about dependencies.

Exactly. This can be done rather cleanly: cc has a -F flag to output a
list of all files it'll open. Every output file has a dependency list,
consisting of just the commands needed to create that file. make zooms
through the commands, giving each one a -F to find out what files it'll
use. It continues recursively, then invokes real compiles as necessary.
A file is always re-made if its dependency list has changed.

For efficiency, make can cache the -F output in another spot, knowing
that it must reinvoke cc -F whenever any of those files are touched.

If all constructors (including make itself) have a -F flag, this scheme
becomes quite reliable and modular.

---Dan