Re: VPATH and Makefiles

[David Boyce]

At 07:31 PM 6/22/2004, Paul D. Smith wrote:
> %% Boris Kolpackov <address@hidden> writes:
>   bk> Even -I won't help him/her to do what he/she wants since only included
>   bk> makefiles are searched in -I-directories. What the original poster
>   bk> wanted is to be able to have let's say /tmp/makefile and then
>
>   bk> $ make -I /tmp
>
> Ah, good point; I didn't see that.  Correct, nothing like that will work.
>
> However, you can do this:
>
>     $ export MAKEFILES=/tmp/makefile
>         ...
>     $ make
>
> Not quite the same thing but perhaps it's helpful.

I've often wished for the equivalent of the Ant "-find" feature to be 
implemented in make. This would simply ask make to work its way up toward 
the root looking for a makefile in each intervening directory and stopping 
when one is found. Basically a recursive version of the current 
makefile-finding algorithm. It would allow you to run make in any subdir of 
a large project tree with only a single Makefile at its base (or e.g. a 
Makefile for each of the 'cmd', 'lib', and 'doc' subtrees), thus removing 
one of the ergonomic problems with single-makefile (non-recursive) build 
models. Of course the same thing can be handled with an array of symlinks 
or a wrapper script or whatever but these come with their own costs.

Although the example above uses /tmp for the usual reasons, in real life 
makefiles - like other source files - are liable to be found within the 
current project's tree. And most SW build layouts are organized such that 
searching up makes sense.

It's hard to imagine this hasn't been considered before. If so, was there a 
persuasive argument against it?

-David Boyce