Re: project in multiply directories

[Ralf Corsepius]

On 09/28/2009 05:55 PM, Bob Friesenhahn wrote:
> On Mon, 28 Sep 2009, Alfred M. Szmidt wrote:
>
> > There is an article called "recursive make considered harmful".
IMO, one of the most overrated articles of all times.

> > According to it, you should have just one Makefile.am in top level
> > with all the rules (all libs etc). By this, make can show its
> > strengths best. Often, a Makefile.am "per directory" seems to be
> > used, but for a new project today this should be avoided. It just
> > slows things down and leads to unneeded compiler calls.
> >
> > I'm sorry, but where on earth did you get this terrible information?
> >
> > A Makefile.am per directory is precisly what should be used, it
> > doesn't incure any extra compiler calls. It also makes it easy to
> > build seperate parts of the tree.
>
> The main advantage of a Makefile per directory is that it makes it
> easier to request building seperate parts of the tree.
Right. Exactly this is a huge win in bigger projects.

> Otherwise the
> approach can waste quite a lot of build performance since each sub-make
> must stat(2) all off the files required by the Makefile target as well
> as all of the generated source file dependencies, and there is quite a
> lot of redundant processing (e.g re-linking) which does not need to
> occur. A non-recursive build can help avoid depending on archive
> libraries and "convenience" libraries which often consume quite a bit of
> the build time.
Agreed, ... but the keyword is "can".

> I have taken a number of large Automake-based projects (C and C++) to
> non-recursive builds and have not regretted it.
I did the same and occasionally regret it. It's as in most situations: 
Everything comes at a price and all approaches have their use-cases.

Ralf