Re: Non-recursive automake and double-colon rules

[Nick Bowler]

On 2013-03-24 11:33 +0000, Roger Leigh wrote:
> If you switch to non-recursive make (i.e. no use of SUBDIRS),
> but you want to use "include" to retain Makefile.ams in
> subdirectories, you end up running into problems when you
> have multiple copies of -local and -hook rules.
[...]
> I've used GNU make double-colon rules to allow the same target to be
> used multiple times.  While this is GNU make-specific, it's a simple
> and effective way to convert an existing recursive automake setup to
> being nonrecursive.  Possibly worth putting in the documentation (along
> with a portability caveat?)
> 
> I'd be interested to know what other people's experiences have been
> here.  While I could move everything into the top-level Makefile.am,
> keeping rules together with the files they operate on does have some
> advantages.

The way I normally handle this is to not add commands directly to the
-hook or -local rules, but instead to create new rules with commands and
list them as prerequisites to the appropriate -hook or -local rules.
This does not depend on GNU make.  For example:

  all-local: extra-stuff
  extra-stuff:
        echo "hello"

Looking at the GNU make manual, it looks like double-colon rules have an
ordering to them; the above approach does not (and, in fact, allows
the different rules to be run in parallel).  So it may also be necessary
to add prerequisites between the individual rules-with-commands as well.

Cheers,
-- 
Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/)