[asterisk-dev] [svn-commits] rizzo: trunk r72700 - /trunk/main/Makefile
rizzo at icir.org
Fri Jun 29 16:12:02 CDT 2007
On Fri, Jun 29, 2007 at 03:49:58PM -0500, Russell Bryant wrote:
> SVN commits to the Digium repositories wrote:
> > Author: rizzo
> > Date: Fri Jun 29 15:33:35 2007
> > New Revision: 72700
> > URL: http://svn.digium.com/view/asterisk?view=rev&rev=72700
> > Log:
> > Make sure that we properly recurse in subdirectories to
> > check dependencies for libraries.
> > Because these targets (e.g. minimime/libmmime.a) are real ones,
> > declaring them .PHONY would cause them to be rebuilt every time
> > (see e.g. SVN 64355).
> > As a workaround I am using the following CHECK_SUBDIR target:
> > CHECK_SUBDIR: # do nothing, just make sure that we recurse in the subdir/
> > minimime/libmmime.a: CHECK_SUBDIR
> > @cd minimime && $(MAKE) libmmime.a
> > which seems to do a better job than .PHONY (probably because
> > .PHONY forces the rebuild even if the recursive make does not think
> > it is necessary).
> Hm, this is interesting. I have always thought that declaring a target
> as .PHONY did the exact same thing as what this method does. In fact,
> the GNU make manual claims they do the same thing.
I think the last sentence in the above manpage is wrong and the two things
are actually different (in fact, if you try, they do behave differently
if the target is a real file). If you read the .PHONY page
it says that .PHONY targets should not be real files, and i bet that internally
gmake uses this assumption to imply that the target is not just _possibly_ out
of date, but it _must_ be rebuilt.
Anyways, FORCE might be a better name than CHECK_SUBDIR for the fake target.
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