Re: [automake] Dependency question with _LDADD

[Peter Johansson]

Michel Briand wrote:
> > > > > Hi all,
> > > > >
> > > > > I implemented a new idea for program's version.
> > > > >
> > > > > In src/bin/Makefile.am:
> > > > >
> > > > > internal_version.c: ${top_srcdir}/PROGRAM_VERSION
> > > > >         ${top_srcdir}/vtempl.pl $(component) $(VERSION) < $(templ) > $@
> > > > >
> > > > > training_SOURCES = training.c internal_version.c
> > > > >
> > > > > The vtempl.pl Perl program takes a template as input and filter it to
> > > > > produce the internal_version.c source file.
> > > > >
> > > > > Each time the PROGRAM_VERSION file will be changed, the new source file
> > > > > will be regenerated, then the build system will recompile it, and
> > > > > relink the program.
> > > > >   
> > > > >           
[...]
> > > > >       
> > > > >           
> > > > Also, what is the reason you don't want to use config.h?
> > > >
> > > >     
> > > >         
> > > Other source files in the project should not be affected by a change of
> > > the VERSION.
> > >
> > > A simple use case when you have you're projet in configuration
> > > management.
> > >
> > > a) You prepare the version 2.1 of the project (you have "2.1pre9" in the
> > > file PROJECT_VERSION). You finish you're work (code, build, test, ...)
> > > and commit.
> > >
> > > b) The integration step comes in, and extract your 2.1pre9 source,
> > > build it, and test it.... With numerous tools that will check static or
> > > dynamic states of the program...
> > >
> > > c) Integration step finishes well and we are ok to release. But we'll
> > > keep the generated files (object, executable) in configuration. So we
> > > don't want to rebuild the tree after all tests have passed. So we do
> > > not want to change the PROGRAM_VERSION if we know that it'll change
> > > config.h => rebuilt the tree...
> > >
> > > The main point here is that we have tests that run a lot of time. And
> > > that we can change the PROGRAM_VERSION according to the configuration
> > > management or the release policy. It's not in the source dependency
> > > field ;).
> > >
> > > Anyway we want the program to be dependant of the version since it's
> > > embedded. So I've a dependency to relink it.
> > >
> > > Is my explanation enough clear/detailed ?
> > >   
> > >       
> > Ok. Got your point. One question though. Where do you read the file 
> > PROGRAM_VERSION?
> >
> > Is the info in PROGRAM_VERSION somehow propagated through variable 
> > $(VERSION)? But I thought $(VERSION) always was set in AC_INIT?
> >
> >     
>
> VERSION defined by configure in config.h will be the package's version
> (as a whole).
> I'll not use it ;).
>   
Ok, now you really confused me. Your Makefile.am looked like:

internal_version.c: ${top_srcdir}/PROGRAM_VERSION
        ${top_srcdir}/vtempl.pl $(component) $(VERSION) < $(templ) > $@

but you meant $(PROGRAM_VERSION), right? What I wanna get to, is that it looks 
like you set the variable for the program version at configure time. If (!) 
that is true, it implies you need to run configure every time you change file 
`PROGRAM_VERSION'. That is no problem, but since you seem to be eager to avoid 
such dependencies you could avoid that by reading the file at make time 
instead. Something like this:

internal_version.c: ${top_srcdir}/PROGRAM_VERSION ${top_srcdir}/vtempl.sh 
Makefile.am $(templ)
        program_version=`echo ${top_srcdir}/PROGRAM_VERSION` && \
        ${top_srcdir}/vtempl.sh $(component) $$program_version < $(templ) > $@


Cheers,
Peter