Re: [sigc] VPATH build fails if template.macros.m4 is newer than a header file.

[Murray Cumming <murrayc murrayc com>]

On Sat, 2008-03-08 at 17:40 -0800, Daniel Burrows wrote:
> If I untar the latest sigc++ release (2.2.1) and run the following:
> 
> $ touch sigc++/macros/template.macros.m4

Why would you do this?

If you are changing m4 files then you should probably 
a) be using svn so you can send us a patch for whatever it is you are
doing.
b) be using the autogen.sh script, which might enable maintainer mode,
which might enable generation of .h/.cc files. But I'm offline right now
so I can't double-check that.

> $ mkdir builddir
> $ cd builddir
> $ ../configure
> $ make
> 
>   the build will fail like this:
> 
> make[1]: Entering directory `/tmp/libsigc++-2.2.1/builddir'
> Making all in sigc++
> make[2]: Entering directory `/tmp/libsigc++-2.2.1/builddir/sigc++'
> m4   -I ../../sigc++/macros -I macros ../../sigc++/macros/signal.h.m4  > signal.h
> m4   -I ../../sigc++/macros -I macros ../../sigc++/macros/slot.h.m4  > slot.h
> m4   -I ../../sigc++/macros -I macros ../../sigc++/macros/method_slot.h.m4  > method_slot.h
> m4   -I ../../sigc++/macros -I macros ../../sigc++/macros/object_slot.h.m4  > object_slot.h
> m4   -I ../../sigc++/macros -I macros ../../sigc++/macros/class_slot.h.m4  > class_slot.h
> m4   -I ../../sigc++/macros -I macros ../../sigc++/macros/hide.h.m4  > hide.h
> m4   -I ../../sigc++/macros -I macros ../../sigc++/macros/retype.h.m4  > retype.h
> m4   -I ../../sigc++/macros -I macros ../../sigc++/macros/limit_reference.h.m4  > limit_reference.h
> m4   -I ../../sigc++/macros -I macros ../../sigc++/functors/macros/functor_trait.h.m4  > functors/functor_trait.h
> /bin/sh: functors/functor_trait.h: No such file or directory
> 
>   Commenting out the rule that tries to rebuild .h and .cc files seems
> to prevent the build failure; since the files shipped in the .tar.gz are
> presumably correct, I'll do that for now in the Debian package.  I
> don't know what a proper fix looks like: presumably if those files are
> autogenerated they should be produced in the build directory, not the
> source directory, but that probably requires changing more of the build
> system.
> 
>   Are VPATH builds generally supported by libsigc++,

Yes. I don't think that distcheck would work if they were not.

>  or should I look at
> transitioning the Debian packaging away from using VPATH?

Are you patching the m4 file for debian? Why? If you can't send it
upstream, you should probably be patching the .h/.cc files instead.

-- 
Murray Cumming
murrayc murrayc com
www.murrayc.com
www.openismus.com