Re: VPATH build...

[Ralf Corsepius]

On Tue, 2007-04-03 at 18:02 -0400, Bob Rossi wrote:
> On Tue, Apr 03, 2007 at 04:00:20PM -0600, Ben Bergen wrote:
> > does anyone know of a variable that is defined during the ./configure
> > run that tells where the top level source directory is.  I have tried
> > $top_srcdir, but this is doesn't seem to be defined until the very
> > end.  I can't use the current directory because I am trying to support
> > out-of-path builds.
> 
> Hi Ben,
> 
> I've run into the same problem, and this is what I do,
> 
>   case $target in
>     *-*-mingw*)
>       abs_top_srcdir=`cd $srcdir; pwd -W`
>       abs_top_builddir=`pwd -W`
>       ;;
>     *)
>       abs_top_srcdir=`cd $srcdir; pwd`
>       abs_top_builddir=`pwd`
>       ;;
>   esac
> 
> It's probably not correct,
It isn't.

You will want to use $build instead of $target

>  but it works.
If the only purpose is to access the toplevel source directory inside of
configure, all this is superfluous. You can simply use $srcdir inside of
configure.ac instead.

If the purpose is to propagate the toplevel directory to files in
subdirs through AC_SUBST, using abs_*dir's render configured build-trees
to be non-relocatable (Consider logging in into the same account from
different nfs-mount-points, say /nfs/<machine>/<account>)

If the purpose is to access files inside of the source-tree from inside
of Makefile.am, there are better ways of doing so (using relative paths,
being composed of $(subdir) and $(top_srcdir))

You are probably using an antiquated autoconf. Modern autoconf's already
support abs_top_srcdir and abs_top_builddir.

Ralf