Re: msys : convert datadir to windows directory syntax

[Vincent Torri]

On Tue, 4 Sep 2007, Keith MARSHALL wrote:
> Vincent Torri wrote, quoting me:
> > > Yes.  You can use the MSYS_AC_CANONICAL_PATH macro, published some time
> > > ago on the MinGW/MSYS lists:
> > > http://article.gmane.org/gmane.comp.gnu.mingw.msys/2785
> >
> > I have a problem with that macro. First note, that I am using autoconf
> > 2.61.
> >
> > Here is how I use that macro:
> >
> > in configure.ac:
> >
> > efreet_datadir=$datadir
> > case "$host_os" in
> >     mingw|mingw32)
> >        MSYS_AC_CANONICAL_PATH([efreet_datadir], [$datadir])
> >     ;;
> > esac
> > AC_SUBST(efreet_datadir)
>
> You could just as well replace all the above with:
>
>  MSYS_AC_CANONICAL_PATH([efreet_datadir],["/default/posix/datadir/path"])
>  AC_SUBST([efreet_datadir])

ok

> > But in the created Makefile, the value of efreet_datadir is:
> >
> > efreet_datadir =
> > D:/msys/1.0/home/vincent/tmp/e17/libs/efreet/${datarootdir}
> >
> > do you know why ?
>
> Yes.  Unless the user assigns it explicitly, on the `configure' command
> line, the value of `$datadir' is unknown when the configure script is run;
> it doesn't become fully defined until you invoke `make'.
>
> In general, you shouldn't use `$datadir' in this way, within a configure
> script; in autoconf-2.60 and later, its default definition is:
>
>  datadir='${datarootdir}'
>  datarootdir='${prefix}/share'
>
> while in earlier versions of autoconf, it is simply:
>
>  datadir='${prefix}/share'
>
> both of which, ultimately, resolve to the same default value in `make',
> if you use the convenional substitutions within `Makefile.in'.

I use datadir (actually efreet_datadir) in AM_CPPFLAGS:

AM_CPPFLAGS=-DPACKAGE_DATA_DIR=\"$(efreet_datadir)\"

is there another solution, with my use fo efreet_datadir ?

> You should also note that even the value of `$prefix' is not known when the
> configure script is run, (again, unless the user has overridden the default
> value).  This can make life difficult, when you want to manipulate paths
> based on the default values of `${prefix}', `${datarootdir}' and friends,
> especially since the actual default values for these are undocumented.
>
> If you are prepared to work with undocumented features, you could achieve
> your apparent goal using something like (untested):
>
>  AC_SUBST([msys_default_prefix], ["$prefix"])
>  test "x$prefix" = xNONE && msys_default_prefix=$ac_default_prefix
>  MSYS_CANONICAL_PATH([msys_default_prefix], ["$msys_default_prefix"])
>  AC_SUBST([efreet_datadir], ['${msys_default_prefix}/share'])
>
> but do be aware that this may break, in some future release of autoconf.

it's bad that is I use that code, it might break later :/

thanks for the help

Vincent