Re: 1.5 automatically generating C++, F77 tags

[Alexandre Duret-Lutz]

>>> "Albert" == Albert Chin <address@hidden> writes:

 Albert> On Mon, Jun 02, 2003 at 05:06:42PM -0500, Bob Friesenhahn wrote:
 >> On Mon, 2 Jun 2003, Albert Chin wrote:
 >> 
 >> > It's really annoying to have 1.5 automatically generate the C++ and
 >> > F77 tags. I'm trying to figure out why it does this. We have the
 >> > following in libtool.m4:
 >> >   dnl If AC_PROG_CXX has already been expanded, run AC_LIBTOOL_CXX
 >> >   dnl immediately, otherwise, hook it in at the end of AC_PROG_CXX.
 >> >     AC_PROVIDE_IFELSE([AC_PROG_CXX],
 >> >       [AC_LIBTOOL_CXX],
 >> >       [define([AC_PROG_CXX], defn([AC_PROG_CXX])[AC_LIBTOOL_CXX
 >> >     ])])

[...]

 Albert> I'm trying to do it automatically. I want to run AC_LIBTOOL_CXX *only*
 Albert> if AC_PROG_CXX is called. Can autoconf do this?

Automake setups its dependency tracking code for various
languages with code similar to the above.  Actually, the above
would work if Libtool was not running expanding AC_PROG_CXX
itself! (This happens when AC_LIBTOOL_LANG_CXX_CONFIG is
expanded in _LT_AC_TAGCONFIG.)

As I see it, the only way to achieve what you want would be to
rewrite the `case $tagname' switch from _LT_AC_TAGCONFIG in
plain M4 (instead of shell).  This way you can ensure that
AC_LIBTOOL_LANG_CXX_CONFIG is expanded only if AC_PROG_CXX has
been called first.  Likewise for other languages.  However I
don't think you can do this and still allow AC_PROC_CXX to be
called after AC_PROG_LIBTOOL.

-- 
Alexandre Duret-Lutz