Re: [Mesa3d-dev] libtool (was CVS and SSE)

[Sven M. H. <pe...@gm...>]

On Mon, May 21, 2001 at 09:51:10PM +0200, Marcelo E. Magallon wrote:
>  > > - Set a libtool -version-info of 0:MESA_VERSION:0 where
>  > >   MESA_VERSION would be 30500 for Mesa 3.5.0.
>  > > - On Linux (for ABI-conformance), use an install-hook to create two
>  > >   symbolic links: libGL.so.1 to libGL.so.0.MESA_VERSION.0 and
>  > >   libGL.so to libGL.so.1.
> 
>  I missed Sven's post.  Please don't do this.  It breaks binary
>  compatibility.  On Linux, among others, the soname would end up being
>  libGL.so.0, which means programs compiled with this version of libGL
>  would require a libGL.so.0 in order to run.  The symbolic links only
>  solve the other problem (compiled with libGL.so.1 and run with
>  libGL.so.0 present).  Fixing this once when the library was called
>  libMesaGL.so.3 was painful enough...

Right. Temporarily forgot about the SONAME.


>  > IMHO, libtool should have an option to support arbitrary version numbers.
> 
>  It has.  Please don't use it, it's a headache. (-release-info).  The

It must only do in some brand-new version. 1.4 doesn't seem to know
-release-info.


>  problem libtool solves doesn't exist in the case of a GL library,
>  namely, how do you ensure you aren't breaking binary compatibility on a
>  given plataform?  Some dynamic linkers have the concept of library
>  versions, some don't.  And those that have it, don't share it with the
>  other (not always, at least).  When you use libtool, you place your
>  library's versioning in libtool's hands.  Those who try to change
>  libtool's idea of "correct versioning" get burned (the lucky ones end
>  up with libfoo-1.2.so as library names, the really lucky ones get away
>  with it only because the library already has an stable API).  libtool
>  solves another problem, namely, how do you compile a library on system
>  X with compiler Y?  At this, libtool does a superb job.  But by design,
>  the two solutions are coupled.

This is really a nightmare. How can we have libtool solve the problem of
portable linking for us while still controlling the name of the resulting
library. Anyhow, if other linkers have such different ways of doing things,
how are we supposed to know the correct file name anyhow??


-Sven

-- 
"Would the All-Seeing Eye please look in my direction?"
 [ KeyID........: 0xC297FEAB ]
 [ Fingerprint..: FEA5 0F93 7320 3F39 66A5  AED3 073F 2D5F C297 FEAB ]