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Subject: Re: [OMPI users] [Open MPI Announce] Open MPI v1.3.3 released
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2009-07-22 11:20:46

On Jul 20, 2009, at 9:03 AM, Dave Love wrote:

> > Hmmm...there should be messages on both the user and devel lists
> > regarding binary compatibility at the MPI level being promised for
> > 1.3.2 and beyond.
> This is confusing. As I read the quotes below, recompilation is
> necessary, and the announcement has items which suggest at least
> some of
> the ABI has changed.

The MPI ABI has not changed since 1.3.2. We started making MPI ABI
promises with v1.3.2 -- so any version prior to that (including 1.3.0
and 1.3.1) are not guaranteed to be ABI compatible. To be clear: you
should be able to mpicc/mpif77/etc. an MPI application with Open MPI
v1.3.2 and then be able to run it against an Open MPI v1.3.3
installation (e.g., change your LD_LIBRARY_PATH to point to an OMPI
v1.3.3 installation).

Note that our internal API's are *not* guaranteed to be ABI compatible
between releases (we try hard to keep them stable between releases in
a single series, but it doesn't always work). We're only providing an
ABI guarantee for the official MPI API.

> Could the promise also specify that future ABI changes will result in
> ELF version changes to avoid any more of the mess with the 1.2 and 1.3
> libraries wrongly appearing as compatible to the dynamic linker? It
> should just be a question of managing changes and doing the right
> thing
> with libtool.

Yes, we should. This issue has come up before, but it's gotten
muddied by some other (uninteresting) technical issues. I'll bring it
up again with the rest of the developers.

Jeff Squyres