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Subject: Re: [OMPI devel] MPI ABI on Linux
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2008-09-09 08:23:42

On Sep 9, 2008, at 2:45 AM, Ralf Wildenhues wrote:

>> At the MPI Forum meeting in Dublin, the MPI ABI meeting was... er...
>> shall we say, "spirited." :-) Both the benefits and drawbacks of an
>> MPI ABI are widely contended (it's a surprisingly complex topic).
> it sounds quite daunting.

It is. :-)

>> - If it is ever completed, MPI ABI compliance will be a separate
>> entity
>> from the MPI 2.x and 3.x standards. ABI compliance will be a
>> checkmark
>> for an MPI implementation, but will be unrelated to an
>> implementation's
>> 2.1, 2.2, 3.0, ...etc. compliance.
> How can that be possible? An MPI ABI will have to be versioned in
> the same way that the API is versioned. You can have an ABI version
> for each API version though, I guess.

That is correct. My first statement wasn't entirely correct --
"unrelated" is probably not quite the correct word. Each ABI version
will be tied to a specific API version. What I was trying to say is
that an implementation can be claim to be API compliant, even if it's
not ABI compliant.

> And of course the MPI C++ ABI will require specifying a C++ ABI
> (which, for Windows, means specifying the compiler and possibly its
> major release number used), but this is venturing off into details.

Not just Windows, right?

Ditto for Fortran.

Jeff Squyres
Cisco Systems