[mpich-discuss] Is it okay to remove F77 support?

Gus Correa gus at ldeo.columbia.edu
Wed Jan 27 21:26:57 CST 2021

Oh Mr. Hammond, you guys are just die-hards, insisting to defend what you
just did,
namely alarm your community of users with your terribly phrased question.

The original question, at the very subject line of the email,
was very poorly formulated, and suggested the end of mpi.f and such,
which are essential in code written in all sorts of
Fortran-77 code (and various F77 extensions) that abound
among your users.
Don't you care about these users (us)?

Being pedantic, belittling your users alarm after your horrible question,
or berating your users knowledge of what is and what is not strict F77 ISO
doesn't help at all.
After all, we, your users, in one way or another,
as taxpayers and in other ways,
support the development of publicly available high quality
software in national labs, such as mpich, expecting that it will
be useful and usable, and work together (not against) the codes we have.
So presumably we  deserve a little better.

The bad question triggered a whole discussion,
which subsequent answers showed to be a discussion about nothing.

Jeff Squyres pointed out that it was never possible to build
MPI with a compiler strictly adherent to Fortran-77 ISO standard.

So, why, as the initial question asked, do you need to remove
support for something that never existed to begin with?
Why do you need to ask this non-question to the community,
and raise the false alarm?

Indeed, I never paid much attention to that,
but admittedly I have been compiling OpenMPI, MPICH and MVAPICH
all with F90 compilers (gfortran, pgfortran, ifort), although often
times using their Fortran-77 versions (with extensions to the ISO standard
I suppose),
to compile code that depends on
Many of those codes do depend on mpi.f, won't work with F90 modules (or
'use mpi').
I guess this is not unique at all, and a lot of the code base out there,
in various areas of knowledge, works this way.
The original question clearly suggested suppressing this possibility.

Gus Correa

On Wed, Jan 27, 2021 at 12:16 PM Jeff Hammond <jeff.science at gmail.com>

> Squyres' point is that there is not and has never been an MPI Fortran 77
> API and every time someone implies there is, it confuses people.  mpif.h
> requires ISO Fortran 90 - it just happens to support fixed-source form and
> does not require any of the Fortran 90 features that were not ubiquitous in
> compilers ~15 years ago.
> The original question was correct, but could not be interpreted correctly
> by most people.  It asked whether MPICH could drop support for compilers
> that support no Fortran dialect beyond Fortran 77.  The only compiler I
> have ever used that would be impacted by this is g77, which I used in the
> same era that I used Itanium.
> Jeff
>> Well, then the question was very poorly formulated.
>> It suggests suppressing the Mpich Fortran-77 API.
>> Hard to gauge the impact of removing support of F77 compiler (ONLY),
>> but it may cause trouble when building complex code,
>> and linking it to MPI (mpich),
>> as some may actually require a compiler that is specific for Fortran-77,
>> or have Makefiles and other utilities that rely on such a compiler.
>> Gus Correa
>> _______________________________________________
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> --
> Jeff Hammond
> jeff.science at gmail.com
> http://jeffhammond.github.io/
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