Everybody wishing to have a serious opinion on ISO Fortran 77 should read the following:

https://stevelionel.com/drfortran/2020/05/16/doctor-fortran-in-military-strength/

Also, Squyres is right about everything, as usual.

Jeff

On Wed, Jan 27, 2021 at 7:09 AM Jeff Squyres (jsquyres) via discuss <discuss@mpich.org> wrote:
On Jan 27, 2021, at 9:45 AM, Raffenetti, Kenneth J. via discuss <discuss@mpich.org> wrote:
>
> The MPICH team is asking if it would be OK to drop support for building MPICH with an F77 only compiler.

MPI -- MPICH, Open MPI, etc. -- has never been able to be built with a F77-only compiler because the MPI standard has never adhered to the Fortran 77 standard.

Additionally, MPI-3.1 17.1.1 quite clearly states that a conformant MPI-3.1 implementation must support either the mpi_f08 module (which implies support for much of the Fortran'08 standard) and/or mpif.h + the mpi module (which requires elements of the Fortran 90 standard).  This requirement has been there since MPI-3.0, published in 2012.

Hence, it has not been possible to build any conformant MPI implementation with a "F77-only" compiler for nearly a decade.

And let's not forget that Fortran 77 limits symbols -- variables, subroutines, and functions -- to 6 characters.  Hence, it has *never* been possible to build any MPI implementation or application with a Fortran 77-only compiler.

Håkon's answer earlier in the thread was also quite correct: "fixed form Fortran" is not the same thing as "Fortran 77".  Please stop conflating the two.

> MPICH will still support all standard Fortran language bindings: mpif.h, use mpi, and use mpi_f08. Does the code you speak of not build with modern Fortran compilers? If so, that is the kind of feedback we are looking for.

That is a good question, much better formed than the original.  It's a question that the entire MPI Forum would benefit hearing answers to!

--
Jeff Squyres
jsquyres@cisco.com

_______________________________________________
discuss mailing list     discuss@mpich.org
To manage subscription options or unsubscribe:
https://lists.mpich.org/mailman/listinfo/discuss
--
Jeff Hammond
jeff.science@gmail.com
http://jeffhammond.github.io/