All MPI implementors: Implementation of MPI constants in C and Fortran / MPI meeting May 3, 2023 9am CDT discussion

2 May 2023

      Dear implementor of an MPI library,

Based on the discussion today in the MPI forum meeting,
I have the following urgent question to you:

  Did you implement all MPI constants that are described in Annex A.1.1 
    as of type "const int (or unnamed enum)"
  as "C integer constant expression"
    (according to the specification of the C language)?

If yes, then all is okay and the proposed change of the MPI standard in
    https://github.com/mpi-forum/mpi-standard/pull/821/files
will not require any change of your MPI implementation.

If not, then please can you tell which MPI constant(s) MPI_XXX 

- have you implemented in a way that

 - it still can be used in an initialization expression, 
   i.e., in a application statement like
     int x=MPI_XXX;
 - but it cannot be used as a case-label in a switch statement like
     switch(MPI_XXX) {
         case MPI_XXX: printf("XXX\n");
         default: ;
     }
 - and cannot be used as a fixed array length in a declaration like
     float x[MPI_XXX];

- and how implemented you such an MPI constant that this problem arises?

We'll discuss this again tomorrow May 3, 2023 at the beginning 
of the MPI forum meeting. 

See you hopefully at the meeting,
and hopefully reporting that you have no problem with the proposal,

kind regards
Rolf

----- Original Message -----
...
From: "Rolf Rabenseifner" <[email protected]>
To: "Main MPI Forum mailing list" <[email protected]>
Cc: "Puri Bangalore" <[email protected]>, "Claudia Blaas-Schenner" <[email protected]>, "Jeff
Hammond" <[email protected]>
Sent: Tuesday, May 2, 2023 2:04:01 PM
Subject: Re: Informal meeting announcement for the May 2023 meeting of the MPI Forum
...
Der forum memebers, dear Wesley,
please can we add in the agenda after
 Informal Errata Reading  705  Fortran has only compile-time constants   Rolf
an additional slot
 Errata Discussion  657 All C const int (or unnamed enum) as compile-time
 constants   Rolf, Jeff H.
Bestr regards
Rolf
----- Original Message -----
...
From: "Rolf Rabenseifner" <[email protected]>
To: "Main MPI Forum mailing list" <[email protected]>
Cc: "Puri Bangalore" <[email protected]>, "Claudia Blaas-Schenner"
<[email protected]>
Sent: Saturday, April 29, 2023 7:38:00 AM
Subject: Informal meeting announcement for the May 2023 meeting of the MPI Forum
...
Dear forum members,
I would like to make the following announcements for the next MPI Forum Meeting
(May 2-5, 2023):
- informal reading and discussion
   #705 Errata: Fortran has only compile-time constants    Rolf
     Issue https://github.com/mpi-forum/mpi-issues/issues/705
     PR    https://github.com/mpi-forum/mpi-standard/pull/819
     PDF
     https://github.com/mpi-forum/mpi-standard/files/11358444/mpi41-report_Issue7...
This errata should be completely discussed in next (May 2-5, 2023) meeting.
It is then planned to have an final errata reading plus errata vote at next
meeting (July 10-13, 2023).
It is a bug since MPI-2.2 because a problem in C was directly mapped to Fortran.
This mapping was wrong.
In Fortran, there is no distinction between link-time and compile-time
constants.
Best regards
Rolf Rabenseifner
--
Dr. Rolf Rabenseifner . . . . . . . . . .. . . [email protected] .
High Performance Computing Center (HLRS) . . . ++49(0)711/685-65530 .
University of Stuttgart . . . . . . www.hlrs.de/people/rabenseifner .
Nobelstr. 19, 70569 Stuttgart, Germany
-- 
Dr. Rolf Rabenseifner . . . . . . . . . .. . . [email protected] .
High Performance Computing Center (HLRS) . . . ++49(0)711/685-65530 .
University of Stuttgart . . . . . . www.hlrs.de/people/rabenseifner .
Nobelstr. 19, 70569 Stuttgart, Germany

Rolf Rabenseifner

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