Hi, I think we should answer the following questions to decide whether and how to define the constants: 1. When would a C MPI program call Fortran MPI subprogram? Probably, never. 2. When would a Fortran MPI program call a C MPI subprogram? Sometimes. 3. When would a C++ MPI program call Fortran MPI program? Probably, never. 4. When would a Fortran MPI program call a C++ MPI program? Probably, never. Here, "subprogram" means a part of program that relies on the MPI use or knowledge of MPI datatypes, etc. This may or may not be a direct call into the respective MPI library.
From this, what is needed is to define Fortran datatypes from mpif.h in C mpi.h. The rest does not seem relevant. Even the existing C++ definitions may just reflect C heritage.
Best regards. Alexander -----Original Message----- From: mpi-22-bounces_at_[hidden] [mailto:mpi-22-bounces_at_[hidden]] On Behalf Of Jeff Squyres Sent: Thursday, October 23, 2008 10:13 PM To: MPI 2.2 Subject: [Mpi-22] Should all constants/types be available in all languagebindings? I notice that OMPI, MPICH2, Intel MPI, and HP MPI all do the following: * define Fortran datatypes in mpi.h (e.g., MPI_INTEGER, MPI_DOUBLE) * define Fortran datatypes in the C++ MPI namespace (e.g., MPI::INTEGER, MPI::DOUBLE, etc.) * do *not* define C datatypes in mpif.h (e.g., MPI_INT, MPI_FLOAT, etc.) Why? AFAICT, there is no rule about what constants have to appear in which language bindings. But doesn't that implicitly mean that all constants are supposed to appear in all language bindings? (the argument for having MPI_DOUBLE available in C, for example, is that a C routine may be invoked to send or receive a message containing Fortran data. Similar arguments exist for why you'd want MPI datatypes from other languages available in your language) This is also related to whether the type MPI::Fint should exist or not. I just filed a ticket about these issues (https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/56 ) and marked it as "feedback requested", meaning that I need feedback from the Forum before a proposal can be made. What do people think? -- Jeff Squyres Cisco Systems _______________________________________________ mpi-22 mailing list mpi-22_at_[hidden] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-22 --------------------------------------------------------------------- Intel GmbH Dornacher Strasse 1 85622 Feldkirchen/Muenchen Germany Sitz der Gesellschaft: Feldkirchen bei Muenchen Geschaeftsfuehrer: Douglas Lusk, Peter Gleissner, Hannes Schwaderer Registergericht: Muenchen HRB 47456 Ust.-IdNr. VAT Registration No.: DE129385895 Citibank Frankfurt (BLZ 502 109 00) 600119052 This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.