On Nov 13, 2013, at 21:05 , Jeff Squyres (jsquyres) <jsquy...@cisco.com> wrote:
> On Nov 12, 2013, at 4:25 PM, George Bosilca <bosi...@icl.utk.edu> wrote: > >>> However, the key here is that MPI_STATUS_SIZE is set to be the size of a >>> ***C*** MPI_Status (but expressed in units of Fortran INTEGER size -- so in >>> the sizeof(int)==sizeof(INTEGER)==4 case, MPI_STATUS_SIZE is 6. But in the >>> sizeof(int)==4, sizeof(INTEGER)==8 case, MPI_STATUS_SIZE is 3. >>> >>> That being said, we *could* change this so that MPI_STATUS_SIZE is always >>> 6, and have the C<—>Fortran status routines just do the Right Thing >>> depending on the size/type of ompi_fortran_integer_t. >> >> Indeed. We can have an Fortran MPI_Status (only in the Fortran interface) >> that will be 3 ompi_fortran_integer_t, and alter the translation macros to >> do the right thing (translate from C int to the chosen Fortran int). > > > I'm not sure I understand what you're proposing: what you say sounds like > what we do today: > > - in the sizeof(int)==sizeof(INTEGER)==4 case, everything is the same size, > and nothing special needs to be done Yes for this part. > - in the sizeof(int)==4, sizeof(INTEGER)==8 case, the Fortran status size is > 3, but the C<->Fortran stuff still basically does a memcpy from the C > MPI_Status to the Fortran array (meaning: the C int’s are not upsized to be > fortran INTEGERs). No. The Fortran status must __always__ be 6, because we need enough room to correctly convert the 3 useful variables to Fortran, plus copy the rest of the hidden things.These 6 type will be INTEGER (which will then be different than the C int). The C<->F stuff will do not a memcpy but copy all elements while casting to the correct Fortran type (ompi_fortran_integer_t). The fact that we are talking about 3 integers in the Fortran status might explain the segfault. This number should never be 3 it should be ALWAYS 6 or the function MPI_Status_c2f will clearly overwrite the memory. George. > > -- > Jeff Squyres > jsquy...@cisco.com > For corporate legal information go to: > http://www.cisco.com/web/about/doing_business/legal/cri/ > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
