On Nov 12, 2013, at 4:42 AM, George Bosilca <bosi...@icl.utk.edu> wrote:
>> 2. In the 64 bit case, you'll have a difficult time extracting the MPI >> status values from the 8-byte INTEGERs in the status array in Fortran >> (because the first 2 of 3 each really be 2 4-byte integers). > > My understanding is that in Fortran explicitly types variables will retain > their expected size. Thus, instead of declaring > > INTEGER :: status[MPI_STATUS_SIZE] > > one should go for > > INTEGER*4 :: status[MPI_STATUS_SIZE] > > This should make it work right now. You are correct. That's a good workaround. > However, it is a non-standard solution, and we should fix the status handling > internally in Open MPI. > > Looking at the code I think that correctly detecting the type of our > ompi_fortran_integer_t during configure (which should be a breeze if the > correct flags are passed) should solve all issues here as we are protecting > the status conversion between C and Fortran. Not quite. We do already correctly determine ompi_fortran_integer_t as a C "int" or "long long" (that's what I saw yesterday when I tested this myself). 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. Either way, as you say, it's a nonstandard solution. So I don't know which way is "more correct". On the one hand, we've had it this way for *years* (so perhaps there's code out there that uses the George workaround and is working fine). But OTOH, it's different than what you would have to do in the non-dash-i8 case, and so we should make MPI_STATUS_SIZE be 6 and then Fortran code will work identically (without INTEGER*4) regardless of whether you used -i8 or not. Shrug. > Jim, can you go in the include directory on your Open MPI installation and > grep for the definition of ompi_fortran_integer_t please. > > George. > > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
