Question: why is MPI_STATUS_SIZE only defined in Fortran?
MPI-3.1:2.5.4 p15:36 specifically states that MPI_STATUS_SIZE is only defined in Fortran. Why isn't is also defined in C?
I ask because I was just writing a test for the MPI_Status conversion functions in Open MPI. The test spans both Fortran and C. But in order to test the MPI_Status_f2c / MPI_Status_c2f functions (which are only defined in C, mind you), I wanted to make a stack-allocated array of MPI_Fint's for the INTEGER-array-style Fortran status. ...but I couldn't, because MPI_STATUS_SIZE isn't defined in C. Indeed, there's no mechanism in C for knowing how long an INTEGER-style Fortran status array needs to be -- even though we have functions in C for dealing with INTEGER-style Fortran statuses.
To be totally clear, you can't do this in C:
MPI_Fint f_status[MPI_STATUS_SIZE];
Is this an oversight? Shouldn't we define MPI_STATUS_SIZE in all languages?
Or, perhaps if there's possible confusion between MPI_STATUS_SIZE in C and sizeof(MPI_Status) (since they could actually be different values), perhaps we could call it MPI_FORTRAN_STATUS_SIZE in C? (Or even MPI_FORTRAN_INTEGER_STATUS_SIZE to differentiate it from sizeof(TYPE(MPI_Status))?
Thoughts?
If we view this as an errata, I think there's still time to get an update in for MPI-4.
--
Jeff Squyres
jsquyres@cisco.com_______________________________________________
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