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<meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">I honestly can’t remember why we restricted MPI_STATUS_SIZE to Fortran - my best guess is one Jeff mentions, that we were maintaining the possibility that the C and Fortran statues could be a different size, and the possible confusion with sizeof(MPI_Status) is real. I’d go with a distinct name that included FORTRAN as an alternative.<div class=""><br class=""></div><div class="">Bill</div><div class=""><br class=""><div class="">
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<div><br class=""><blockquote type="cite" class=""><div class="">On Sep 8, 2020, at 8:32 AM, Jeff Squyres (jsquyres) via mpiwg-fortran <<a href="mailto:mpiwg-fortran@lists.mpi-forum.org" class="">mpiwg-fortran@lists.mpi-forum.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">Question: why is MPI_STATUS_SIZE only defined in Fortran?<br class=""><br class="">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?<br class=""><br class="">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.<br class=""><br class="">To be totally clear, you can't do this in C:<br class=""><br class=""> MPI_Fint f_status[MPI_STATUS_SIZE];<br class=""><br class="">Is this an oversight? Shouldn't we define MPI_STATUS_SIZE in all languages?<br class=""><br class="">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))?<br class=""><br class="">Thoughts?<br class=""><br class="">If we view this as an errata, I think there's still time to get an update in for MPI-4.<br class=""><br class="">-- <br class="">Jeff Squyres<br class=""><a href="mailto:jsquyres@cisco.com" class="">jsquyres@cisco.com</a><br class=""><br class="">_______________________________________________<br class="">mpiwg-fortran mailing list<br class="">mpiwg-fortran@lists.mpi-forum.org<br class="">https://lists.mpi-forum.org/mailman/listinfo/mpiwg-fortran<br class=""></div></div></blockquote></div><br class=""></div></body></html>