[MPI3 Fortran] [Interop-tr] [Mpi-forum] Comment on Fortran WG5 ballot N1846

Rasmussen, Craig E rasmussn at lanl.gov
Tue Apr 19 17:48:02 CDT 2011

Array of buffer arguments (array of pointers to buffer arguments?) would indeed be icky.  But it is not likely that a user is really overlapping communication with computation on all of the buffers involved in the MPI_WAITALL call.  So perhaps one extra overloaded argument for a buffer is OK.  Doesn't change existing practice or codes (can't do that or I'll get in trouble with Rolf again :-)


On Apr 19, 2011, at 4:37 PM, Van Snyder wrote:

> On Tue, 2011-04-19 at 14:53 -0700, Jeff Squyres wrote:
>> 1. The signature of MPI_WAIT (and friends) has been around for 18
>> years and there's lots of codes using it.  It would be fairly
>> disruptive to change it.
>> This may be a weak argument; the other 2 are stronger.
>> 2. The request passed to MPI_WAIT may not have a buffer associated
>> with it.  MPI has lots of types of requests, not just non-blocking
>> point-to-point communication requests.
>> 3. Other flavors of MPI_WAIT take arrays of requests (e.g.,
>> MPI_WAITALL). We'd have to pass an array of buffers corresponding to
>> the array of requests, which would just be plain icky (would you have
>> to have an array of fortran pointers to refer to all the requisite
>> buffers?).
> This is what Fortran generic interfaces, or optional arguments, are for.
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