[Mpi-22] [Mpi-forum] MPI 2.2 proposal: resolving MPI_Request_free issues

[Greg Lindahl]

On Thu, Jul 17, 2008 at 03:46:59PM -0400, Richard Treumann wrote:
> Sorry - the discussion is in the context of MPI_REQUEST_FREE.
> 
> MPI_ISEND(question_buffer .....    request)
> MPI_REQUEST_FREE(request)
> MPI_RECV( reply_buffer)
> free(question_buffer)

Perhaps an implementer would dodge this bullet by having
MPI_REQUEST_FREE do a MPI_CANCEL before freeing anything? That's
assuming you have MPI_CANCEL on a send do the right thing.

Thus, we turn this new can of worms into an existing can of
worms. Voila!

The example above strikes me as being undefined behavior in any case.
I don't think we would guarantee that the message got out at all, and
even if the remote side thinks the message is complete, that doesn't
mean that the sender agrees the message is complete, without calling
WAIT.

-- greg