[Mpi-forum] MPI_DATATYPE_NULL when count=0

[Balaji, Pavan]

It is valid.  The buffer and type are significant only when the count is non-zero.

 -- Pavan

Sent from my iPhone

On Jan 13, 2016, at 11:26 AM, Jeff Hammond <jeff.science at gmail.com<mailto:jeff.science at gmail.com>> wrote:

Is it allowed to communicate messages with (buffer=NULL,count=0,type=MPI_DATATYPE_NULL)?

George thinks MPI_DATATYPE_NULL cannot be used even when count=0, which I think is ridiculous, particularly when one makes the analogy to buffer=NULL.

See http://www.open-mpi.org/community/lists/users/2016/01/28255.php for the thread in question.

There is example code in MPI that uses this behavior.  George and I agree that example text is non-normative, but I cannot imagine how this example came to exist without the Forum believing it to be valid.

Jeff

--
Jeff Hammond
jeff.science at gmail.com<mailto:jeff.science at gmail.com>
http://jeffhammond.github.io/
_______________________________________________
mpi-forum mailing list
mpi-forum at lists.mpi-forum.org<mailto:mpi-forum at lists.mpi-forum.org>
http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mpi-forum.org/pipermail/mpi-forum/attachments/20160113/2c77db69/attachment-0001.html>