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<div id="AppleMailSignature">It is valid. The buffer and type are significant only when the count is non-zero.<br>
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<div> -- Pavan</div>
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Sent from my iPhone</div>
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On Jan 13, 2016, at 11:26 AM, Jeff Hammond <<a href="mailto:jeff.science@gmail.com">jeff.science@gmail.com</a>> wrote:<br>
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<div dir="ltr">Is it allowed to communicate messages with (buffer=NULL,count=0,type=MPI_DATATYPE_NULL)?
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<div>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.</div>
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<div>See <a href="http://www.open-mpi.org/community/lists/users/2016/01/28255.php">http://www.open-mpi.org/community/lists/users/2016/01/28255.php</a> for the thread in question.</div>
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<div>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.</div>
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Jeff<br clear="all">
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-- <br>
<div class="gmail_signature">Jeff Hammond<br>
<a href="mailto:jeff.science@gmail.com" target="_blank">jeff.science@gmail.com</a><br>
<a href="http://jeffhammond.github.io/" target="_blank">http://jeffhammond.github.io/</a></div>
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