If you search for the word "should" in the document, it is used all over the place. And it does not mean "maybe" http://dictionary.reference.com/browse/should?s=t Rajeev On Nov 27, 2012, at 8:23 AM, Pavan Balaji wrote:

On 11/27/2012 04:48 AM US Central Time, Jeff Hammond wrote:

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Is it explicitly defined anywhere that "foo has been started" means "MPI_I*foo has been called by the appropriate MPI rank" or "sufficient matching has occurred such that foo can proceed without additional explicit remote activity"? Perhaps this text would be more clear if it were more pedantic in this respect, assuming either of my equivalences are correct.

I think this needs to be clarified -- I always tell people that it needs to be matched (even though the standard says it should have "started" -- what does that mean, if matching has started, but not completed, is it considered "started").

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As for language, while "should" isn't legally enforceable in the same way that "must" or "shall" are, the MPI standard is not a legally binding document and I don't think any MPI implementer wants to be known as the jerk that exploits this loophole to create a formally standard-compliant implementation that screws over users by violating the principle of least surprise in important use cases such as Scott's example.

I have to agree with Scott here -- "must" or "is required to be" is a clearer way to describe it.

-- Pavan

-- Pavan Balaji http://www.mcs.anl.gov/~balaji _______________________________________________ mpi-forum mailing list [email protected] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum