[Mpi-forum] why is MPI_Status not opaque?

[Jeff Hammond]

I assume that MPI_Status is not opaque because somebody asserted that
function call overhead was too much for some use cases.  Was there more to
it than this?

Why does the standard say there is an opaque part for elements and
cancelled, but not make those visible?  The lack of consistency here
doesn't make a lot of sense to me.

MPI_Status not being opaque was a horrible mistake but I would like to be
less mad about it by learning what possible reasons for it existed in 1995.

Thanks,

Jeff

-- 
Jeff Hammond
jeff.science at gmail.com
http://jeffhammond.github.io/
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