On Apr 14 2011, Ralph Castain wrote:
... It's hopeless, and whatever you do will be wrong for many
people. ...
I think that sums it up pretty well. :-)
It does seem a little strange that the scenario you describe somewhat
implies that one process is calling MPI_Finalize loooong before the
others do. Specifically, the user is concerned with tying up resources
after one process has called Finalize -- which implies that the others
may continue on for a while. It's not invalid, of course, but it is a
little unusual.
I'm finding it more common than we thought. Note that I didn't say that
one process called MPI_Finalize before the others. In this case, they
call it fairly close together, but the individual processes continue
running for quite some time, or until they determine that something is
wrong and exit with non-zero status.
Nobody is denying that it is common. Now, what happens when you encounter
a language or compiler that uses return codes for mere warnings (e.g.
ignored IEEE 754 flags, as stated to be desirable by LIA-1)? Bang!
Remember that C is not the universe and many languages use MPI via the
C interface, but do not let C control their model.
Regards,
Nick Maclaren.
