Newsgroups: comp.parallel.mpi
From: raja@convex.com (Raja Daoud)
Subject: Re: MPI_PROC_NULL and invalid message tags
Organization: Hewlett-Packard Co.; Convex Technology Center
Date: 2 Mar 1996 19:13:48 -0600
Message-ID: <4haroc$6up@tbag.convex.com>

>> My question to the group is:  is the standard ambiguous on this point,
>> or is the behavior of MPI-F incorrect?

>I would argue that you should not get an illegal tag error if you send
>to MPI_PROC_NULL.

Eric, I would argue for the opposite position.  An MPI program has to be
valid first, then we can check for the various special cases within that
context.  Similarly, can we give an invalid datatype for a zero-length
message?  The behaviour after an erroneous call isn't defined (chap. 2).
This can be used to defend this position (giving an invalid argument makes
the program erroneous).

--Raja

-=-
Raja Daoud				Hewlett-Packard Co.
raja@convex.com				Convex Technology Center

