Yes, this is worth an ATI - the fact that we traded this much mail on it is proof of that :) Thanks, Jeff. Bill On Apr 17, 2009, at 8:14 AM, Jeff Squyres wrote:

Someone pointed out to me this morning that there's no restriction on the value of EXTRA_STATE when CREATE_KEYVAL is invoked -- it may be an expression, for example. I think that pretty much seals the deal that #2 is the correct way.

I think that this is worth an ATI in the text; does anyone disagree? I volunteer to write it up/make a 3.0 ticket (hey, first ticket for the Misc WG! :-) ) if no one disagrees.

On Apr 17, 2009, at 8:59 AM, Supalov, Alexander wrote:

...

Hi,

Intel MPI (and most likely other MPICH2 derivatives) appears to use method #2.

Best regards.

Alexander

-----Original Message----- From: Jeff Squyres [mailto:jsquyres_at_[hidden]] Sent: Thursday, April 16, 2009 4:19 PM To: MPI 2.2; Rajeev Thakur; William Gropp; Rolf Rabenseifner; Hubert Ritzdorf; Terry Dontje; Dave Goodell; Darius Buntinas; Pavan Balaji; Supalov, Alexander; Bronis de Supinski; David Solt; Hans Westgaard Ry; Håkon Bugge Subject: Another MPI-2.2 attribute ambiguity?

This is related to -- but different from -- MPI 2.2 ticket #55 ("MPI-2.1 Cross-language attribute example is wrong"). Explicitly adding all the #55 CC members to this mail, plus a few others.

I cannot find any text in MPI-2.1 (e.g., p223-225) describing specific behavior regarding the EXTRA_STATE arguments passed to the Fortran keyval copy and delete functions (both the ADDRESS_KIND and deprecated flavors). I see two choices:

1. pass the user's original EXTRA_STATE argument by reference to the callbacks, or 2. copy the user's original EXTRA_STATE into internal MPI storage and pass *that* value by reference to the callbacks

==> Open MPI currently does #1. What do other implementations do?

I raise this issue because the text does not indicate which way is right. And I just ran across an old Sun test that assumed #2. But our internal copy of the Intel MPI tests assume #1 (to be fair: I have no idea if the Intel tests originally assumed #2 and we changed them to #1 over time). Indeed, #2 is actually in-line with the philosophy of storing attribute values in internal MPI storage. E.g.:

INTEGER foo = 4 INTEGER bar CALL MPI_COMM_SET_ATTR(comm, keyval, foo, ierr) foo = 5 CALL MPI_COMM_GET_ATTR(comm, keyval, bar, flag, ierr)

bar should equal 4, not 5 (right?).

So what does that mean (or imply) about the EXTRA_STATE value passed to the Fortran callbacks?

-- Jeff Squyres Cisco Systems

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-- Jeff Squyres Cisco Systems

William Gropp Deputy Director for Research Institute for Advanced Computing Applications and Technologies Paul and Cynthia Saylor Professor of Computer Science University of Illinois Urbana-Champaign