[Mpi-22] [MPI Forum] #55: MPI-2.1 Cross-language attribute example is wrong

[William Gropp]

Probably the least damaging thing to do now is to make them MPI_Fints  
- this (probably) will have no affect in any current implementation,  
and is consistent with most of the text.

I agree that it would be good to deprecate these values, even if we  
don't replace them in 2.2 .

Bill

On Jan 27, 2009, at 5:08 PM, Jeff Squyres wrote:

> On Jan 27, 2009, at 5:56 PM, William Gropp wrote:
>
>> Eek!  Not for 2.2 !  Maybe a historical advice to users ....
>
> There are two issues:
>
> 1. The current text about the C type for predefined attributes is
> erroneous.
>
> p487:46 through 488-3 says that predefined attributes were set by "a
> Fortran call" (it doesn't say which Fortran call), but then says the
> result in C is of type int.  There is no Fortran attribute call that
> sets an attribute value that is exactly equivalent to a C int.  That's
> why MPI-2 created MPI_Fint, right?
>
> So I think that we must do *something* about this issue.
>
> 2. Deprecating the old attribute names now (as you suggested) is not a
> Bad Thing.  Right now, we have a discontinuity of deprecations: some
> functions are deprecated, but values that are supposedly set by those
> functions are *not* deprecated.  If we deprecate those values now and
> provide replacements, it opens the door in MPI-3 (or later) to
> actually whack them from the spec and only use the new names.
> Specifically: deprecating the old names doesn't mean that we have to
> break user apps for MPI-2.2.
>
> -- 
> Jeff Squyres
> Cisco Systems
>
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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