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

[Jeff Squyres]

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