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

[Jeff Squyres]

On Jan 27, 2009, at 5:35 PM, William Gropp wrote:

> On the last point, the real answer is that since the attributes  
> behave as if they were set by the now deprecated functions, they  
> should themselves be deprecated, since we must not change their  
> behavior.  This is also the source of the int/MPI_Fint issue - there  
> was no MPI_Fint in MPI-1.

Wow, the scope of this ticket keeps expanding.  :-)

I see the following attributes in OMPI's mpi.h:

     /* MPI-1 */
     MPI_TAG_UB,
     MPI_HOST,
     MPI_IO,
     MPI_WTIME_IS_GLOBAL,

     /* MPI-2 */
     MPI_APPNUM,
     MPI_LASTUSEDCODE,
     MPI_UNIVERSE_SIZE,
     MPI_WIN_BASE,
     MPI_WIN_SIZE,
     MPI_WIN_DISP_UNIT,

Excluding MPI_WIN_BASE (which, IIRC, is the only address-sized  
attribute in this list), if we deprecate these names, I assume we'll  
simply replace them with new names that behave as if they were set  
from Fortran MPI_COMM_SET_ATTR.  Specifically, the sizes of the values  
will be such that you have to access them with  
INTEGER(KIND=MPI_ADDRESS_KIND) and (MPI_Aint*).

Is that what you're thinking?  If so, how about s/MPI_/MPI_ATTR_/ in  
all the names (perhaps also creating an alias for MPI_WIN_BASE ->  
MPI_ATTR_WIN_BASE just for symmetry)?  I'm open to suggestions for new  
names.

I'd almost prefer to make that a separate (but related) ticket -- the  
issues in #55 are already quite tangled... (i.e., leave out any  
mention of the predefined attributes from #55 and have a new ticket  
for those issues)  Sound reasonable?


-- 
Jeff Squyres
Cisco Systems