[MPI3 Fortran] Straw vote on integers kinds

[Malcolm Cohen]

Hi Aleks,

> On Wednesday 16 September 2009, Malcolm Cohen wrote:
>> I don't see the option I prefer, viz all interfaces to be generic and
>> not specific.
> Just to clarify for me here. The generic interface seems to me to mean
> nothing unless you specify exactly what it must include as specifics.
> It can of course include a lot more if it wishes. But what is the
> minimum. One specific that accepts MPI_INT_KIND (which is likely to be
> C_INT, I gather?) for *all* integer arguments other than counts, and,
> if different, at least one specific where *all* arguments are are
> default integers.
> Right?

Yes, that is what I had in mind, with explicit permission for the vendor to 
include other specific variations.

In practice, I'd expect the vendor to provide one specific with 32-bit non-count 
integer arguments and one with 64-bit non-count integer arguments.  As you say, 
that way only one module is needed and the right wrapper (or none if it can be 
done directly) will be called whether the user did -i8 or not.  If MPI_INT_KIND 
is 32 bits, then in the 32-bit environment the 64-bit specific is "extra" (i.e. 
not required by MPI) and in the 64-bit environment both are required by MPI. 
And vice versa if MPI_INT_KIND is 64 bits.

I think that would cover all "normal" users with a minimum of fuss, the only 
people it wouldn't cover would be those who wanted a random splattering of 
8/16/32/64 arguments combined, and as far as I'm concerned those people can 
write the explicit INT calls.

Cheers,
-- 
......................Malcolm Cohen, Nihon NAG, Tokyo.