[MPI3 Fortran] Start discussing new Fortran binding

Lionel, Steve steve.lionel at intel.com
Tue Feb 19 10:32:46 CST 2008

> Jeff and I tried to make this work out in our paper but thought there
> might be problems interfacing with exiting MPI implementations.
> However, I agree this would be a better approach if it can be made to
> work with MPI implementations that work with both integers and
> pointers to structs.  I'll think some more about how to use your
> approach, perhaps you could add you brain power to it as well.
> I think this should be the main topic for conversation in our telecon
> this week.  Agree?

I will admit that I am not steeped in MPI to anywhere near the degree I
am in Fortran.  If you're saying that there are MPI implementations
where the handle is an integer that is NOT also the size of an address,
then that would be tricky and would have to be handled as an
implementation-dependent named constant giving the proper kind value
based on the equivalent C type.  (An irritant is that Fortran KIND
values are implementation-dependent, so what may be kind 4 for one
compiler is kind 3 for another.  But using the values in ISO_C_BINDING
would be the way around that.)

I'll be glad to help as best I can. I agree that this is a fundamental
issue that needs to be resolved before you can get much further.  I
would argue for an opaque type regardless - you can change what's inside
it on a per-implementation basis.

I have not participated in the con calls before, so please point me to
the details when they become available.

Steve Lionel
Developer Products Division
Intel Corporation
Nashua, NH 

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