[MPIWG Fortran] MPI-3 ticket 349: Fortran question

[Bill Long]

On 12/13/13 11:15 AM, Craig Rasmussen wrote:
> Hum,
>
> I thought I had sent this out earlier, but just found it in my "outbox".
>
> On Dec 11, 2013, at 9:27 AM, Jeff Squyres (jsquyres) wrote:
>
>> This ticket got a formal reading today at the Forum:
>>
>>     http://svn.mpi-forum.org/trac/mpi-forum-web/ticket/349
>>     (as of this writing, there's still a BIND(C) in there, but it will be removed shortly)
>>
>> The function is basically intended to perform a mathematical operation.  As such, I think that the 2 Fortran bindings should be FUNCTIONs, not SUBROUTINEs (a la MPI_WTICK/MPI_WTIME).
>>
>> Do you agree?  If so, the ticket author (Jim Dinan) is amenable to changing the Fortran bindings to the following (and I'm assuming I have the syntax below correct, but feel free to correct me if they're wrong):
>>
>> -----
>> INTEGER(KIND=MPI_ADDRESS_KIND) MPI_Aint_add(base, disp)
>>     INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) ::  base, disp
>>
>> INTEGER(KIND=MPI_ADDRESS_KIND) MPI_AINT_ADD(BASE, DISP)
>>     INTEGER(KIND=MPI_ADDRESS_KIND) BASE, DISP
>> -----
>>
>
>
> They look ok for me.  I wonder why there are two?  I don't think there should be.
>
> I also think this would be an ideal place to use BIND(C).  I know we had to drop BIND(C) from the official interfaces (not from within an implementation) for a number of reasons, but I think BIND(C) is a good choice for NEW routines.  This will allow purely Fortran stuff to fade into the background.
>

I do not think BIND(C) is a good idea here.  On of the arguments in 
getting rid of BIND(C) was the ambiguity caused by specifying default 
INTEGER for arguments.

BIND(C) makes sense for Fortran routines where the intent is that the 
Fortran implementation is the ONLY implementation and the C users end up 
calling this routine.  This is right for routines that do conversions 
that involve Fortran types.  Until we finally throw off the yoke of 
default INTEGER in the interfaces, that is about the limit of the 
usefulness of BIND(C) on procedures in MPI.

Cheers,
Bill



> -craig
>
>
>
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-- 
Bill Long                                           longb at cray.com
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