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Subject: Re: [OMPI users] Prototypes for Fortran MPI_ commands using 64-bit indexing
From: Dave Love (d.love_at_[hidden])
Date: 2013-12-12 12:03:09


"Jeff Squyres (jsquyres)" <jsquyres_at_[hidden]> writes:

> On Dec 10, 2013, at 10:42 AM, Dave Love <d.love_at_[hidden]> wrote:
>
>> This doesn't seem to have been fixed, and I think it's going to bite
>> here. Is this the right change?
>
> Thanks for reminding us.
>
>> --- openmpi-1.6.5/ompi/config/ompi_setup_mpi_fortran.m4~ 2012-04-03 15:30:24.000000000 +0100
>> +++ openmpi-1.6.5/ompi/config/ompi_setup_mpi_fortran.m4 2013-12-10 12:23:54.232854527 +0000
>> @@ -127,8 +127,8 @@
>> AC_MSG_RESULT([skipped (no Fortran bindings)])
>> else
>> bytes=`expr 4 \* $ac_cv_sizeof_int + $ac_cv_sizeof_size_t`
>> - num_integers=`expr $bytes / $OMPI_SIZEOF_FORTRAN_INTEGER`
>> - sanity=`expr $num_integers \* $OMPI_SIZEOF_FORTRAN_INTEGER`
>> + num_integers=`expr $bytes / $ac_cv_sizeof_int`
>> + sanity=`expr $num_integers \* $ac_cv_sizeof_int`
>
> I think this is right, but it is has different implications for different series:
>
> 1. No more releases are planned for the v1.6 series.

Yes, but I need it for compatibility.

(In case anyone else tries: for some reason I can't rebuild configure
with the autotools on RHEL6, though it has the specified versions or
above; I patched configure directly.)

> We can commit this fix over there, and it will be available via nightly tarballs. There are also ABI implications -- see #2, below.

I'm building rpms with patches anyhow.

> 2. This fix changes the ABI for the 1.5/1.6 and 1.7/1.8 series
> (separately, of course). As such, we will need to make this a
> non-default configure option. E.g., only do this new behavior if
> --enable-abi-breaking-fortran-status-i8-fix is specified (or some name
> like that). By default, we have to keep the ABI for the entire
> 1.5/1.6 and 1.7/1.8 series -- so if you specify this switch, you
> acknowledge that you're breaking ABI for the -i8 case.

OK, but I assumed that was a non-issue since the ABI is broken anyhow in
the case where it changes, as I understand it.

> 3. For the v1.9 series (i.e., currently the SVN trunk), we can make this be the default, and the --enable-abi-breaking... switch will not exist.
>
> Sound ok?

It doesn't matter to me as long as I know the change DTRT, but my OK
probably isn't relevant. Thanks.