[MPIWG Fortran] BIND(C) attribute of MPI callback functions

[Junchao Zhang]

On Wed, Jul 2, 2014 at 7:05 AM, Bill Long <longb at cray.com> wrote:

>
> On Jul 2, 2014, at 2:11 AM, Rolf Rabenseifner <rabenseifner at hlrs.de>
> wrote:
>
> > Bill,
> >
> > The reason for removal of BIND(C) was simple:
> > Four callbacks contain LOGICAL arguments
> > and we learnt that LOGICAL and BIND(C) does not work together.
> > Therefore the errata is correct.
>
> Agreed.
>
> >
> > I hope you find a solution for storing the callback pointer
> > in a C structure and to bring it back to Fortran.
> > I expect that calling the Fortran callbacks
> > in a portable way may require Fortran code
> > that calls the callback.
>
> For compilers that support the TS, there should be no problem. As noted by
> Junchao, Cray and Gfortran did not have a problem.  The IBM compiler
> appears to have overlooked the TS  change. A bug report to IBM should
> resolve the issue.  The fix is trivial - just disabling an error message
>

Have sent two bug reports regarding F08 to IBM. One is the BIND(C). The
other is that XLF-15.1 does not support storage_size().


> Cheers,
> Bill
>
>
> >
> > Best regards
> > Rolf
> >
> >
> > ----- Original Message -----
> >> From: "Bill Long" <longb at cray.com>
> >> To: "MPI-WG Fortran working group" <mpiwg-fortran at lists.mpi-forum.org>
> >> Sent: Tuesday, July 1, 2014 9:06:05 PM
> >> Subject: Re: [MPIWG Fortran] BIND(C) attribute of MPI callback functions
> >>
> >>
> >> On Jul 1, 2014, at 2:00 PM, Junchao Zhang <jczhang at mcs.anl.gov>
> >> wrote:
> >>
> >>> Hello,
> >>>  Errata for MPI-3.0 removed the BIND(C) attribute of MPI callback
> >>>  functions. But in an implementation, to pass the Fortran
> >>>  procedure to the backend C, I need to get its C function pointer
> >>>  with c_funloc, as the following code shows. When I compile it
> >>>  with IBM XLF 15.1, it complains with such an error "1516-203 (S)
> >>>  The argument to the intrinsic procedure C_FUNLOC must be a
> >>>  procedure with the BIND(C) attribute." In my experiments, gcc
> >>>  and Cray ftn are fine with it.  Looking at
> >>>  https://gcc.gnu.org/onlinedocs/gfortran/C_005fFUNLOC.html, I
> >>>  find c_funloc indeed requires an interoperable function
> >>>  argument. Any comments?
> >>
> >> This requirement on the argument of C_FUNLOC was removed by TS 29113,
> >> subclause 8.1 “Removed restrictions on ISO_C_BINDING module
> >> procedures”.
> >>
> >> Cheers,
> >> Bill
> >>
> >>
> >>
> >>>
> >>> subroutine MPI_Comm_create_errhandler_f08(comm_errhandler_fn,
> >>> errhandler, ierror)
> >>>    use, intrinsic :: iso_c_binding, only : c_funloc, c_int,
> >>>    c_funptr
> >>>    use :: mpi_f08, only : MPI_Errhandler,
> >>>    MPI_Comm_errhandler_function
> >>>    use :: mpi_c_interface, only : c_Errhandler,
> >>>    MPIR_Comm_create_errhandler_c
> >>>
> >>>    implicit none
> >>>
> >>>    procedure(MPI_Comm_errhandler_function) :: comm_errhandler_fn
> >>>    type(MPI_Errhandler), intent(out) :: errhandler
> >>>    integer, optional, intent(out) :: ierror
> >>>
> >>>    type(c_funptr) :: comm_errhandler_fn_c
> >>>
> >>>    comm_errhandler_fn_c = c_funloc(comm_errhandler_fn) !! xlf
> >>>    issues an error
> >>>    ierror_c = MPIR_Comm_create_errhandler_c(comm_errhandler_fn_c,
> >>>    errhandler%MPI_VAL)
> >>>    ...
> >>> end subroutine MPI_Comm_create_errhandler_f08
> >>>
> >>> --Junchao Zhang
> >>> _______________________________________________
> >>> mpiwg-fortran mailing list
> >>> mpiwg-fortran at lists.mpi-forum.org
> >>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> >>
> >> Bill Long
> >>
> longb at cray.com
> >> Fortran Technical Suport  &                                  voice:
> >> 651-605-9024
> >> Bioinformatics Software Development                     fax:
> >> 651-605-9142
> >> Cray Inc./ Cray Plaza, Suite 210/ 380 Jackson St./ St. Paul, MN 55101
> >>
> >>
> >> _______________________________________________
> >> mpiwg-fortran mailing list
> >> mpiwg-fortran at lists.mpi-forum.org
> >> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> >>
> >
> > --
> > Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner at hlrs.de
> > High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530
> > University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832
> > Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner
> > Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room 1.307)
> > _______________________________________________
> > mpiwg-fortran mailing list
> > mpiwg-fortran at lists.mpi-forum.org
> > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
>
> Bill Long
>       longb at cray.com
> Fortran Technical Suport  &                                  voice:
> 651-605-9024
> Bioinformatics Software Development                     fax:  651-605-9142
> Cray Inc./ Cray Plaza, Suite 210/ 380 Jackson St./ St. Paul, MN 55101
>
>
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>
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