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Subject: Re: [OMPI devel] MPI_File_get_size fails for files > 2 GB in Fortran
From: George Bosilca (bosilca_at_[hidden])
Date: 2010-12-20 14:36:21


Nice catch. The sizes are MPI_Offset in C, and therefore we should not cast them as MPI_Fint. I'll take a look, but I doubt it will be before next year. Meanwhile, patches are always welcomed.

  george.

On Dec 20, 2010, at 10:59 , William George wrote:

>
> In Fortran, calls to MPI_File_get_size return a negative value
> when the file is larger that 2GB.
>
> I am using Open MPI 1.4.3 on an x86_64 system. This happens with OpenMPI
> compiled with Intel compilers or GCC, so I don't think it has
> anything to do with the particular compiler in use.
>
> I can fix this by removing the cast to MPI_Fint in
> the function mpi_file_get_size_ in ompi/mpi/f77/file_get_size_f.c.
>
> Changing:
> *size = (MPI_Fint) c_size;
>
> To:
>
> *size = c_size;
>
>
> But my guess is that this is not a proper fix.
>
> There are a few other suspicious casts to MPI_Fint in the f77
> directory too that probably cause similar problems:
>
> $ $ grep \(MPI_Fint\) *.c
> address_f.c: *address = (MPI_Fint) addr;
> file_get_position_f.c: *offset = (MPI_Fint) c_offset;
> file_get_position_shared_f.c: *offset = (MPI_Fint) c_offset;
> file_get_size_f.c: *size = (MPI_Fint) c_size;
> file_get_view_f.c: *disp = (MPI_Fint) c_disp;
> type_extent_f.c: *extent = (MPI_Fint)c_extent;
>
>
> I can also fix this problem by compiling OpenMPI with
> the flag -i8, but promoting all Fortran INTEGERs to 8-bytes
> does not seem correct either.
>
> So - is this a configuration problem, a compile problem.
> a source code bug, or what? Is there an MPI_FOffsetint
> and/or MPI_FAddressint type that should be used
> in these casts?
>
>
> Regards,
> --
> Bill
>
> William L. George
> National Institute of Standards and Technology
> ITL - Applied and Computational Mathematics Division, Stop 8911
> 100 Bureau Drive
> Gaithersburg, MD 20899-8911
>
>
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