There is already a bullet on that topic, see MPI_AINT, MPI_OFFSET Is there an MPI datatype that can be used to send and receive these values? This needed by applications working with MPI windows and files. in section Clarifications (10th item there) on http://www.cs.uiuc.edu/homes/wgropp/projects/parallel/MPI/mpi-errata/ Bill Gropp has proposed to put this topic on the agenda of MPI 2.2. I agree and I'm forwarding your mail therefore to the MPI 2.2 mailing list. On Thu, 24 Jan 2008 10:41:52 -0600 robl_at_[hidden] (Robert Latham) wrote:

I hope this is less contentious than adding 'const' keywords...

I would like to propose a new built-in type MPI_OFFSET, defined to be a type corresponding to INTEGER(KIND=MPI_OFFSET_KIND) or MPI_Offset

This is a minor addition to the standard, which would have no impact on existing code while serving to simplify code which exchanges file offsets among processes.

There is a workaround in the standard: a user can define a type from MPI_BYTE:

MPI_Type_contiguous(sizeof(MPI_Offset), MPI_BYTE, &offtype);

However, it would clearly be more convienient to operate on built-in types.

MPI Datatype: MPI_OFFSET Corresponding C type: long long int Corresponding Fortran type: INTEGER(KIND=MPI_OFFSET_KIND)

Thanks ==rob

-- Rob Latham Mathematics and Computer Science Division A215 0178 EA2D B059 8CDF Argonne National Lab, IL USA B29D F333 664A 4280 315B _______________________________________________ mpi-21 mailing list mpi-21_at_[hidden] http://lists.cs.uiuc.edu/mailman/listinfo/mpi-21

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