MPI_File_get_type_extent(3)        Open MPI        MPI_File_get_type_extent(3)



NAME
       MPI_File_get_type_extent - Returns the extent of the data type in a
       file.


SYNTAX
       C Syntax
           #include <mpi.h>
           int MPI_File_get_type_extent(MPI_File fh, MPI_Datatype
                  datatype, MPI_Aint *extent)

       Fortran Syntax (see FORTRAN 77 NOTES)
           INCLUDE 'mpif.h'
           MPI_FILE_GET_TYPE_EXTENT(FH, DATATYPE, EXTENT,  IERROR)
                 INTEGER   FH, DATATYPE, IERROR
                 INTEGER(KIND=MPI_ADDRESS_KIND) EXTENT


C++ Syntax
       #include <mpi.h>
       MPI::Aint MPI::File::Get_type_extent(const MPI::Datatype&
            datatype) const


INPUT PARAMETERS
       fh        File handle (handle).

       datatype  Data type (handle).



OUTPUT PARAMETERS
       extent    Data type extent (integer).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPI_File_get_type_extent can be used to calculate extent for datatype
       in the file. The extent is the same for all processes accessing the
       file associated with fh. If the current view uses a user-defined data
       representation, MPI_File_get_type_extent uses the dtype_file_extent_fn
       callback to calculate the extent.


FORTRAN 77 NOTES
       The MPI standard prescribes portable Fortran syntax for the EXTENT
       argument only for Fortran 90. FORTRAN 77 users may use the non-portable
       syntax

            INTEGER*MPI_ADDRESS_KIND EXTENT

       where MPI_ADDRESS_KIND is a constant defined in mpif.h and gives the
       length of the declared integer in bytes.


NOTES
       If the file data representation is other than "native," care must be
       taken in constructing etypes and file types. Any of the data-type
       constructor functions may be used; however, for those functions that
       accept displacements in bytes, the displacements must be specified in
       terms of their values in the file for the file data representation
       being used. MPI will interpret these byte displacements as is; no
       scaling will be done. The function MPI_File_get_type_extent can be used
       to calculate the extents of data types in the file. For etypes and
       file types that are portable data types, MPI will scale any
       displacements in the data types to match the file data representation.
       Data types passed as arguments to read/write routines specify the data
       layout in memory; therefore, they must always be constructed using
       displacements corresponding to displacements in memory.


ERRORS
       Almost all MPI routines return an error value; C routines as the value
       of the function and Fortran routines in the last argument. C++
       functions do not return errors. If the default error handler is set to
       MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
       will be used to throw an MPI:Exception object.

       Before the error value is returned, the current MPI error handler is
       called. For MPI I/O function errors, the default error handler is set
       to MPI_ERRORS_RETURN. The error handler may be changed with
       MPI_File_set_errhandler; the predefined error handler
       MPI_ERRORS_ARE_FATAL may be used to make I/O errors fatal. Note that
       MPI does not guarantee that an MPI program can continue past an error.




1.4.1                            Jan 14, 2010      MPI_File_get_type_extent(3)
