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MPI_File_get_type_extent(3OpenMPI)                                        MPI_File_get_type_extent(3OpenMPI)



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. FOR-TRAN FORTRAN
       TRAN 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 argu-ments arguments
       ments  to  read/write routines specify the data layout in memory; therefore, they must always be con-structed constructed
       structed 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.




Open MPI 1.2                                   September 2006             MPI_File_get_type_extent(3OpenMPI)