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.