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)

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_FILE_GET_TYPE_EXTENT(FH, DATATYPE, EXTENT, IERROR)
            INTEGER   FH, DATATYPE, IERROR
            INTEGER(KIND=MPI_ADDRESS_KIND)     EXTENT

Fortran 2008 Syntax

       USE mpi_f08
       MPI_File_get_type_extent(fh, datatype, extent, ierror)
            TYPE(MPI_File), INTENT(IN) :: fh
            TYPE(MPI_Datatype), INTENT(IN) :: datatype
            INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(OUT) :: extent
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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.

4.1.6                                             Sep 30, 2023                       MPI_File_get_type_extent(3)