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MPI_Type_get_true_extent(3OpenMPI)                                        MPI_Type_get_true_extent(3OpenMPI)



NAME
       MPI_Type_get_true_extent  -  Returns  the  true lower bound and extent of a data type's corresponding
       typemap, ignoring MPI_UB and MPI_LB markers.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Type_get_true_extent(MPI_Datatype datatype,
            MPI_Aint *true_lb, MPI_Aint *true_extent)


Fortran Syntax (see FORTRAN 77 NOTES)
       INCLUDE 'mpif.h'
       MPI_TYPE_GET_TRUE_EXTENT(DATATYPE, TRUE_LB, TRUE_EXTENT, IERROR)
            INTEGER   DATATYPE, IERROR
            INTEGER(KIND=MPI_ADDRESS_KIND) TRUE_LB, TRUE_EXTENT


C++ Syntax
       #include <mpi.h>
       void MPI::Datatype::Get_true_extent(MPI::Aint& true_lb,
            MPI::Aint& true_extent) const


INPUT PARAMETER
       datatype  Data type for which information is wanted (handle).


OUTPUT PARAMETERS
       true_lb   True lower bound of data type (integer).

       true_extent
                 True size of data type (integer).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       The true_lb parameter returns the offset of the lowest unit of store that is addressed  by  the  data
       type, that is, the lower bound of the corresponding typemap, ignoring MPI_LB markers. The true_extent
       parameter returns the true size of the data type, that is, the extent of the  corresponding  typemap,
       ignoring MPI_LB and MPI_UB markers, and performing no rounding for alignment.

       The true_extent is the minimum number of bytes of memory necessary to hold a data type, uncompressed.

       See Section 4.14.3 of the MPI-2 standard for more detailed definitions of these parameters  in  rela-tion relation
       tion to the typemap.


FORTRAN 77 NOTES
       The  MPI  standard  prescribes portable Fortran syntax for the TRUE_LB and TRUE_EXTENT arguments only
       for Fortran 90. FORTRAN 77 users may use the non-portable syntax

            INTEGER*MPI_ADDRESS_KIND TRUE_LB
       or
            INTEGER*MPI_ADDRESS_KIND TRUE_EXTENT

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


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. By default,  this  error
       handler  aborts  the  MPI  job, except for I/O function errors. The error handler may be changed with
       MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be used  to  cause  error
       values  to  be  returned.  Note  that MPI does not guarantee that an MPI program can continue past an
       error.





Open MPI 1.2                                   September 2006             MPI_Type_get_true_extent(3OpenMPI)