MPI_Type_extent.3.rst

MPI_Type_extent

:ref:`MPI_Type_extent` - Returns the extent of a data type -- |deprecated_favor| :ref:`MPI_Type_get_extent`.

SYNTAX

C Syntax

#include <mpi.h>

int MPI_Type_extent(MPI_Datatype datatype, MPI_Aint *extent)

Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'

MPI_TYPE_EXTENT(DATATYPE, EXTENT, IERROR)
     INTEGER DATATYPE, EXTENT, IERROR

INPUT PARAMETER

• datatype: Datatype (handle).

OUTPUT PARAMETERS

• extent: Datatype extent (integer).
• ierror: Fortran only: Error status (integer).

DESCRIPTION

Note that use of this routine is deprecated as of MPI-2. Please use :ref:`MPI_Type_get_extent` instead.

:ref:`MPI_Type_extent` returns the extent of a data type, the difference between the upper and lower bounds of the data type.

In general, if

Typemap = {(type(0), disp(0)), ..., (type(n-1), disp(n-1))}

then the lower bound of Typemap is defined to be

            ( min(j) disp(j)                         if no entry has
lb(Typemap)=(                                        basic type lb
            (min(j) {disp(j) such that type(j) = lb} otherwise

Similarly, the upper bound of Typemap is defined to be

            (max(j) disp(j) + sizeof(type(j)) + e    if no entry has
ub(Typemap)=(                                        basic type ub
            (max(j) {disp(j) such that type(j) = ub} otherwise

Then

extent(Typemap) = ub(Typemap) - lb(Typemap)

If type(i) requires alignment to a byte address that is a multiple of k(i), then e is the least nonnegative increment needed to round extent(Typemap) to the next multiple of max(i) k(i).

ERRORS

.. seealso::
   * :ref:`MPI_Type_get_extent`