17.2.393. MPI_Type_extent

MPI_Type_extent - Returns the extent of a data type, the difference between the upper and lower bounds of the data type – use of this routine is deprecated.

17.2.393.1. SYNTAX

17.2.393.1.1. C Syntax

#include <mpi.h>

int MPI_Type_extent(MPI_Datatype datatype, MPI_Aint *extent)

17.2.393.1.2. Fortran Syntax

INCLUDE 'mpif.h'
MPI_TYPE_EXTENT(DATATYPE, EXTENT, IERROR)
     INTEGER DATATYPE, EXTENT, IERROR

17.2.393.2. INPUT PARAMETER

  • datatype: Datatype (handle).

17.2.393.3. OUTPUT PARAMETERS

  • extent: Datatype extent (integer).

  • IERROR: Fortran only: Error status (integer).

17.2.393.4. DESCRIPTION

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

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).

17.2.393.5. ERRORS

Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.

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.