NAME

       MPI_Type_lb - Returns the lower bound of a data type -- use of this routine is deprecated.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Type_lb(MPI_Datatype datatype, MPI_Aint *displacement)

Fortran Syntax

       INCLUDE 'mpif.h'
       MPI_TYPE_LB(DATATYPE, DISPLACEMENT, IERROR)
            INTEGER   DATATYPE, DISPLACEMENT, IERROR

INPUT PARAMETER

       datatype  Datatype (handle).

OUTPUT PARAMETERS

       displacement
                 Displacement of lower bound from origin, in bytes (integer).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

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

       This deprecated routine is not available in C++.

       MPI_Type_lb returns the lower bound of a data type. This may differ from zero if the  type
       was constructed using MPI_LB.

       The  "pseudo-datatypes,"  MPI_LB  and MPI_UB, can be used, respectively, to mark the lower
       bound (or the upper bound) of a datatype. These pseudo-datatypes occupy no  space  (extent
       (MPI_LB)  = extent (MPI_UB) =0. They do not affect the size or count of a datatype, and do
       not affect the context of a message created with this datatype. However,  they  do  affect
       the  definition  of  the  extent  of  a  datatype  and, therefore, affect the outcome of a
       replication of this datatype by a datatype constructor.

       In general, if

           Typemap = {(type0, disp0), ..., (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

       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.

SEE ALSO

       MPI_Type_get_extent