MPI_Type_create_keyval - Create a datatype attribute key

       If an error occurs in an MPI function, the current MPI error handler is called to handle it.  By default,
       this error handler aborts the MPI job.  The error handler may be changed with  MPI_Errhandler_set  ;  the
       predefined  error  handler  MPI_ERRORS_RETURN  may be used to cause error values to be returned (in C and
       Fortran; this error handler is less useful in with the C++ MPI bindings.  The  predefined  error  handler
       MPI::ERRORS_THROW_EXCEPTIONS  should be used in C++ if the error value needs to be recovered).  Note that
       MPI does not guarantee that an MPI program can continue past an error.

       All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error value; C routines as the value of  the
       function and Fortran routines in the last argument.  The C++ bindings for MPI do not return error values;
       instead,  error  values  are  communicated  by  throwing  exceptions  of  type MPI::Exception (but not by
       default).  Exceptions are only thrown if the error value is not MPI::SUCCESS .

       Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI functions will return upon an error,
       there will be no way to recover what the actual error value was.
       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_TYPE
              - Invalid datatype argument.  May be an uncommitted MPI_Datatype (see MPI_Type_commit ).
       MPI_ERR_OTHER
              - Other error; the error code associated with this error indicates an attempt to  use  an  invalue
              keyval.
       MPI_ERR_ARG
              -  Invalid  argument.   Some  argument is invalid and is not identified by a specific error class.
              This is typically a NULL pointer or other such error.

copyfunc
              - Copy callback function for type_keyval (function)
       delfunc
              - Delete callback function for type_keyval (function)
       extra  - extra state for callback functions

       tcreatekey.c

LAM/MPI 7.1.4                                       6/24/2006                          MPI_Type_create_keyval(3)

       For more information, please see the official MPI Forum web site, which contains the  text  of  both  the
       MPI-1 and MPI-2 standards.  These documents contain detailed information about each MPI function (most of
       which is not duplicated in these man pages).

       http://www.mpi-forum.org/

       MPI_Type_create_keyval -  Create a datatype attribute key

       All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the
       end of the argument list.  ierr is an integer and has the same meaning as the return value of the routine
       in C.  In Fortran, MPI routines are subroutines, and are invoked with the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.

key    - key value for future access (integer)

MPI_Type_free_keyval(3), MPI_Type_get_attr(3), MPI_Type_set_attr(3), MPI_Type_delete_attr(3)

       #include <mpi.h>
       int
       MPI_Type_create_keyval(MPI_Type_copy_attr_function *cpyfunc,
                              MPI_Type_delete_attr_function *delfunc, int *key,
                              void *extra)

       The  IMPI  standard  only  supports  MPI-1  functions.  Hence, this function is currently not designed to
       operate within an IMPI job.