MPI_Type_create_keyval(3)          Open MPI          MPI_Type_create_keyval(3)



NAME
       MPI_Type_create_keyval - Generates a new attribute key for caching on
       data types.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Type_create_keyval(MPI_Type_copy_attr_function *type_copy_attr_fn,
            MPI_Type_delete_attr_function *type_delete_attr_fn,
            int *type_keyval, void *extra_state)


Fortran Syntax (see FORTRAN 77 NOTES)
       INCLUDE 'mpif.h'
       MPI_TYPE_CREATE_KEYVAL(TYPE_COPY_ATTR_FN, TYPE_DELETE_ATTR_FN,
                 TYPE_KEYVAL, EXTRA_STATE, IERROR)
            EXTERNAL TYPE_COPY_ATTR_FN, TYPE_DELETE_ATTR_FN
            INTEGER   TYPE_KEYVAL, IERROR
            INTEGER(KIND=MPI_ADDRESS_KIND) EXTRA_STATE


C++ Syntax
       #include <mpi.h>
       static int MPI::Datatype::Create_keyval(MPI::Datatype::Copy_attr_function*
            type_copy_attr_fn, MPI::Datatype::Delete_attr_function*
            type_delete_attr_fn, void* extra_state)


INPUT PARAMETERS
       type_copy_attr_fn
                 Copy callback function for type_keyval (function).

       type_delete_attr_fn
                 Delete callback function for type_keyval (function).

       extra_state
                 Extra state for callback functions.


OUTPUT PARAMETERS
       type_keyval
                 Key value for future access (integer).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPI_Type_create_keyval generates a new attribute key for caching on
       data types. This routine partially replaces MPI_Keyval_create.

       The argument type_copy_attr_fn may be specified as
       MPI_TYPE_NULL_COPY_FN or MPI_TYPE_DUP_FN from C, C++, or Fortran.
       MPI_TYPE_NULL_COPY_FN is a function that does nothing other than
       returning flag = 0 and MPI_SUCCESS. MPI_TYPE_DUP_FN is a simple-minded
       copy function that sets flag = 1, returns the value of attribute_val_in
       in attribute_val_out, and returns MPI_SUCCESS.

       The argument type_delete_attr_fn may be specified as
       MPI_TYPE_NULL_DELETE_FN from C, C++, or Fortran.
       MPI_TYPE_NULL_DELETE_FN is a function that does nothing beyond
       returning MPI_SUCCESS.  The C callback functions are:

       typedef int MPI_Type_copy_attr_function(MPI_Datatype oldtype,
                   int type_keyval, void *extra_state, void *attribute_val_in,
                   void *attribute_val_out, int *flag);
       and
       typedef int MPI_Type_delete_attr_function(MPI_Datatype type, int type_keyval,
                    void *attribute_val, void *extra_state);

       The Fortran callback functions are:

       SUBROUTINE TYPE_COPY_ATTR_FN(OLDTYPE, TYPE_KEYVAL, EXTRA_STATE,
                    ATTRIBUTE_VAL_IN, ATTRIBUTE_VAL_OUT, FLAG, IERROR)
           INTEGER OLDTYPE, TYPE KEYVAL, IERROR
           INTEGER(KIND=MPI_ADDRESS_KIND) EXTRA_STATE,
               ATTRIBUTE_VAL_IN, ATTRIBUTE_VAL_OUT
           LOGICAL FLAG
       and
       SUBROUTINE TYPE_DELETE_ATTR_FN(TYPE, TYPE_KEYVAL, ATTRIBUTE_VAL, EXTRA_STATE,
                    IERROR)
           INTEGER TYPE, TYPE_KEYVAL, IERROR
           INTEGER(KIND=MPI_ADDRESS_KIND) ATTRIBUTE VAL, EXTRA_STATE

       The C++ callbacks are:

       typedef int MPI::Datatype::Copy_attr_function(const MPI::Datatype& oldtype,
                    int type_keyval, void* extra_state,
                    const void* attribute_val_in, void* attribute_val_out,
                    bool& flag);
       and
       typedef int MPI::Datatype::Delete_attr_function(MPI::Datatype& type,
                    int type_keyval, void* attribute_val, void* extra_state);



FORTRAN 77 NOTES
       The MPI standard prescribes portable Fortran syntax for the EXTRA_STATE
       argument only for Fortran 90.  FORTRAN 77 users may use the non-
       portable syntax

            INTEGER*MPI_ADDRESS_KIND EXTRA_STATE

       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.


SEE ALSO
       MPI_Type_free_keyval




1.4.1                            Jan 14, 2010        MPI_Type_create_keyval(3)
