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MPI_Type_create_keyval(3) man page (version 1.3.4)

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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.

       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-porta-
       ble 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++ func-
       tions 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

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