NAME

       MPI_Win_create_keyval - Creates a keyval for a window.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Win_create_keyval(MPI_Win_copy_attr_function *win_copy_attr_fn,
            MPI_Win_delete_attr_function *win_delete_attr_fn,
            int *win_keyval, void *extra_state)

Fortran Syntax (see FORTRAN 77 NOTES)

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_WIN_CREATE_KEYVAL(WIN_COPY_ATTR_FN, WIN_DELETE_ATTR_FN,
            WIN_KEYVAL, EXTRA_STATE, IERROR)
            EXTERNAL WIN_COPY_ATTR_FN, WIN_DELETE_ATTR_FN
            INTEGER WIN_KEYVAL, IERROR
            INTEGER(KIND=MPI_ADDRESS_KIND) EXTRA_STATE

Fortran 2008 Syntax

       USE mpi_f08
       MPI_Win_create_keyval(win_copy_attr_fn, win_delete_attr_fn, win_keyval,
                 extra_state, ierror)
            PROCEDURE(MPI_Win_copy_attr_function) :: win_copy_attr_fn
            PROCEDURE(MPI_Win_delete_attr_function) :: win_delete_attr_fn
            INTEGER, INTENT(OUT) :: win_keyval
            INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: extra_state
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

C++ Syntax

       #include <mpi.h>
       static int MPI::Win::Create_keyval(MPI::Win::Copy_attr_function*
            win_copy_attr_fn,
            MPI::Win::Delete_attr_function* win_delete_attr_fn,
            void* extra_state)

INPUT PARAMETERS

       win_copy_attr_fn
                 Copy callback function for win_keyval (function).

       win_delete_attr_fn
                 Delete callback function for win_keyval (function).

       extra_state
                 Extra state for callback functions.

OUTPUT PARAMETERS

       win_keyval
                 Key value for future access (integer).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       The  argument  win_copy_attr_fn may be specified as MPI_WIN_NULL_COPY_FN or MPI_WIN_DUP_FN
       from either C, C++, or Fortran. MPI_WIN_NULL_COPY_FN is a function  that  serves  only  to
       return flag = 0 and MPI_SUCCESS. MPI_WIN_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 win_delete_attr_fn may be specified as MPI_WIN_NULL_DELETE_FN from either C,
       C++, or  Fortran.  MPI_WIN_NULL_DELETE_FN  is  a  function  that  serves  only  to  return
       MPI_SUCCESS.

       The C callback functions are:

       typedef int MPI_Win_copy_attr_function(MPI_Win oldwin, int win_keyval,
                    void *extra_state, void *attribute_val_in,
                    void *attribute_val_out, int *flag);

       and

       typedef int MPI_Win_delete_attr_function(MPI_Win win, int win_keyval,
                    void *attribute_val, void *extra_state);

       The Fortran callback functions are:

       SUBROUTINE WIN_COPY_ATTR_FN(OLDWIN, WIN_KEYVAL, EXTRA_STATE,
            ATTRIBUTE_VAL_IN, ATTRIBUTE_VAL_OUT, FLAG, IERROR)
            INTEGER OLDWIN, WIN_KEYVAL, IERROR
            INTEGER(KIND=MPI_ADDRESS_KIND) EXTRA_STATE, ATTRIBUTE_VAL_IN,
                 ATTRIBUTE_VAL_OUT
            LOGICAL FLAG

       and

       SUBROUTINE WIN_DELETE_ATTR_FN(WIN, WIN_KEYVAL, ATTRIBUTE_VAL,
            EXTRA_STATE, IERROR)
            INTEGER WIN, WIN_KEYVAL, IERROR
            INTEGER(KIND=MPI_ADDRESS_KIND) ATTRIBUTE_VAL, EXTRA_STATE

       The C++ callbacks are:

       typedef int MPI::Win::Copy_attr_function(const MPI::Win& oldwin,
            int win_keyval, void* extra_state, void* attribute_val_in,
            void* attribute_val_out, bool& flag);

       and

       typedef int MPI::Win::Delete_attr_function(MPI::Win& win, int win_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.