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.

4.1.6                                             Sep 30, 2023                          MPI_Win_create_keyval(3)