NAME

       MPI_Keyval_create -  Greates a new attribute key

SYNOPSIS

       int MPI_Keyval_create(MPI_Copy_function *copy_fn,
                            MPI_Delete_function *delete_fn,
                            int *keyval, void *extra_state)

INPUT PARAMETERS

       copy_fn
              - Copy callback function for keyval

       delete_fn
              - Delete callback function for keyval

       extra_state
              - Extra state for callback functions

OUTPUT PARAMETERS

       keyval - key value for future access (integer)

NOTES

       Key values are global (available for any and all communicators).

       There  are  subtle differences between C and Fortran that require that the copy_fn be written in the same
       language that MPI_Keyval_create is called from.  This should not  be  a  problem  for  most  users;  only
       programmers using both Fortran and C in the same program need to be sure that they follow this rule.

THREAD AND INTERRUPT SAFETY

       This routine is thread-safe.  This means that this routine may be safely used by multiple threads without
       the  need  for  any  user-provided thread locks.  However, the routine is not interrupt safe.  Typically,
       this is due to the use of memory allocation routines such as malloc or other non-MPICH  runtime  routines
       that are themselves not interrupt-safe.

DEPRECATED FUNCTION

       The  MPI-2 standard deprecated a number of routines because MPI-2 provides better versions.  This routine
       is one of those that was deprecated.  The routine may continue to be used, but new code  should  use  the
       replacement routine.  The replacement for this routine is MPI_Comm_create_keyval .

NOTES FOR FORTRAN

       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.

ERRORS

       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.  Before the value is returned, the current MPI  error
       handler  is called.  By default, this error handler aborts the MPI job.  The error handler may be changed
       with   MPI_Comm_set_errhandler   (for   communicators),   MPI_File_set_errhandler   (for   files),    and
       MPI_Win_set_errhandler  (for  RMA windows).  The MPI-1 routine MPI_Errhandler_set may be used but its use
       is deprecated.  The predefined error handler MPI_ERRORS_RETURN may be used to cause error  values  to  be
       returned.   Note that MPI does not guarentee that an MPI program can continue past an error; however, MPI
       implementations will attempt to continue whenever possible.

       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_INTERN
              - This error is returned when some part of the MPICH implementation is unable to acquire memory.
       MPI_ERR_ARG
              - Invalid argument.  Some argument is invalid and is not identified  by  a  specific  error  class
              (e.g., MPI_ERR_RANK ).

SEE ALSO

       MPI_Keyval_free, MPI_Comm_create_keyval

                                                    11/9/2015                               MPI_Keyval_create(3)