MPI_Keyval_create(3)							MPI						      MPI_Keyval_create(3)

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 PARAMETER

       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 programers 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 depre-
       cated.  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

LOCATION

       keyval_create.c

								     7/21/2010						      MPI_Keyval_create(3)