The NCS$RESTORE_CF routine, used in conjunction with the
    NCS$SAVE_CF routine, permits the application program to keep a
    local copy of the conversion function. The NCS$SAVE_CF routine
    obtains the length and location of the conversion function and
    returns it to the application program. The application program
    subsequently provides this information to the NCS$RESTORE_CF
    routine, which uses it to access the conversion function.

    This routine also does some integrity checking on the conversion
    function as it is being processed.