Takes in the address of an uwind information block (UIB) and the
    GP value for a routine and returns the addresses of the start of
    the unwind descriptors (if any), the handler function descriptor
    (if any), and the operating system-specific data area (if any).
    The size in bytes of the unwind descriptors is also returned.

    Related Services

    SYS$SET_UNWIND_TABLE, SYS$CLEAR_UNWIND_TABLE, SYS$GET_UNWIND_
    ENTRY_INFO,