The cleanup routine is the final routine called in each
    interaction with TPU. It tells TPU to clean up its internal
    data structures and prepare for additional invocations. You can
    control what is reset by this routine by setting or clearing the
    flags described previously.

    When you finish with TPU, call this routine to free the memory
    and restore the characteristics of the terminal to their original
    settings.

    If you intend to exit after calling TPU$CLEANUP, do not
    delete the data structures; the operating system does this
    automatically. Allowing the operating system to delete the
    structures improves the performance of your program.

    Notes

    1. When you use the simplified interface, TPU automatically
       sets the following flags:

       o  TPU$V_RESET_TERMINAL

       o  TPU$V_DELETE_BUFFERS

       o  TPU$V_DELETE_JOURNAL

       o  TPU$V_DELETE_WINDOWS

       o  TPU$V_DELETE_EXITH

       o  TPU$V_EXECUTE_PROC

       o  TPU$V_EXECUTE_FILE

       o  TPU$V_PRUNE_CACHE

       o  TPU$V_KILL_PROCESSES

    2. If this routine does not return a success status, no other
       calls to the editor should be made.