TPU$_EXITING A result of EXIT (when the default condition
handler is established).
TPU$_NONANSICRT A result of operation termination - results
when you call TPU with TPU$DISPLAYFILE
set to nodisplay and you attempt to execute
screen-oriented commands.
TPU$_QUITTING A result of QUIT (when the default condition
handler is established).
TPU$_RECOVERFAIL A recovery operation was terminated
abnormally.