HP 3000 Manuals

System Debug Reference Manual

Control-Y 

System Debug allows the user to prematurely terminate command execution
by entering a Control-Y (press and hold the CONTROL key and press Y).
Command loops, display loops and modification loops can be interrupted
with this mechanism.

When Control-Y is entered during window updates, interrupted output lines
may disturb portions of the windows.  When this occurs, redraw the
windows with the RED (redraw) command.


NOTE  There is only one Control-Y handler per session.  When Debug is
      entered, it takes ownership of the Control-Y handler.  When Debug
      is exited, it returns the Control-Y handler to the process that
      owned it when Debug was entered.

      If other processes are active in a session while Debug is being
      used, it is possible for one of the other process to steal
      Control-Y ownership from Debug.  In this situation, when Debug
      exits it will, in effect, steal Control-Y back from the current
      owner and give it to the process that owned it when Debug was
      entered.  If Control-Y is stolen from Debug, it is also possible to
      create infinite loops in Debug from which there is no way out (for
      example, "while TRUE do {}").

      Both DAT and Debug rearm the Control-Y trap after every CI command
      (for example, the ":" command).

MPE/iX 5.0 Documentation