PEN enables, disables, or suspends light-pen event trapping.
If event trapping is enabled, ON PEN branches to a subroutine whenever
the light pen is activated.
 
PEN ON
PEN OFF
PEN STOP
ON PEN GOSUB line
 
    - PEN ON      Enables light-pen event trapping.
    - PEN OFF     Disables light-pen event trapping.
    - PEN STOP    Suspends light-pen event trapping. Events are processed
                  once event trapping is enabled by PEN ON.
    - line        The label or number of the first line of the
                  event-trapping subroutine.
 
Example:
    'This example requires a light pen.
    ON PEN GOSUB Handler
    PEN ON
    PRINT "Press Esc to exit."
    DO UNTIL INKEY$ = CHR$(27): LOOP
    END
 
Handler:
    PRINT "Pen is at row"; PEN(6); ", column"; PEN(7)
    RETURN
 
 
See Also    <PEN FUNCTION>