TIMER Statements

 Action

 Enable, disable, or suspend timer-event trapping.

 Syntax


  TIMER ON

  TIMER OFF

  TIMER STOP


 Remarks

  TIMER  ON enables timer-event trapping. A timer event occurs when  n
 seconds have elapsed (as specified in the  ON  TIMER statement). If a timer
 event occurs after a  TIMER  ON statement, the routine specified in the  ON
 TIMER statement is executed.

  TIMER  OFF disables timer-event trapping. No timer-event trapping takes
 place until a  TIMER  ON statement is executed. Events occurring while
 trapping is off are ignored.

  TIMER  STOP suspends timer-event trapping. No trapping takes place until a
 TIMER  ON statement is executed. Events occurring while trapping is off are
 remembered and processed when the next  TIMER  ON statement is executed.
 However, remembered events are lost if  TIMER  OFF is executed.

 When a timer-event trap occurs (that is, the  GOSUB is performed), an
 automatic  TIMER  STOP is executed so that recursive traps cannot take
 place. The  RETURN operation from the trapping routine automatically
 performs a  TIMER  ON statement unless an explicit  TIMER  OFF was performed
 inside the routine.

 For more information, see Chapter 9, "Event Handling" in the  Programmer's
 Guide.

 See Also

  ON  event,  TIMER Function

 Example


 This example uses the  ON TIMER statement to trap timer events. It draws a
 polygon every three seconds with a random shape (three to seven sides),
 size, and location.

 SCREEN 1
 DEFINT A-Z
 DIM X(6), Y(6)
 TIMER ON' Enable timer-event trapping.
 ON TIMER(3) GOSUB Drawpoly' Draw a new polygon every three seconds.
 PRINT "Press any key to end program"
 INPUT "Press <RETURN> to start",Test$

 DO
 LOOP WHILE INKEY$ = ""' End program if any key pressed.

 END

 Drawpoly.
    CLS' Erase old polygon.
    N = INT(5 * RND + 2)' N is random number from 2 to 6.
    FOR I = 0 TO N
       X(I) = INT(RND * 319)' Get coordinates of vertices of
       Y(I) = INT(RND * 199)' polygon.
    NEXT
    PSET (X(N), Y(N))
    FOR I = 0 TO N
       LINE -(X(I), Y(I)),2' Draw new polygon.
    NEXT
    RETURN