The '''ON STRIG(n)''' statement is an event procedure that directs program flow upon the press of a specified joystick button.


{{PageSyntax}}
:: ON STRIG(''button_function'') GOSUB {linenumber|linelabel}


QB64 {{PageSyntax}}

:: ON STRIG(''button_function''[, ''joystick_number'']) {GOSUB {linelabel|linenumber}|sub-procedure}


* In '''QB64''' the value can be any button function number with any number of joysticks. See [[STRIG]] and [[STICK]] for parameters.
* In Qbasic, value of ''n'' can be a number from 0 to 3 only as it can only monitor 2 joystick buttons and 2 joysticks.
* There are two ''button functions'' for each button. The even numbered function is always the event of any press since last read.
* The statement sends the procedure to a line number, [[SUB]] or [[GOSUB]] procedure or line number when a button event occurs.


''Example 1:'' Reading a STRIG event to do something in a [[GOSUB]] procedure.
{{CodeStart}} '' ''
{{Cl|ON STRIG(n)|ON STRIG}}(0) {{Cl|GOSUB}} 10
{{Cl|STRIG(n)|STRIG}}(0)ON

{{Cl|DO...LOOP|DO}}
    {{Cl|PRINT}} ".";
    {{Cl|_LIMIT}} 30
{{Cl|LOOP}} {{Cl|UNTIL}} {{Cl|INKEY$}} <> ""
{{Cl|END}}

10
a$ = "[STRIG 0 EVENT]"
{{Cl|FOR...NEXT|FOR}} x = 1 {{Cl|TO}} {{Cl|LEN}}(a$)
    {{Cl|PRINT}} {{Cl|MID$}}(a$, x, 1);
    {{Cl|_DELAY}} 0.02
{{Cl|NEXT}}
{{Cl|RETURN}} '' ''
{{CodeEnd}}


''Example 2:'' Displays any number of game pad or joystick device button presses.
{{CodeStart}}
{{Cl|FOR...NEXT|FOR}} j = 1 {{Cl|TO}} 256
    {{Cl|FOR...NEXT|FOR}} b = 1 {{Cl|TO}} 256
        {{Cl|ON STRIG(n)|ON STRIG}}((b - 1) * 4, j) JoyButton (j - 1) * 256 + b - 1
    {{Cl|NEXT}}
{{Cl|NEXT}}
{{Cl|STRIG(n)|STRIG}} ON

{{Cl|DO...LOOP|DO}}
    {{Cl|PRINT}} ".";
    {{Cl|_LIMIT}} 30
{{Cl|LOOP}} {{Cl|UNTIL}} {{Cl|INKEY$}} <> ""
{{Cl|END}}

{{Cl|SUB}} JoyButton (js {{Cl|AS}} {{Cl|LONG}})
{{Cl|PRINT}} "Joystick #"; js \ 256 + 1; "button #"; (js {{Cl|AND (boolean)|AND}} 255) + 1; "pressed!"
{{Cl|END SUB}} '' ''
{{CodeEnd}}
:''Explanation:'' Up to 256 controllers can be used in QB64 with many buttons to read.


''See also:'' 
* [[STRIG ]], [[STICK]] {{text|(functions)}}
* [[STRIG(n)]] {{text|(statement)}}
* [[_DEVICES]], [[_DEVICE$]], [[_LASTBUTTON]]
* [http://en.wikipedia.org/wiki/Analog_stick Single and Dual Stick Controllers]


{{PageNavigation}}