_BUTTONCHANGE - mkilgore/QB64pe GitHub Wiki

The _BUTTONCHANGE function returns -1 or 1 when a specified button number on a controller device has been pressed or released.

press% = _BUTTONCHANGE(button_number%)

• Values returned are -1 for a press and 1 when a button is released. No press or release event returns zero.
• The button_number% must be a number which does not exceed the number of buttons found by the _LASTBUTTON function.
• The number of _DEVICES must be read before using _DEVICE$, _DEVICEINPUT or _LASTBUTTON.
• Note: The center mouse button is button number 2. Center can also be read using _MOUSEBUTTON(3).

Example: Reading multiple controller device buttons, axis and wheels.

DO...LOOP
  d& = _DEVICEINPUT
  IF...THEN d& THEN '             the device number cannot be zero!
    PRINT "Found"; d&;
    FOR...NEXT b = 1 TO _LASTBUTTON(d&)
      PRINT _BUTTONCHANGE(b); _BUTTON(b);
    NEXT
    FOR...NEXT a = 1 TO _LASTAXIS(d&)
      PRINT _AXIS(a);
    NEXT
    FOR...NEXT w = 1 TO _LASTWHEEL(d&)
      PRINT _WHEEL(w);
    NEXT
    PRINT
  END IF
LOOP UNTIL INKEY$ = CHR$(27) 'escape key exit

END '' ''

Note: When there is no device control to read, a FOR n = 1 TO 0 loop will not run thus avoiding a control function read error.

• _LASTWHEEL, _LASTBUTTON, _LASTAXIS
• _AXIS, _WHEEL, _BUTTON
• _DEVICE$, _DEVICES
• _MOUSEBUTTON
• Controller Devices