use interrupts on C-level

I'm working on a native class to recognize gestures.
Input will be a distance sensor HC-SR04.
To recognize a gesture something like setWatch is used.
Its running up to the point that an interupt is recognized, but there are no args that would help to assign the interupt to a parent.
Any idea ?

void gotInterrupt(int n, ... ){ jsWarn("got it %j",n); }
void jswrap_Gesture_scan(JsVar *parent){
  JsGesture gest;
  if(!getFromVar(&gest,parent)) return;
  IOEventFlags exti = EV_NONE;
  if (!jsiIsWatchingPin(gest.data.echo))
    exti = jshPinWatch(gest.data.echo, true);
    // disable event callbacks by default
  if (exti) {
	jshSetEventCallback(exti, 0);
	JsVar *fn = jsvNewNativeFunction((void (*)(void))gotInterrupt, JSWAT_VOID|JSWAT_THIS_ARG|(JSWAT_JSVAR<<JSWAT_BITS));
    if (!fn) return;
    jshSetEventCallback(exti, (JshEventCallbackCallback)jsvGetNativeFunctionPtr(fn));
	jsvUnLock(fn);
  }
}