why i need the parameter "&b0" in
it s also work without &b0.
Dear Dominik Loher:
As you see the function prototype is " void attachPop(NexTouchEventCb pop, void *ptr = NULL)"
So "&b0" is just an input paramter which is passed to the "b0PopCallback" function.
If you do not need any paramter in your user-defined callback function ,you can just pass a "NULL" to it.