How do I capture and cancel a mouse scroll event using NSEvent framework in Mac OSX?

Question

I'm using NSEvent with global monitoring, to listen to mouse scroll events. However, the event is still being passed to other applications as usual. I would like to cancel the event so that only my application can interpret the event then cancel it so that other applications don't see the scroll event. What's the best way to do this?

Answer 1

As far as I know, global monitors are only designed to listen to events. You have to use the lower level CGEventTap C API to actually capture and modify (including delete) events in the stream.