Application should unregister the event by setting handle to zero. If the session was closed before the event was unregistered, it will cause a handle leak in DSP process.

DSP can hold up to 6 concurrent registrations. More than that will cause registration to fail.

Interrupts with interupt=2 are related to pipes. The channel argument is the same as the pipe channel argument. The interrupt is signalled when data is available on the related pipe or when a related event occurs.