GSEvent is a group of C functions that passes events around the whole system. GSEvent is the low-level implementation of UIEvent.
GSEvents are sent using Mach messages. A basic event consists of the following information:
- The type of event.
- Location and time of the event.
- Which process sent the event.
- Which window should receive the event.
Purple system event port
The "Purple system event port" is the Mach port that receives system events (e.g. kGSEventLockDevice). This port is registered whenever the --RegisterForSystemEvents flag is provided to a UIKit application, or it is the first application that registers the com.apple.eventpump service for bootstrap lookup. In the other words, these system events are directed to SpringBoard.