Installs an event monitor that receives copies of events posted to other applications.
- macOS 10.6+
An event mask specifying which events you wish to monitor. See
NSEventfor possible values.
.Event Type Mask
The event handler block object. It is passed the event to monitor. You are unable to change the event, merely observe it.
An event handler object.
Events are delivered asynchronously to your app and you can only observe the event; you cannot modify or otherwise prevent the event from being delivered to its original target application.
Key-related events may only be monitored if accessibility is enabled or if your application is trusted for accessibility access (see
Note that your handler will not be called for events that are sent to your own application.
In OS X v 10.6, event monitors are only able to monitor the following event types: