Function

CFNotificationCenterAddObserver(_:_:_:_:_:_:)

Registers an observer to receive notifications.

Declaration

func CFNotificationCenterAddObserver(_ center: CFNotificationCenter!, _ observer: UnsafeRawPointer!, _ callBack: CFNotificationCallback!, _ name: CFString!, _ object: UnsafeRawPointer!, _ suspensionBehavior: CFNotificationSuspensionBehavior)

Parameters

center

The notification center to which to add the observer.

observer

The observer. In macOS 10.3 and later, this parameter may be NULL.

callBack

The callback function to call when object posts the notification named name.

name

The name of the notification to observe. If NULL, callback is called for any notification posted by object.

If center is a Darwin notification center, this value must not be NULL.

object

The object to observe. For distributed notifications, object must be a CFString object. If NULL, callback is called when a notification named name is posted by any object.

If center is a Darwin notification center, this value is ignored.

suspensionBehavior

Flag indicating how notifications should be handled when the application is in the background. See CFNotificationSuspensionBehavior for the list of available values.

If center is a Darwin notification center, this value is ignored.

Discussion

Notification delivery is registered for the main thread.

If you need to control which thread processes a notification, your callback function must be able to forward the notification to the proper thread. You can use a CFMessagePort object or a custom CFRunLoopSource object to send notifications to the correct thread’s run loop.

See Also

Adding and Removing Observers