Returns a Boolean value that indicates whether a run loop mode contains a particular CFRunLoopObserver object.


func CFRunLoopContainsObserver(_ rl: CFRunLoop!, _ observer: CFRunLoopObserver!, _ mode: CFRunLoopMode!) -> Bool



The run loop to examine.


The run loop observer for which to search.


The run loop mode in which to search for observer. Use the constant commonModes to search for observer in the set of objects monitored by all the common modes.

Return Value

true if observer is in mode mode of the run loop rl, otherwise false.


If observer was added to commonModes, this function returns true if mode is either commonModes or any of the modes that has been added to the set of common modes.

See Also

Managing Observers

func CFRunLoopAddObserver(CFRunLoop!, CFRunLoopObserver!, CFRunLoopMode!)

Adds a CFRunLoopObserver object to a run loop mode.

func CFRunLoopRemoveObserver(CFRunLoop!, CFRunLoopObserver!, CFRunLoopMode!)

Removes a CFRunLoopObserver object from a run loop mode.

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