# gestureRecognizer(_:shouldBeRequiredToFailBy:) Asks the delegate if a gesture recognizer should be required to fail by another gesture recognizer. ``` optional func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldBeRequiredToFailBy otherGestureRecognizer: UIGestureRecognizer) -> Bool ``` ## Parameters `gestureRecognizer` An instance of a subclass of the abstract base class [`UIGestureRecognizer`](/documentation/UIKit/UIGestureRecognizer). This is the object sending the message to the delegate. `otherGestureRecognizer` An instance of a subclass of the abstract base class [`UIGestureRecognizer`](/documentation/UIKit/UIGestureRecognizer). ## Return Value to set up a dynamic failure requirement between `gestureRecognizer` and `otherGestureRecognizer`. The default implementation returns —`gestureRecognizer` isn’t required to fail by `otherGestureRecognizer`. ## Discussion This method is called once per attempt to recognize, so failure requirements can be determined lazily and may be set up between recognizers across view hierarchies. Note that returning is guaranteed to set up the failure requirement; returning , on the other hand, isn’t guaranteed to prevent or remove a failure requirement because `otherGestureRecognizer` might make itself a failure requirement by using its own subclass or delegate methods. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)