# attachedMode(of:) Returns the propagation mode of an attachment you identify with a key path to a key definition that supplies a default, without retrieving the value. ``` func attachedMode(of keyPath: KeyPath>) -> CVAttachmentMode? ``` ## Parameters `keyPath` A key path to a key definition that supplies a default value. ## Return Value The propagation mode of the attachment, or `nil` if the key isn’t attached. ## Discussion Use this method to check for the presence of a specific key without converting its value. Because this kind of key supplies a default, reading it as a property always produces a value, whether or not the buffer carries an attachment for it. This method returns `nil` in the second case, which makes it the way to tell an attached value from a defaulted one. --- 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)