# CFDictionaryCopyDescriptionCallBack Prototype of a callback function used to get a description of a value or key in a dictionary. ``` typealias CFDictionaryCopyDescriptionCallBack = (UnsafeRawPointer?) -> Unmanaged? ``` ## Parameters `value` The value to be described. ## Return Value A text description of `value`. ## Discussion This callback is passed to [`CFDictionaryCreate(_:_:_:_:_:_:)`](/documentation/CoreFoundation/CFDictionaryCreate(_:_:_:_:_:_:)) in a [`CFDictionaryKeyCallBacks`](/documentation/CoreFoundation/CFDictionaryKeyCallBacks) structure or [`CFDictionaryValueCallBacks`](/documentation/CoreFoundation/CFDictionaryValueCallBacks). This callback is used by the [`CFCopyDescription(_:)`](/documentation/CoreFoundation/CFCopyDescription(_:)) function. --- 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)