# decodeBytes(forKey:returnedLength:) Decodes a buffer of data that was previously encoded with [`encodeBytes(_:length:forKey:)`](/documentation/Foundation/NSCoder/encodeBytes(_:length:forKey:)) and associated with the string `key`. ``` func decodeBytes(forKey key: String, returnedLength lengthp: UnsafeMutablePointer?) -> UnsafePointer? ``` ## Discussion The buffer’s length is returned by reference in `lengthp`. The returned bytes are immutable. Subclasses must override this method if they perform keyed coding. ## See Also [`- encodeBytes:length:forKey:`](/documentation/Foundation/NSCoder/encodeBytes(_:length:forKey:)) Encodes a buffer of data, given its length and a pointer, and associates it with a string key. --- 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)