# decodeValue(ofObjCType:at:size:) Decodes a single value of a known type from the specified data buffer. ``` func decodeValue(ofObjCType type: UnsafePointer, at data: UnsafeMutableRawPointer, size: Int) ``` ## Parameters `type` The Objective-C type to decode. `data` The data buffer to decode from. `size` The size of the data buffer. ## Discussion The `type` parameter must contain exactly one type code, and the buffer specified by `data` must be large enough to hold the value corresponding to that type code. For information on creating an Objective-C type code suitable for `type`, see [`Type Encodings`](/documentation/Foundation/NSMethodSignature#Type-Encodings). Subclasses must override this method and provide an implementation to decode the value. In your overriding implementation, decode the value into the buffer beginning at data. This method matches an [`encodeValue(ofObjCType:at:)`](/documentation/Foundation/NSCoder/encodeValue(ofObjCType:at:)) message used during encoding. --- 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)