# append(_:) Append a buffer of bytes to the data. ``` mutating func append(_ buffer: UnsafeBufferPointer) ``` ## Parameters `buffer` The buffer of bytes to append. The size is calculated from `SourceType` and `buffer.count`. --- 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)