# enumerateBytes(_:) Enumerates the contents of the data’s buffer. ``` func enumerateBytes(_ block: (UnsafeBufferPointer, Data.Index, inout Bool) -> Void) ``` ## Parameters `block` The closure to invoke for each region of data. You may stop the enumeration by setting the `stop` parameter to `true`. ## Discussion In some cases, (for example, a [`Data`](/documentation/Foundation/Data) backed by a `dispatch_data_t`, the bytes may be stored discontiguously. In those cases, this function invokes the closure for each contiguous region of bytes. --- 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)