# enumerateBytes(_:) Enumerates each range of bytes in the data object using a block. ``` func enumerateBytes(_ block: (UnsafeRawPointer, NSRange, UnsafeMutablePointer) -> Void) ``` ## Parameters `block` The block to apply to byte ranges in the array. The block takes three arguments: - bytes: The bytes for the current range. This pointer is valid until the data object is deallocated. - byteRange: The range of the current data bytes. - stop: A reference to a Boolean value. The block can set the value to to stop further processing of the data. The stop argument is an out-only argument. You should only ever set this Boolean to within the Block. ## Discussion The enumeration block is called once for each contiguous region of memory in the receiver (once total for a contiguous [NSData](https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/PropertyLists/OldStylePlists/OldStylePLists.html#//apple_ref/doc/uid/20001012-47169) object), until either all bytes have been enumerated, or the `stop` parameter is set to . --- 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)