# CFDataCreate(_:_:_:) Creates an immutable CFData object using data copied from a specified byte buffer. ``` func CFDataCreate(_ allocator: CFAllocator!, _ bytes: UnsafePointer!, _ length: CFIndex) -> CFData! ``` ## Parameters `allocator` The allocator to use to allocate memory for the new object. Pass `NULL` or kCFAllocatorDefault to use the current default allocator. `bytes` A pointer to the byte buffer that contains the raw data to be copied into `theData`. `length` The number of bytes in the buffer (`bytes`). ## Return Value A new CFData object, or `NULL` if there was a problem creating the object. Ownership follows the [The Create Rule](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html#//apple_ref/doc/uid/20001148-103029). ## Discussion You must supply a count of the bytes in the buffer. This function always copies the bytes in the provided buffer into internal storage. --- 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)