# CFAllocatorCreate(_:_:) Creates an allocator object. ``` func CFAllocatorCreate(_ allocator: CFAllocator!, _ context: UnsafeMutablePointer!) -> Unmanaged! ``` ## Parameters `allocator` The existing allocator to use to allocate memory for the new allocator. Pass the [`kCFAllocatorUseContext`](/documentation/CoreFoundation/kCFAllocatorUseContext) constant for this parameter to allocate memory using the appropriate function callback specified in the `context` parameter. Pass `NULL` or [`kCFAllocatorDefault`](/documentation/CoreFoundation/kCFAllocatorDefault) to allocate memory for the new allocator using the default allocator. `context` A structure of type [`CFAllocatorContext`](/documentation/CoreFoundation/CFAllocatorContext). The fields of this structure hold (among other things) function pointers to callbacks used for allocating, reallocating, and deallocating memory. ## Return Value The new allocator object, or `NULL` if there was a problem allocating memory. 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 use this function to create custom allocators which you can then pass into various Core Foundation object-creation functions. You must implement a function callback that allocates memory and assign it to the `allocate` field of this structure. You typically also implement deallocate, reallocate, and preferred-size callbacks. --- 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)