# CFStringCreateWithCharacters(_:_:_:) Creates a string from a buffer of Unicode characters. ``` func CFStringCreateWithCharacters(_ alloc: CFAllocator!, _ chars: UnsafePointer!, _ numChars: CFIndex) -> CFString! ``` ## Parameters `alloc` The allocator to use to allocate memory for the new string. Pass `NULL` or [`kCFAllocatorDefault`](/documentation/CoreFoundation/kCFAllocatorDefault) to use the current default allocator. `chars` The buffer of Unicode characters to copy into the new string. `numChars` The number of characters in the buffer pointed to by `chars`. Only this number of characters will be copied to internal storage. ## Return Value An immutable string containing `chars`, 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 This function creates an immutable string from a client-supplied Unicode buffer. You must supply a count of the characters in the buffer. This function always copies the characters in the provided buffer into internal storage. To save memory, this function might choose to store the characters internally in a 8-bit backing store. That is, just because a buffer of `UniChar` characters was used to initialize the object does not mean you will get back a non-`NULL` result from [`CFStringGetCharactersPtr(_:)`](/documentation/CoreFoundation/CFStringGetCharactersPtr(_:)). --- 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)