# CFStringCreateWithFormat Creates an immutable string from a formatted string and a variable number of arguments. ``` extern CFStringRefCFStringCreateWithFormat(CFAllocatorRef alloc, CFDictionaryRef formatOptions, CFStringRef format, ...); ``` ## 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. `formatOptions` A CFDictionary object containing formatting options for the string (such as the thousand-separator character, which is dependent on locale). Currently, these options are an unimplemented feature. `format` The formatted string with `printf`-style specifiers followed by the variable argument list of values. For information on supported specifiers, see [String Format Specifiers](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFStrings/formatSpecifiers.html#//apple_ref/doc/uid/TP40004265). ## Return Value An immutable string, 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 --- 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)