# CFURLCreateCopyAppendingPathComponent(_:_:_:_:) Creates a copy of a given URL and appends a path component. ``` func CFURLCreateCopyAppendingPathComponent(_ allocator: CFAllocator!, _ url: CFURL!, _ pathComponent: CFString!, _ isDirectory: Bool) -> CFURL! ``` ## Parameters `allocator` The allocator to use to allocate memory for the new `CFURL` object. Pass `NULL` or [`kCFAllocatorDefault`](/documentation/CoreFoundation/kCFAllocatorDefault) to use the current default allocator. `url` The `CFURL` object to which to append a path component. `pathComponent` The path component to append to `url`. `isDirectory` A Boolean value that specifies whether the string is treated as a directory path when resolving against relative path components. Pass `true` if the new component indicates a directory, `false` otherwise. ## Return Value A copy of `url` appended with `pathComponent`. Ownership follows the create rule. See [The Create Rule](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html#//apple_ref/doc/uid/20001148-103029). ## Discussion The `isDirectory` argument specifies whether or not the new path component points to a file or a to directory. Note that the URL syntax for a directory and for a file at otherwise the same location are slightly different—directory URLs must end in “/”. If you have the URL `http://www.apple.com/foo/` and you append the path component `bar`, then if `isDirectory` is then the resulting URL is `http://www.apple.com/foo/bar/`, whereas if `isDirectory` is then the resulting URL is `http://www.apple.com/foo/bar`. This difference is particularly important if you resolve another URL against this new URL. `file.html` relative to `http://www.apple.com/foo/bar` is `http://www.apple.com/foo/file.html`, whereas `file.html` relative to `http://www.apple.com/foo/bar/` is `http://www.apple.com/foo/bar/file.html`. --- 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)