# CFStringAppendCString(_:_:_:) Appends a C string to the character contents of a CFMutableString object. ``` func CFStringAppendCString(_ theString: CFMutableString!, _ cStr: UnsafePointer!, _ encoding: CFStringEncoding) ``` ## Parameters `theString` The string to which the characters from `cStr` are appended. If this value is not a CFMutableString object, an assertion is raised. `cStr` A pointer to a C string buffer. `encoding` The encoding of the characters in `cStr`. ## 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)