# CFStringGetFileSystemRepresentation(_:_:_:) Extracts the contents of a string as a `NULL`-terminated 8-bit string appropriate for passing to POSIX APIs. ``` func CFStringGetFileSystemRepresentation(_ string: CFString!, _ buffer: UnsafeMutablePointer!, _ maxBufLen: CFIndex) -> Bool ``` ## Parameters `string` The string to convert. `buffer` The C string buffer into which to copy the string. The buffer must be at least `maxBufLen` bytes in length. On return, the buffer contains the converted characters. `maxBufLen` The maximum length of the buffer. ## Return Value `true` if the string is correctly converted; `false` if the conversion fails, or the results don’t fit into the buffer. ## Discussion You can use [`CFStringGetMaximumSizeOfFileSystemRepresentation(_:)`](/documentation/CoreFoundation/CFStringGetMaximumSizeOfFileSystemRepresentation(_:)) if you want to make sure the buffer is of sufficient length. --- 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)