# init(CStringNoCopy:length:freeWhenDone:) Initializes the receiver, a newly allocated `NSString` object, by converting the data in a given C-string from the default C-string encoding into the Unicode character encoding. ``` convenience init?(CStringNoCopy bytes: UnsafeMutablePointer, length: Int, freeWhenDone freeBuffer: Bool) ``` ## Discussion This method converts `length` * `sizeof(char)` bytes from `cString` and doesn’t stop short at a zero character. `cString` must contain data in the default C-string encoding and may not be `NULL`. The receiver becomes the owner of `cString`; if `flag` is it will free the memory when it no longer needs it, but if `flag` is it won’t. Returns an initialized object, which might be different from the original receiver. You can use this method to create an immutable string from an immutable (`const char *`) C-string buffer. If you receive a warning message, you can disregard it; its purpose is simply to warn you that the C string passed as the method’s first argument may be modified. If you make certain the `freeWhenDone` argument to `initWithStringNoCopy` is , the C string passed as the method’s first argument cannot be modified, so you can safely use `initWithStringNoCopy` to create an immutable string from an immutable (`const char *`) C-string buffer. ## See Also --- 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)