# init(bytesNoCopy:length:encoding:freeWhenDone:) Returns an initialized `NSString` object that contains a given number of bytes from a given buffer of bytes interpreted in a given encoding, and optionally frees the buffer. ``` convenience init?(bytesNoCopy bytes: UnsafeMutableRawPointer, length len: Int, encoding: UInt, freeWhenDone freeBuffer: Bool) ``` ## Parameters `bytes` A buffer of bytes interpreted in the encoding specified by `encoding`. `len` The number of bytes to use from `bytes`. `encoding` The character encoding of `bytes`. For possible values, see [`NSStringEncoding`](/documentation/Foundation/NSStringEncoding). `freeBuffer` If , the receiver releases the memory with `free()` when it no longer needs the data; if it won’t. ## Return Value An initialized `NSString` object containing `length` bytes from `bytes` interpreted using the encoding `encoding`. The returned object may be different from the original receiver. ## Discussion If an error occurs during the creation of the string, then `bytes` isn’t freed even if `flag` is . In this case, the caller is responsible for freeing the buffer. This allows the caller to continue trying to create a string with the buffer, without having the buffer deallocated. --- 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)