# defaultCStringEncoding Returns the C-string encoding assumed for any method accepting a C string as an argument. ``` class var defaultCStringEncoding: UInt { get } ``` ## Return Value The C-string encoding assumed for any method accepting a C string as an argument. ## Discussion This method returns a user-dependent encoding who value is derived from user’s default language and potentially other factors. You might sometimes need to use this encoding when interpreting user documents with unknown encodings, in the absence of other hints, but in general this encoding should be used rarely, if at all. Note that some potential values might result in unexpected encoding conversions of even fairly straightforward `NSString` content—for example, punctuation characters with a bidirectional encoding. Methods that accept a C string as an argument use `...CString...` in the keywords for such arguments: for example, [`string(withCString:)`](/documentation/Foundation/NSString/string(withCString:))—note, though, that these are deprecated. The default C-string encoding is determined from system information and can’t be changed programmatically for an individual process. See [`NSStringEncoding`](/documentation/Foundation/NSStringEncoding) for a full list of supported encodings. --- 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)