# init(unchecked:isKnownASCII:) Creates a UTF8Span, bypassing safety and security checks. The caller must guarantee that `codeUnits` contains validly-encoded UTF-8, or else undefined behavior may result upon use. If `isKnownASCII: true is passed`, the contents must be ASCII, or else undefined behavior may result upon use. ``` init(unchecked codeUnits: Span, isKnownASCII: Bool = false) ``` --- 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)