---
title: "init(unchecked:isKnownASCII:)"
framework: swift
role: symbol
role_heading: Initializer
path: "swift/utf8span/init(unchecked:isknownascii:)"
---

# 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.

## Declaration

```swift
init(unchecked codeUnits: Span<UInt8>, isKnownASCII: Bool = false)
```