---
title: checkForASCII()
framework: swift
role: symbol
role_heading: Instance Method
path: swift/utf8span/checkforascii()
---

# checkForASCII()

Do a scan checking for whether the contents are all-ASCII.

## Declaration

```swift
mutating func checkForASCII() -> Bool
```

## Discussion

Discussion Updates the isKnownASCII bit if contents are all-ASCII. note: O(n)