---
title: Invalid String Encoding Flag
framework: corefoundation
role: collectionGroup
role_heading: API Collection
path: corefoundation/invalid-string-encoding-flag
---

# Invalid String Encoding Flag

Special value returned from functions to indicate a string encoding that is not supported or recognized by CFString.

## Topics

### Constants

- [kCFStringEncodingInvalidId](corefoundation/kcfstringencodinginvalidid.md)

## See Also

### Constants

- [String Comparison Flags](corefoundation/string-comparison-flags.md)
- [CFStringBuiltInEncodings](corefoundation/cfstringbuiltinencodings.md)
- [External String Encodings](corefoundation/external-string-encodings.md)