---
title: CLanguageStandard.iso9899_1999
framework: packagedescription
role: symbol
role_heading: Case
path: packagedescription/clanguagestandard/iso9899_1999
---

# CLanguageStandard.iso9899_1999

The identifier for the ISO C 1999 language standard.

## Declaration

```swift
case iso9899_1999
```

## See Also

### Enumeration Cases

- [CLanguageStandard.c11](packagedescription/clanguagestandard/c11.md)
- [CLanguageStandard.c17](packagedescription/clanguagestandard/c17.md)
- [CLanguageStandard.c18](packagedescription/clanguagestandard/c18.md)
- [CLanguageStandard.c2x](packagedescription/clanguagestandard/c2x.md)
- [CLanguageStandard.c89](packagedescription/clanguagestandard/c89.md)
- [CLanguageStandard.c90](packagedescription/clanguagestandard/c90.md)
- [CLanguageStandard.c99](packagedescription/clanguagestandard/c99.md)
- [CLanguageStandard.gnu11](packagedescription/clanguagestandard/gnu11.md)
- [CLanguageStandard.gnu17](packagedescription/clanguagestandard/gnu17.md)
- [CLanguageStandard.gnu18](packagedescription/clanguagestandard/gnu18.md)
- [CLanguageStandard.gnu2x](packagedescription/clanguagestandard/gnu2x.md)
- [CLanguageStandard.gnu89](packagedescription/clanguagestandard/gnu89.md)
- [CLanguageStandard.gnu90](packagedescription/clanguagestandard/gnu90.md)
- [CLanguageStandard.gnu99](packagedescription/clanguagestandard/gnu99.md)
- [CLanguageStandard.iso9899_1990](packagedescription/clanguagestandard/iso9899_1990.md)