---
title: CLanguageStandard.c90
framework: swift-package-manager
role: symbol
role_heading: Case
path: swift-package-manager/documentation/packagedescription/clanguagestandard/c90
---

# CLanguageStandard.c90

The identifier for the ISO C 1990 language standard.

## Declaration

```swift
case c90
```

## See Also

### Enumeration Cases

- [CLanguageStandard.c11](swift-package-manager/documentation/packagedescription/clanguagestandard/c11.md)
- [CLanguageStandard.c17](swift-package-manager/documentation/packagedescription/clanguagestandard/c17.md)
- [CLanguageStandard.c18](swift-package-manager/documentation/packagedescription/clanguagestandard/c18.md)
- [CLanguageStandard.c2x](swift-package-manager/documentation/packagedescription/clanguagestandard/c2x.md)
- [CLanguageStandard.c89](swift-package-manager/documentation/packagedescription/clanguagestandard/c89.md)
- [CLanguageStandard.c99](swift-package-manager/documentation/packagedescription/clanguagestandard/c99.md)
- [CLanguageStandard.gnu11](swift-package-manager/documentation/packagedescription/clanguagestandard/gnu11.md)
- [CLanguageStandard.gnu17](swift-package-manager/documentation/packagedescription/clanguagestandard/gnu17.md)
- [CLanguageStandard.gnu18](swift-package-manager/documentation/packagedescription/clanguagestandard/gnu18.md)
- [CLanguageStandard.gnu2x](swift-package-manager/documentation/packagedescription/clanguagestandard/gnu2x.md)
- [CLanguageStandard.gnu89](swift-package-manager/documentation/packagedescription/clanguagestandard/gnu89.md)
- [CLanguageStandard.gnu90](swift-package-manager/documentation/packagedescription/clanguagestandard/gnu90.md)
- [CLanguageStandard.gnu99](swift-package-manager/documentation/packagedescription/clanguagestandard/gnu99.md)
- [CLanguageStandard.iso9899_1990](swift-package-manager/documentation/packagedescription/clanguagestandard/iso9899_1990.md)
- [CLanguageStandard.iso9899_199409](swift-package-manager/documentation/packagedescription/clanguagestandard/iso9899_199409.md)