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# CLanguageStandard

The supported C language standard you use to compile C sources in the
package.

```
enum CLanguageStandard
```

## Topics

### Enumeration Cases

[`case c11`](/documentation/PackageDescription/CLanguageStandard/c11)

The identifier for the ISO C 2011 language standard.

[`case c17`](/documentation/PackageDescription/CLanguageStandard/c17)

The identifier for the ISO C 2017 language stadard.

[`case c18`](/documentation/PackageDescription/CLanguageStandard/c18)

The identifier for the ISO C 2017 language standard.

[`case c2x`](/documentation/PackageDescription/CLanguageStandard/c2x)

The identifier for the ISO C2x draft language standard.

[`case c89`](/documentation/PackageDescription/CLanguageStandard/c89)

The identifier for the ISO C 1989 language standard.

[`case c90`](/documentation/PackageDescription/CLanguageStandard/c90)

The identifier for the ISO C 1990 language standard.

[`case c99`](/documentation/PackageDescription/CLanguageStandard/c99)

The identifier for the ISO C 1999 language standard.

[`case gnu11`](/documentation/PackageDescription/CLanguageStandard/gnu11)

The identifier for the ISO C 2011 language standard with GNU extensions.

[`case gnu17`](/documentation/PackageDescription/CLanguageStandard/gnu17)

The identifier for the ISO C 2017 language standard with GNU extensions.

[`case gnu18`](/documentation/PackageDescription/CLanguageStandard/gnu18)

The identifier for the ISO C 2017 language standard with GNU extensions.

[`case gnu2x`](/documentation/PackageDescription/CLanguageStandard/gnu2x)

The identifier for the ISO C2x draft language standard with GNU extensions.

[`case gnu89`](/documentation/PackageDescription/CLanguageStandard/gnu89)

The identifier for the ISO C 1990 language standard with GNU extensions.

[`case gnu90`](/documentation/PackageDescription/CLanguageStandard/gnu90)

The identifier for the ISO C 1990 language standard with GNU extensions.

[`case gnu99`](/documentation/PackageDescription/CLanguageStandard/gnu99)

The identifier for the ISO C 1999 language standard with GNU extensions.

[`case iso9899_1990`](/documentation/PackageDescription/CLanguageStandard/iso9899_1990)

The identifier for the ISO C 1990 language standard.

[`case iso9899_199409`](/documentation/PackageDescription/CLanguageStandard/iso9899_199409)

The identifier for the ISO C 1990 language standard with amendment 1.

[`case iso9899_1999`](/documentation/PackageDescription/CLanguageStandard/iso9899_1999)

The identifier for the ISO C 1999 language standard.

[`case iso9899_2011`](/documentation/PackageDescription/CLanguageStandard/iso9899_2011)

The identifier for the ISO C 2011 language standard.

[`case iso9899_2017`](/documentation/PackageDescription/CLanguageStandard/iso9899_2017)

The identifier for the ISO C 2017 language standard.

[`case iso9899_2018`](/documentation/PackageDescription/CLanguageStandard/iso9899_2018)

The identifier for the ISO C 2017 language standard.

### Hashing

### Operator Functions

### Creating a Value

## Relationships

### Conforms To

[`Escapable`](/documentation/Swift/Escapable)

[`Equatable`](/documentation/Swift/Equatable)

[`Copyable`](/documentation/Swift/Copyable)

[`Hashable`](/documentation/Swift/Hashable)

[`RawRepresentable`](/documentation/Swift/RawRepresentable)

---

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