---
title: "objc_duplicateClass(_:_:_:)"
framework: Objective-C Runtime
role: symbol
role_heading: Function
platforms: [iOS 2.0+, iPadOS 2.0+, Mac Catalyst 13.1+, macOS 10.5+, tvOS 9.0+, visionOS 1.0+, watchOS 1.0+]
path: "objectivec/objc_duplicateclass(_:_:_:)"
---

# objc_duplicateClass(_:_:_:)

Used by Foundation’s Key-Value Observing.

## Declaration

```swift
func objc_duplicateClass(_ original: AnyClass, _ name: UnsafePointer<CChar>, _ extraBytes: Int) -> AnyClass
```

## Discussion

Discussion Do not call this function yourself.

## See Also

### Adding Classes

- [objc_allocateClassPair(_:_:_:)](objectivec/objc_allocateclasspair(_:_:_:).md)
- [objc_disposeClassPair(_:)](objectivec/objc_disposeclasspair(_:).md)
- [objc_registerClassPair(_:)](objectivec/objc_registerclasspair(_:).md)