---
title: CFTreeApplierFunction
framework: Core Foundation
role: symbol
role_heading: Type Alias
path: corefoundation/cftreeapplierfunction
---

# CFTreeApplierFunction

Type of the callback function used by the CFTree apply function.

## Declaration

```swift
typealias CFTreeApplierFunction = (UnsafeRawPointer?, UnsafeMutableRawPointer?) -> Void
```

## Parameters

- `value`: The current child of a tree that is being iterated.
- `context`: The program-defined context parameter that was passed to the applier function.

## Discussion

Discussion This callback is used by the CFTreeApplyFunctionToChildren(_:_:_:) applier function.

## See Also

### Callbacks

- [CFTreeCopyDescriptionCallBack](corefoundation/cftreecopydescriptioncallback.md)
- [CFTreeReleaseCallBack](corefoundation/cftreereleasecallback.md)
- [CFTreeRetainCallBack](corefoundation/cftreeretaincallback.md)