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# CFTreeApplierFunction

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

```
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

This callback is used by the [`CFTreeApplyFunctionToChildren(_:_:_:)`](/documentation/CoreFoundation/CFTreeApplyFunctionToChildren(_:_:_:)) applier function.

---

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