---
title: "CFTreeApplyFunctionToChildren(_:_:_:)"
framework: Core Foundation
role: symbol
role_heading: Function
path: "corefoundation/cftreeapplyfunctiontochildren(_:_:_:)"
---

# CFTreeApplyFunctionToChildren(_:_:_:)

Calls a function once for each immediate child of a tree.

## Declaration

```swift
func CFTreeApplyFunctionToChildren(_ tree: CFTree!, _ applier: ((UnsafeRawPointer?, UnsafeMutableRawPointer?) -> Void)!, _ context: UnsafeMutableRawPointer!)
```

## Parameters

- `tree`: The tree to operate upon.
- `applier`: The callback function to call once for each child in tree. The function must be able to apply to all the values in the tree.
- `context`: A pointer-sized program-defined value that is passed to the applier function, but is otherwise unused by this function.

## Discussion

Discussion Note that the applier only operates one level deep—it does not operate on descendants further removed than the immediate children of a tree. If the tree is mutable, it is unsafe for the applied function to change the contents of the tree.