---
title: CFTreeRetainCallBack
framework: Core Foundation
role: symbol
role_heading: Type Alias
path: corefoundation/cftreeretaincallback
---

# CFTreeRetainCallBack

Callback function used to retain a program-defined information pointer.

## Declaration

```swift
typealias CFTreeRetainCallBack = (UnsafeRawPointer?) -> UnsafeRawPointer?
```

## Parameters

- `info`: The program-supplied information pointer provided in a doc://com.apple.corefoundation/documentation/CoreFoundation/CFTreeContext structure.

## Return Value

Return Value The value to use whenever the information pointer is retained, which is usually the info parameter passed to this callback, but may be a different value if a different value should be used.

## See Also

### Callbacks

- [CFTreeApplierFunction](corefoundation/cftreeapplierfunction.md)
- [CFTreeCopyDescriptionCallBack](corefoundation/cftreecopydescriptioncallback.md)
- [CFTreeReleaseCallBack](corefoundation/cftreereleasecallback.md)