---
title: release
framework: corefoundation
role: symbol
role_heading: Instance Property
path: corefoundation/cfsetcallbacks/release
---

# release

The callback used to release values as they are removed from the collection. If NULL, values are not released. See CFSetReleaseCallBack for a description of this callback.

## Declaration

```swift
var release: CFSetReleaseCallBack!
```