---
title: CFSetApplierFunction
framework: corefoundation
role: symbol
role_heading: Type Alias
path: corefoundation/cfsetapplierfunction
---

# CFSetApplierFunction

Prototype of a callback function that may be applied to every value in a set.

## Declaration

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

## Parameters

- `value`: The current value in a set.
- `context`: The program-defined context parameter given to the apply function.

## Discussion

Discussion This callback is passed to the CFSetApplyFunction(_:_:_:) function which iterates over the values in a set and applies the behavior defined in the applier function to each value in a set.

## See Also

### Callbacks

- [CFSetCopyDescriptionCallBack](corefoundation/cfsetcopydescriptioncallback.md)
- [CFSetEqualCallBack](corefoundation/cfsetequalcallback.md)
- [CFSetHashCallBack](corefoundation/cfsethashcallback.md)
- [CFSetReleaseCallBack](corefoundation/cfsetreleasecallback.md)
- [CFSetRetainCallBack](corefoundation/cfsetretaincallback.md)