---
title: CFBagApplierFunction
framework: corefoundation
role: symbol
role_heading: Type Alias
path: corefoundation/cfbagapplierfunction
---

# CFBagApplierFunction

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

## Declaration

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

## Parameters

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

## Discussion

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

## See Also

### Callbacks

- [CFBagCopyDescriptionCallBack](corefoundation/cfbagcopydescriptioncallback.md)
- [CFBagEqualCallBack](corefoundation/cfbagequalcallback.md)
- [CFBagHashCallBack](corefoundation/cfbaghashcallback.md)
- [CFBagReleaseCallBack](corefoundation/cfbagreleasecallback.md)
- [CFBagRetainCallBack](corefoundation/cfbagretaincallback.md)