---
title: CFDictionaryApplierFunction
framework: corefoundation
role: symbol
role_heading: Type Alias
path: corefoundation/cfdictionaryapplierfunction
---

# CFDictionaryApplierFunction

Prototype of a callback function that may be applied to every key-value pair in a dictionary.

## Declaration

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

## Parameters

- `key`: The key associated with the current key-value pair.
- `value`: The value associated with the current key-value pair.
- `context`: The program-defined context parameter given to the apply function.

## Discussion

Discussion This callback is passed to the CFDictionaryApplyFunction(_:_:_:) function which iterates over the key-value pairs in a dictionary and applies the behavior defined in the applier function to each key-value pair in a dictionary.

## See Also

### Callbacks

- [CFDictionaryCopyDescriptionCallBack](corefoundation/cfdictionarycopydescriptioncallback.md)
- [CFDictionaryEqualCallBack](corefoundation/cfdictionaryequalcallback.md)
- [CFDictionaryHashCallBack](corefoundation/cfdictionaryhashcallback.md)
- [CFDictionaryReleaseCallBack](corefoundation/cfdictionaryreleasecallback.md)
- [CFDictionaryRetainCallBack](corefoundation/cfdictionaryretaincallback.md)