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# CFNotificationCallback

Callback function invoked for each observer of a notification when the notification is posted.

```
typealias CFNotificationCallback = (CFNotificationCenter?, UnsafeMutableRawPointer?, CFNotificationName?, UnsafeRawPointer?, CFDictionary?) -> Void
```

## Parameters

`center`

The notification center handling the notification.

`observer`

An arbitrary value, other than `NULL`, that identifies the observer.

`name`

The name of the notification being posted.

`object`

An arbitrary value that identifies the object posting the notification. For distributed notifications, `object` is always a CFString object. This value could be `NULL`.

`userInfo`

A dictionary containing additional information regarding the notification. This value could be `NULL`.

    If the notification center is a Darwin notification center, this value must be ignored.

## Discussion

---

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