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# NSFileHandleDataAvailable

Posted when the file handle determines that data is currently available for reading in a file or at a communications channel.

```
static let NSFileHandleDataAvailable: NSNotification.Name
```

## Discussion

The observers can then issue the appropriate messages to begin reading the data. To cause the posting of this notification, you must send either [`waitForDataInBackgroundAndNotify()`](/documentation/Foundation/FileHandle/waitForDataInBackgroundAndNotify()) or [`waitForDataInBackgroundAndNotify(forModes:)`](/documentation/Foundation/FileHandle/waitForDataInBackgroundAndNotify(forModes:)) to an appropriate `NSFileHandle` object.

The notification object is the `NSFileHandle` object that sent the notification. This notification doesn’t contain a `userInfo` dictionary.

---

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