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# uid

A system-assigned unique identifier (UID) for the port.

```
var uid: String { get }
```

## Discussion

The value of this property matches that of the [`owningPortUID`](/documentation/AVFAudio/AVAudioSessionChannelDescription/owningPortUID) property of every [`AVAudioSessionChannelDescription`](/documentation/AVFAudio/AVAudioSessionChannelDescription) object in the port’s [`channels`](/documentation/AVFAudio/AVAudioSessionPortDescription/channels) array.

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