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# AudioHardwarePropertyListenerProc

```
typealias AudioHardwarePropertyListenerProc = (AudioHardwarePropertyID, UnsafeMutableRawPointer?) -> OSStatus
```

## Parameters

`inPropertyID`

The AudioHardwarePropertyID of the property that changed.

`inClientData`

A pointer to client data established when the listener proc was registered
with the AudioSystemObject.

## Return Value

The return value is currently unused and should always be 0.

## Discussion

\abstract Clients register an AudioHardwarePropertyListenerProc with the AudioSystemObject
in order to receive notifications when the properties of the object change.
\discussion Note that the same functionality is provided by AudioObjectPropertyListenerProc.

---

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