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  "framework" : "AudioDriverKit",
  "identifier" : "/documentation/AudioDriverKit/IOUserAudioDriver/PropertiesChanged",
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  "role" : "Instance Method",
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  "title" : "PropertiesChanged"
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# PropertiesChanged

Informs the host when the state of an object in the driver changes.

```
kern_return_t PropertiesChanged(IOUserAudioObjectID in_object_id, IOUserAudioObjectPropertySelector *in_properties, uint32_t in_num_properties);
```

## Parameters

`in_object_id`

The identifier of the object whose properties changed.

`in_properties`

An array of [`IOUserAudioObjectPropertySelector`](/documentation/AudioDriverKit/AudioDriverKit/IOUserAudioObjectPropertySelector) instances for the changed properties.

`in_num_properties`

The number of elements in the `in_properties` array.

## Return Value

<doc://com.apple.documentation/documentation/DriverKit/kIOReturnSuccess> on success, or another value if an error occurs. For a list of error codes, see <doc://com.apple.documentation/documentation/DriverKit/error-codes>.

## Discussion

For device objects, only use this method for state changes that don’t affect IO or the structure of the device.

---

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