---
title: PropertiesChanged
framework: audiodriverkit
role: symbol
role_heading: Instance Method
path: audiodriverkit/iouseraudiodriver/propertieschanged
---

# PropertiesChanged

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

## Declaration

```occ
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 doc://com.apple.audiodriverkit/documentation/AudioDriverKit/AudioDriverKit/IOUserAudioObjectPropertySelector instances for the changed properties.
- `in_num_properties`: The number of elements in the in_properties array.

## Return Value

Return Value kIOReturnSuccess on success, or another value if an error occurs. For a list of error codes, see Error Codes.

## Discussion

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

## See Also

### Communicating with the Host

- [IOUserAudioObjectPropertySelector](audiodriverkit/audiodriverkit/iouseraudioobjectpropertyselector.md)