# kAudioUnitProperty_ClassInfo Describes the state of an audio unit. ``` var kAudioUnitProperty_ClassInfo: AudioUnitPropertyID { get } ``` ## Discussion A read/write object valid on the audio unit global scope. A macOS audio unit that supports the part scope may, in addition, support presets on that scope that apply to individual parts. When assigning a class information dictionary to an audio unit with the [`AudioUnitSetProperty(_:_:_:_:_:_:)`](/documentation/AudioToolbox/AudioUnitSetProperty(_:_:_:_:_:_:)) function, you own the reference to the dictionary and are responsible for later releasing it by calling the function. When obtaining a class information dictionary from an audio unit with the [`AudioUnitGetProperty(_:_:_:_:_:_:)`](/documentation/AudioToolbox/AudioUnitGetProperty(_:_:_:_:_:_:)) function, you also own the reference to the dictionary and are responsible for later releasing it by calling the function. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)