---
title: kAudioUnitProperty_ClassInfo
framework: audiotoolbox
role: symbol
role_heading: Global Variable
path: audiotoolbox/kaudiounitproperty_classinfo
---

# kAudioUnitProperty_ClassInfo

Describes the state of an audio unit.

## Declaration

```swift
var kAudioUnitProperty_ClassInfo: AudioUnitPropertyID { get }
```

## Discussion

Discussion A read/write CFDictionary 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(_:_:_:_:_:_:) function, you own the reference to the dictionary and are responsible for later releasing it by calling the CFRelease function. When obtaining a class information dictionary from an audio unit with the AudioUnitGetProperty(_:_:_:_:_:_:) function, you also own the reference to the dictionary and are responsible for later releasing it by calling the CFRelease function.

## See Also

### Properties

- [kAudioUnitProperty_ElementCount](audiotoolbox/kaudiounitproperty_elementcount.md)
- [kAudioUnitProperty_SupportedNumChannels](audiotoolbox/kaudiounitproperty_supportednumchannels.md)
- [kAudioUnitProperty_AudioChannelLayout](audiotoolbox/kaudiounitproperty_audiochannellayout.md)
- [kAudioUnitProperty_AudioUnitMIDIProtocol](audiotoolbox/kaudiounitproperty_audiounitmidiprotocol.md)
- [kAudioUnitProperty_AUHostIdentifier](audiotoolbox/kaudiounitproperty_auhostidentifier.md)
- [kAudioUnitProperty_BypassEffect](audiotoolbox/kaudiounitproperty_bypasseffect.md)
- [kAudioUnitProperty_ClassInfoFromDocument](audiotoolbox/kaudiounitproperty_classinfofromdocument.md)
- [kAudioUnitProperty_CocoaUI](audiotoolbox/kaudiounitproperty_cocoaui.md)
- [kAudioUnitProperty_ContextName](audiotoolbox/kaudiounitproperty_contextname.md)
- [kAudioUnitProperty_CPULoad](audiotoolbox/kaudiounitproperty_cpuload.md)
- [kAudioUnitProperty_DependentParameters](audiotoolbox/kaudiounitproperty_dependentparameters.md)
- [kAudioUnitProperty_ElementName](audiotoolbox/kaudiounitproperty_elementname.md)
- [kAudioUnitProperty_FactoryPresets](audiotoolbox/kaudiounitproperty_factorypresets.md)
- [kAudioUnitProperty_FastDispatch](audiotoolbox/kaudiounitproperty_fastdispatch.md)
- [kAudioUnitProperty_FrequencyResponse](audiotoolbox/kaudiounitproperty_frequencyresponse.md)