---
title: AudioUnitElement
framework: audiotoolbox
role: symbol
role_heading: Type Alias
path: audiotoolbox/audiounitelement
---

# AudioUnitElement

The data type for an audio unit element identifier.

## Declaration

```swift
typealias AudioUnitElement = UInt32
```

## Discussion

Discussion An audio unit element is a discrete programmatic context that is nested within an audio unit scope (see AudioUnitScope). In the context of input and output scopes, elements serve as programmatic analogs of physical signal buses in hardware audio devices. Because of this analogy, the term “bus” is a common synonym for “element.” Elements are zero indexed. The Global scope always has exactly one element—element 0.

## See Also

### Audio Unit Types

- [ScheduledAudioFileRegion](audiotoolbox/scheduledaudiofileregion.md)
- [ScheduledAudioSlice](audiotoolbox/scheduledaudioslice.md)
- [ScheduledAudioFileRegionCompletionProc](audiotoolbox/scheduledaudiofileregioncompletionproc.md)
- [ScheduledAudioSliceCompletionProc](audiotoolbox/scheduledaudioslicecompletionproc.md)
- [MIDIChannelNumber](audiotoolbox/midichannelnumber.md)
- [AUAudioObjectID](audiotoolbox/auaudioobjectid.md)
- [AUMIDICIProfileChangedBlock](audiotoolbox/aumidiciprofilechangedblock.md)
- [AUAudioChannelCount](audiotoolbox/auaudiochannelcount.md)
- [AUAudioFrameCount](audiotoolbox/auaudioframecount.md)
- [AUAudioUnitStatus](audiotoolbox/auaudiounitstatus.md)
- [AUEventListenerProc](audiotoolbox/aueventlistenerproc.md)
- [AUEventListenerRef](audiotoolbox/aueventlistenerref.md)
- [AUEventSampleTime](audiotoolbox/aueventsampletime.md)
- [AUImplementorValueObserver](audiotoolbox/auimplementorvalueobserver.md)
- [AUImplementorValueProvider](audiotoolbox/auimplementorvalueprovider.md)