---
title: "AudioSessionAddPropertyListener(_:_:_:)"
framework: audiotoolbox
role: symbol
role_heading: Function
path: "audiotoolbox/audiosessionaddpropertylistener(_:_:_:)"
---

# AudioSessionAddPropertyListener(_:_:_:)

Adds a property listener callback function to your application’s audio session object.

## Declaration

```swift
func AudioSessionAddPropertyListener(_ inID: AudioSessionPropertyID, _ inProc: AudioSessionPropertyListener!, _ inClientData: UnsafeMutableRawPointer!) -> OSStatus
```

## Parameters

- `inID`: The identifier for the audio session property whose value changes you want to listen for.
- `inProc`: The name of your property listener callback function.
- `inClientData`: Data that you would like to be passed to your property listener callback.

## Return Value

Return Value A result code. See Result Codes.

## Discussion

Discussion When an audio session property value changes, and you have added a listener callback for that property, the audio session object invokes the callback. You can add exactly one listener callback for a given inID-inClientData pair. In other words, you can add more than one property listener callback function for a given audio session property, provided you pass a unique inClientData parameter value each time you add a property listener. Audio session properties are listed and described in Audio Session Property Identifiers.

## See Also

### Functions

- [AudioFileReadPackets(_:_:_:_:_:_:_:)](audiotoolbox/audiofilereadpackets(_:_:_:_:_:_:_:).md)
- [AudioComponentGetIcon(_:_:)](audiotoolbox/audiocomponentgeticon(_:).md)
- [AudioComponentGetLastActiveTime(_:)](audiotoolbox/audiocomponentgetlastactivetime(_:).md)
- [AudioHardwareServiceAddPropertyListener(_:_:_:_:)](audiotoolbox/audiohardwareserviceaddpropertylistener(_:_:_:_:).md)
- [AudioHardwareServiceGetPropertyData(_:_:_:_:_:_:)](audiotoolbox/audiohardwareservicegetpropertydata(_:_:_:_:_:_:).md)
- [AudioHardwareServiceGetPropertyDataSize(_:_:_:_:_:)](audiotoolbox/audiohardwareservicegetpropertydatasize(_:_:_:_:_:).md)
- [AudioHardwareServiceHasProperty(_:_:)](audiotoolbox/audiohardwareservicehasproperty(_:_:).md)
- [AudioHardwareServiceIsPropertySettable(_:_:_:)](audiotoolbox/audiohardwareserviceispropertysettable(_:_:_:).md)
- [AudioHardwareServiceRemovePropertyListener(_:_:_:_:)](audiotoolbox/audiohardwareserviceremovepropertylistener(_:_:_:_:).md)
- [AudioHardwareServiceSetPropertyData(_:_:_:_:_:_:)](audiotoolbox/audiohardwareservicesetpropertydata(_:_:_:_:_:_:).md)
- [AudioOutputUnitGetHostIcon(_:_:)](audiotoolbox/audiooutputunitgethosticon(_:_:).md)
- [AudioOutputUnitPublish(_:_:_:_:)](audiotoolbox/audiooutputunitpublish(_:_:_:_:).md)
- [AudioSessionGetProperty(_:_:_:)](audiotoolbox/audiosessiongetproperty(_:_:_:).md)
- [AudioSessionGetPropertySize(_:_:)](audiotoolbox/audiosessiongetpropertysize(_:_:).md)
- [AudioSessionInitialize(_:_:_:_:)](audiotoolbox/audiosessioninitialize(_:_:_:_:).md)