---
title: AudioStreamPropertyListenerProc
framework: coreaudio
role: symbol
role_heading: Type Alias
path: coreaudio/audiostreampropertylistenerproc
---

# AudioStreamPropertyListenerProc

## Declaration

```swift
typealias AudioStreamPropertyListenerProc = (AudioStreamID, UInt32, AudioDevicePropertyID, UnsafeMutableRawPointer?) -> OSStatus
```

## Parameters

- `inStream`: The AudioStream whose property has changed.
- `inChannel`: The channel of the property that changed where 0 is the main channel.
- `inPropertyID`: The AudioDevicePropertyID of the property that changed.
- `inClientData`: A pointer to client data established when the listener proc was registered with the object.

## Return Value

Return Value The return value is currently unused and should always be 0.

## Discussion

Discussion Clients register an AudioStreamPropertyListenerProc with the AudioStream object in order to receive notifications when the properties of the object change. Note that the same functionality is provided by AudioObjectPropertyListenerProc.

## See Also

### Data Types

- [AudioClassID](coreaudio/audioclassid.md)
- [AudioDeviceID](coreaudio/audiodeviceid.md)
- [AudioDeviceIOBlock](coreaudio/audiodeviceioblock.md)
- [AudioDeviceIOProc](coreaudio/audiodeviceioproc.md)
- [AudioDeviceIOProcID](coreaudio/audiodeviceioprocid.md)
- [AudioDevicePropertyID](coreaudio/audiodevicepropertyid.md)
- [AudioDevicePropertyListenerProc](coreaudio/audiodevicepropertylistenerproc.md)
- [AudioHardwarePropertyID](coreaudio/audiohardwarepropertyid.md)
- [AudioHardwarePropertyListenerProc](coreaudio/audiohardwarepropertylistenerproc.md)
- [AudioObjectID](coreaudio/audioobjectid.md)
- [AudioObjectPropertyElement](coreaudio/audioobjectpropertyelement.md)
- [AudioObjectPropertyListenerBlock](coreaudio/audioobjectpropertylistenerblock.md)
- [AudioObjectPropertyListenerProc](coreaudio/audioobjectpropertylistenerproc.md)
- [AudioObjectPropertyScope](coreaudio/audioobjectpropertyscope.md)
- [AudioObjectPropertySelector](coreaudio/audioobjectpropertyselector.md)