<!--
{
  "availability" : [
    "macCatalyst: -",
    "macOS: -"
  ],
  "documentType" : "symbol",
  "framework" : "CoreAudio",
  "identifier" : "/documentation/CoreAudio/AudioStreamPropertyListenerProc",
  "metadataVersion" : "0.1.0",
  "role" : "Type Alias",
  "symbol" : {
    "kind" : "Type Alias",
    "modules" : [
      "Core Audio"
    ],
    "preciseIdentifier" : "c:@T@AudioStreamPropertyListenerProc"
  },
  "title" : "AudioStreamPropertyListenerProc"
}
-->

# AudioStreamPropertyListenerProc

```
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

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

## Discussion

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

---

Copyright &copy; 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)