---
title: soOutputToExtAudioFile
framework: applicationservices
role: symbol
role_heading: Global Variable
path: applicationservices/sooutputtoextaudiofile
---

# soOutputToExtAudioFile

Pass an ExtAudioFileRef in the speechInfo parameter to write to this file, or NULL to generate sound.

## Declaration

```swift
var soOutputToExtAudioFile: OSType { get }
```

## Discussion

Discussion Note that the Speech Synthesis Manager may alter the kExtAudioFileProperty_ClientDataFormat and kExtAudioFileProperty_ClientChannelLayout properties of the extended audio file object. The caller is responsible for closing the extended audio file object after the Speech Synthesis Manager is finished with it. This selector works with the SetSpeechInfo function.