---
title: soSynthExtension
framework: Application Services
role: symbol
role_heading: Enumeration Case
platforms: [macOS 10.0+]
path: applicationservices/1552228-speech-channel_information_constants/sosynthextension
---

# soSynthExtension

## Declaration

```occ
soSynthExtension = 'xtnd'
```

## Discussion

Get or set synthesizer-specific informationor settings. The `speechInfo` parameteris a pointer to a speech extension data structure, described in [SpeechXtndData](../speechxtnddata.md). Yourapplication should set the `synthCreator` fieldof this structure before calling `GetSpeechInfo` or `SetSpeechInfo`.Ordinarily, your application must pass additional information tothe synthesizer in the `synthData` field.

This selector works with both the `GetSpeechInfo` and `SetSpeechInfo` functions.