---
title: "init(midiOutputCallback:userData:)"
framework: audiotoolbox
role: symbol
role_heading: Initializer
path: "audiotoolbox/aumidioutputcallbackstruct/init(midioutputcallback:userdata:)"
---

# init(midiOutputCallback:userData:)

## Declaration

```swift
init(midiOutputCallback: AUMIDIOutputCallback, userData: UnsafeMutableRawPointer?)
```