---
title: IOUSBHostIsochronousCompletionHandler
framework: iousbhost
role: symbol
role_heading: Type Alias
path: iousbhost/iousbhostisochronouscompletionhandler
---

# IOUSBHostIsochronousCompletionHandler

A completion handler for asynchronous isochronous transfers.

## Declaration

```swift
typealias IOUSBHostIsochronousCompletionHandler = (IOReturn, UnsafeMutablePointer<IOUSBHostIsochronousFrame>) -> Void
```

## Parameters

- `status`: The result code for isochronous transfer.
- `frameList`: The frame list of doc://com.apple.iousbhost/documentation/IOUSBHost/IOUSBHostIsochronousFrame that doc://com.apple.iousbhost/documentation/IOUSBHost/IOUSBHostPipe/enqueueIORequest(with:frameList:frameListCount:firstFrameNumber:completionHandler:) passes.

## See Also

### Sending Isochronous I/O

- [IOUSBHostTime](iousbhost/iousbhosttime.md)
- [IOUSBHostIsochronousFrame](iousbhost/iousbhostisochronousframe.md)
- [enqueueIORequest(with:frameList:frameListCount:firstFrameNumber:completionHandler:)](iousbhost/iousbhostpipe/enqueueiorequest(with:framelist:framelistcount:firstframenumber:completionhandler:).md)
- [sendIORequest(with:frameList:frameListCount:firstFrameNumber:)](iousbhost/iousbhostpipe/sendiorequest(with:framelist:framelistcount:firstframenumber:).md)