---
title: IOUSBHostCompletionHandler
framework: iousbhost
role: symbol
role_heading: Type Alias
path: iousbhost/iousbhostcompletionhandler
---

# IOUSBHostCompletionHandler

The completion handler for asynchronous control, bulk, and interrupt transfers.

## Declaration

```swift
typealias IOUSBHostCompletionHandler = (IOReturn, Int) -> Void
```

## Parameters

- `status`: The result for the transfer.
- `bytesTransferred`: The number of bytes the request transferred.