---
title: DeviceRequestAsyncTO
framework: IOKit
role: symbol
role_heading: Instance Property
platforms: [Mac Catalyst 18.4+, macOS 10.14+]
path: iokit/iousbdeviceinterface942/2977141-devicerequestasyncto
---

# DeviceRequestAsyncTO

## Declaration

```occ
IOReturn (*DeviceRequestAsyncTO)(void *self, IOUSBDevRequestTO *req, IOAsyncCallback1 callback, void *refCon);
```