---
title: ControlRequestAsyncTO
framework: IOKit
role: symbol
role_heading: Instance Property
platforms: [Mac Catalyst 18.4+, macOS 10.14+]
path: iokit/iousbinterfaceinterface942/2977193-controlrequestasyncto
---

# ControlRequestAsyncTO

## Declaration

```occ
IOReturn (*ControlRequestAsyncTO)(void *self, UInt8 pipeRef, IOUSBDevRequestTO *req, IOAsyncCallback1 callback, void *refCon);
```