---
title: Open
framework: hiddriverkit
role: symbol
role_heading: Instance Method
path: hiddriverkit/iohidinterface/open
---

# Open

Opens a session to the device and begins the delivery of input reports.

## Declaration

```occ
virtual kern_return_t Open(IOService *forClient, IOOptionBits options, OSAction *action);
```

## Parameters

- `forClient`: The client that opened the interface.
- `options`: Options to use when opening the session. Specify 0 for no options.
- `action`: The OSAction object that handles the asynchronous report callback. The action’s callback must conform to the doc://com.apple.hiddriverkit/documentation/HIDDriverKit/IOHIDInterface/ReportAvailable method.

## Return Value

Return Value kIOReturnSuccess on success, or another value if an error occurs. See Error Codes.

## See Also

### Managing the Session

- [Close](hiddriverkit/iohidinterface/close.md)