---
title: NewUserClient
framework: driverkit
role: symbol
role_heading: Instance Method
path: driverkit/ioservice/newuserclient
---

# NewUserClient

Requests the creation of a new user client for the service.

## Declaration

```occ
virtual kern_return_t NewUserClient(uint32_t type, IOUserClient **userClient);
```

## Parameters

- `type`: The type passed to doc://com.apple.documentation/documentation/iokit/1514515-ioserviceopen.
- `userClient`: A pointer to a variable for returning the new user client object. Upon the successful creation of the user client object, assign it to this variable.

## Return Value

Return Value kIOReturnSuccess on success, or another value if an error occurs. For a list of error codes, see Error Codes.

## Discussion

Discussion Override this method if your service supports communication though an external user client. When an app calls IOServiceOpen(_:_:_:_:) to start a new service, the system calls this method on the service passed to that function. In your implementation, call the Create method to create a new IOUserClient object for your service and return that object in the userClient parameter.

## See Also

### Creating a New Service

- [Create](driverkit/ioservice/create.md)