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  "identifier" : "/documentation/SerialDriverKit/IOUserSerial/Start",
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  "title" : "Start"
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# Start

Starts the current service and associates it with the specified provider.

```
virtual kern_return_t Start(IOService *provider);
```

## Parameters

`provider`

The provider object that matches the current service. Cast this object to the class you expect. The system retains this object for the duration of your `Start` method. The system continues to retain the object if your service starts successfully, releasing it only after calling your service’s [`Stop`](/documentation/SerialDriverKit/IOUserSerial/Stop) method.

## Return Value

<doc://com.apple.documentation/documentation/DriverKit/kIOReturnSuccess> on success, or another value if an error occurs. See <doc://com.apple.documentation/documentation/DriverKit/error-codes>.

## Discussion

After successfully matching the specified `provider` to your driver’s service, the system instantiates your service object and calls this method. Use this method to perform any additional configuration of your driver, and then call the <doc://com.apple.documentation/documentation/DriverKit/IOService/RegisterService> method to let the system know that your service is running. For example, you might use this method to store a reference to the specified provider object for later use. Always call `super` early in your implementation of this method.

You don’t need to open a communications channel to your device in this method. The system calls your service’s [`HwActivate`](/documentation/SerialDriverKit/IOUserSerial/HwActivate) method separately to activate your hardware.

---

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