This function will request Serial State Notification from the attached device. If the request was accepted, transferHandle will contain a valid transfer handle, else it will contain USB_HOST_CDC_TRANSFER_HANDLE_INVALID. The completion of the request will be indicated by the USB_HOST_CDC_EVENT_SERIAL_STATE_NOTIFICATION_RECEIVED event. The transfer handle will be returned in the event.

USB_HOST_CDC_RESULT USB_HOST_CDC_SerialStateNotificationGet(
    USB_HOST_CDC_HANDLE handle, 
    USB_HOST_CDC_TRANSFER_HANDLE * transferHandle, 
    USB_CDC_SERIAL_STATE * serialState
);

The client handle should be valid.

USB_HOST_CDC_RESULT_SUCCESS - The operation was successful. 

USB_HOST_CDC_RESULT_DEVICE_UNKNOWN - The device that this request was targeted to does not exist in the system. 

USB_HOST_CDC_RESULT_BUSY - The request could not be scheduled at this time. The client should try again. 

USB_HOST_CDC_RESULT_INVALID_PARAMETER - An input parameter was NULL. 

USB_HOST_CDC_RESULT_FAILURE - An unknown failure occurred. 

USB_HOST_CDC_RESULT_HANDLE_INVALID - The client handle is not valid.

None.