ISoftUSBEndpointEvents::OnDeviceRequestComplete Method

项目
09/21/2010

The OnDeviceRequestComplete event enables the device simulator to determine the final status of a request. This event is fired for control endpoints when the status phase transaction is received for a device request.

Syntax

HRESULT OnDeviceRequestComplete(
  [in]   ULONG RequestHandle,
  [out]  BYTE *pbFinalRequestStatus
);

Parameters

RequestHandle [in]
A handle that defines the request.
pbFinalRequestStatus [out]
The status of the request, which is returned to the host controller.

Return Value

OnDeviceRequestComplete returns an HRESULT value.

Remarks

The OnDeviceRequestComplete event is fired to complete the transaction that is associated with a SETUP transfer from the OnDeviceRequest event. This event gives the device the opportunity to update the final status of the transfer.

The following C++ code example shows how to handle the completion of a device request.

STDMETHODIMP CSoftUSBEndpointEvent::OnDeviceRequestComplete(
                                        __in  ULONG_PTR RequestHandle,
                                        __out BYTE *pbFinalRequestStatus)
{

     // Set the return error code in case the device is not handling requests
    HRESULT hr = E_NOINTERFACE;

    // Verify the incoming variables and initialize them
    if (NULL == pbFinalRequestStatus)
    {
      hr = E_POINTER;
      goto Exit;
    }
    *pbFinalRequestStatus = USB_STALL;

    if (g_fHandleDeviceRequests)
    {
        hr = S_OK;
        // If this request is the request that the device just handled, ACK the return
        // Otherwise NAK the return so the host will retry
        if (RequestHandle != m_ulDescriptorHandle)
        {
            *pbFinalRequestStatus = USB_NAK;
        }
        else
        {
            *pbFinalRequestStatus = USB_ACK;
            m_ulDescriptorHandle = 0;
        }
    }  
Exit:
    return hr;
}

Requirements

Header

SoftUSBif.h

通过