ISoftHIDProtocolXlator::WriteReportDescriptor Method

项目
09/21/2010

The WriteReportDescriptor method sets the report descriptor for the device.

Syntax

HRESULT WriteReportDescriptor(
  [in]  SAFEARRAY psaReportDescriptor
);

Parameters

psaReportDescriptor [in]
A pointer to SAFEARRAY of unsigned char values that contain raw report descriptor data. The caller can free this array after WriteReportDescriptor returns.

Return Value

WriteReportDescriptor returns S_OK if the operation succeeds. This method can return other standard COM return values.

Remarks

The WriteReportDescriptor method stores the report descriptor and returns it to the host in response to other GET_DESCRIPTOR requests for the report descriptor that are sent to the control endpoint for the device.

The following C++ code example shows you how to call WriteReportDescriptor.

HRESULT WriteReportDescriptor
(
 ISoftHIDProtocolXlator *piSoftHIDProtocolXlator,
    BYTE                   *pbDescriptor,
    unsigned int cbDescriptor
)
{
    HRESULT     hr            = S_OK;
    SAFEARRAY  *psaDescriptor = NULL;
    BYTE HUGEP *pbArrayData   = NULL;

 psaDescriptor = ::SafeArrayCreateVector(VT_UI1, 0, cbDescriptor);
    if (SUCCEEDED(hr))
    {
        hr = ::SafeArrayAccessData(psaDescriptor, &pbArrayData);
        if (SUCCEEDED(hr))
        {
            ::memcpy(pbArrayData, pbDescriptor, cbDescriptor);
            hr = ::SafeArrayUnaccessData(psaDescriptor);
            if (SUCCEEDED(hr))
            {
                hr = piSoftHIDProtocolXlator->WriteReportDescriptor(psaDescriptor);
            }
        }
        (void)::SafeArrayDestroy(psaDescriptor);
    }
}

Requirements

Header

SoftHIDUSBif.h