IWMDRMDeviceApp::QueryDeviceStatus

The QueryDeviceStatus method queries a device for its current DRM status and capabilities.

Syntax

HRESULT QueryDeviceStatus(IWMDMDevice*pDevice,DWORD*pdwStatus);

Parameters

pDevice

[in]  Pointer to an IWMDMDevice object.

pdwStatus

[out] Zero or more of the following DWORD values describing the DRM aspects of the device, combined with a bitwise OR. See Remarks.

Return Values

The method returns an HRESULT. Possible values include, but are not limited to, those in the following table.

Remarks

This method should be called before performing any restricted actions on DRM content, such as transferring DRM content to the device, or acquiring metering information. If the values retrieved by pdwStatus indicate that some action needs to be performed (such as individualization for the desktop or acquiring a clock for the device), the application should call AcquireDeviceData and pass the retrieved pdwStatus value from this function to the dwFlags parameter in AcquireDeviceData. If zero is returned, the device does not support Windows Media DRM 10 for Portable Devices, and no actions need be taken. See Handling Protected Content in the Application for more information.

Example Code

The following C++ code example creates a WMDRMDeviceApp object, verifies that the device is a Windows Media DRM 10 device, that its clock is accurate, and then requests the metering data.

HRESULT hr = S_OK;
// Create the WMDRMDeviceApp object.
CComPtr<IWMDRMDeviceApp> pDRM;
hr = pDRM.CoCreateInstance(CLSID_WMDRMDeviceApp, 0, CLSCTX_ALL);

// Find out first if the device is a WMDRM 10 device, and if it requires
// any clock updates.
DWORD status = 0;
hr = pDRM->QueryDeviceStatus(pDevice, &status);

if (!(WMDRM_DEVICE_ISWMDRM & status)) // Device is not WMDRM 10. Nothing can be updated,
    return E_FAIL;                   // and metering cannot be performed.
else if (status & WMDRM_DEVICE_REVOKED) // Device is revoked.
    return E_FAIL;
else if (status & WMDRM_DEVICE_NEEDCLOCK || 
    status & WMDRM_CLIENT_NEEDINDIV ||
    status & WMDRM_DEVICE_REFRESHCLOCK)
{
    // Need to update device clock. 
    // Using custom function, which is synchronous.
    hr = myAcquireDeviceData(pDRM, pDevice, this, status, &result);
    if (hr != S_OK || result != 0)    // Couldn't perform the updates.
        return E_FAIL;    
}

Requirements

Header: Requires both WMDRMDeviceApp.h and wmdrmdeviceapp_i.c (built from WMDRMDeviceApp.idl).

Library: mssachlp.lib

See Also

• Handling Protected Content in the Application
• IWMDRMDeviceApp Interface
• IWMDRMDeviceApp2::QueryDeviceStatus2