IWMDMDeviceControl::GetCapabilities (deprecated)
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This is preliminary documentation and subject to change.
This topic documents a feature of the Windows Media Device Manager SDK. We recommend that you migrate your application to use the Windows Portable Devices API. For more information, see the Windows Portable Devices SDK.
The GetCapabilities method retrieves the device capabilities to determine what operations the device can perform. The capabilities describe the methods of the device control that are supported by the media device.
Syntax
HRESULT GetCapabilities(
DWORD* pdwCapabilitiesMask
);
Parameters
pdwCapabilitiesMask
[out] Pointer to a DWORD specifying the capabilities of the device. The following flags can be returned in this variable.
| Flag | Description |
| WMDM_DEVICECAP_CANPLAY | The media device can play MP3 audio. |
| WMDM_DEVICECAP_CANSTREAMPLAY | The media device can play streaming audio directly from the host computer. |
| WMDM_DEVICECAP_CANRECORD | The media device can record audio. |
| WMDM_DEVICECAP_CANSTREAMRECORD | The media device can record streaming audio directly to the host computer. |
| WMDM_DEVICECAP_CANPAUSE | The media device can pause during play or record operations. |
| WMDM_DEVICECAP_CANRESUME | The media device can resume an operation that was paused. |
| WMDM_DEVICECAP_CANSTOP | The media device can stop playing before the end of a file. |
| WMDM_DEVICECAP_CANSEEK | The media device can seek to a position other than the beginning of a file. |
| WMDM_DEVICECAP_HASSECURECLOCK | The media device has a secure clock. |
Return Values
The method returns an HRESULT. Possible values include, but are not limited to, those in the following table.
| Return code | Description |
| S_OK | The method succeeded. |
| E_INVALIDARG | The pdwCapabilitiesMask parameter is an invalid or NULL pointer. |
| E_FAIL | An unspecified error occurred. |
Remarks
Currently, not many devices report their capabilities correctly.
Example Code
The following C++ code retrieves the device capabilities.
// Examine the device capabilities.
// Use some of these to enable or disable the application's
// user interface elements.
CComQIPtr<IWMDMDeviceControl> pDeviceControl(pIWMDMDevice);
if (pDeviceControl != NULL)
{
DWORD caps = 0;
hr = pDeviceControl->GetCapabilities(&caps);
if (caps & WMDM_DEVICECAP_CANPLAY)
{
// TODO: Display a message indicating that the media device can play MP3 audio.
}
if (caps & WMDM_DEVICECAP_CANSTREAMPLAY)
{
// TODO: Display a message that the device can play audio directly from the host computer.
}
if (caps & WMDM_DEVICECAP_CANRECORD)
{
// TODO: Display a message that the device can record audio.
}
if (caps & WMDM_DEVICECAP_CANSTREAMRECORD)
{
// TODO: Display a message that the media device can record
// streaming audio directly to the host computer.
}
if (caps & WMDM_DEVICECAP_CANPAUSE)
{
// TODO: Display a message that the device can pause during play or record operations.
}
if (caps & WMDM_DEVICECAP_CANRESUME)
{
// TODO: Display a message that the device can resume an operation that was paused.
}
if (caps & WMDM_DEVICECAP_CANSTOP)
{
// TODO: Display a message that the device can stop playing before the end of a file.
}
if (caps & WMDM_DEVICECAP_CANSEEK)
{
// TODO: Display a message that the device can seek to a position
// other than the beginning of the file.
}
if (caps & WMDM_DEVICECAP_HASSECURECLOCK)
{
// TODO: Display a message indicating that the device has a secure clock.
}
}
Requirements
Header: Defined in mswmdm.h.
Library: mssachlp.lib
See Also