IAudioSessionControl::GetGroupingParam
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IAudioSessionControl::GetGroupingParam
The GetGroupingParam method retrieves the grouping parameter of the audio session.
HRESULT GetGroupingParam( GUID *pRetVal );
Parameters
pRetVal
[out] Output pointer for the grouping-parameter GUID. This parameter must be a valid, non-NULL pointer to a caller-allocated GUID variable. The method writes the grouping parameter into this variable.
Return Value
If the method succeeds, it returns S_OK. If it fails, possible return codes include, but are not limited to, the values shown in the following table.
| Return code | Description |
| E_POINTER | Parameter pRetVal is NULL. |
| AUDCLNT_E_DEVICE_INVALIDATED | The audio endpoint device has been unplugged, or the audio hardware or associated hardware resources have been reconfigured, disabled, removed, or otherwise made unavailable for use. |
| AUDCLNT_E_SERVICE_NOT_RUNNING | The Windows audio service is not running. |
Remarks
All of the audio sessions that have the same grouping parameter value are under the control of the same volume-level slider in the system volume-control program, Sndvol. For more information, see Grouping Parameters.
A client can call the IAudioSessionControl::SetGroupingParam method to change the grouping parameter of a session.
If a client has never called SetGroupingParam to assign a grouping parameter to an audio session, the session's grouping parameter value is GUID_NULL by default and a call to GetGroupingParam retrieves this value. A grouping parameter value of GUID_NULL indicates that the session does not belong to any grouping. In that case, the session has its own volume-level slider in the Sndvol program.
Requirements
Client: Windows Vista
Header: Include Audiopolicy.h.
See Also
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