IAudioStreamVolume::GetAllVolumes method (audioclient.h)
The GetAllVolumes method retrieves the volume levels for all the channels in the audio stream.
HRESULT GetAllVolumes( UINT32 dwCount, float *pfVolumes );
The number of elements in the pfVolumes array. The dwCount parameter must equal the number of channels in the stream format. To get the number of channels, call the IAudioStreamVolume::GetChannelCount method.
Pointer to an array of volume levels for the channels in the audio stream. This parameter points to a caller-allocated float array into which the method writes the volume levels for the individual channels. Volume levels are in the range 0.0 to 1.0.
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.
||Parameter dwCount does not equal the number of channels in the stream.|
||Parameter pfVolumes is NULL.|
||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.|
||The Windows audio service is not running.|
|Minimum supported client||Windows Vista [desktop apps only]|
|Minimum supported server||Windows Server 2008 [desktop apps only]|