ISimpleAudioVolume::SetMasterVolume method (audioclient.h)

The SetMasterVolume method sets the master volume level for the audio session.

Syntax

HRESULT SetMasterVolume(
  [in] float   fLevel,
  [in] LPCGUID EventContext
);

Parameters

[in] fLevel

The new master volume level. Valid volume levels are in the range 0.0 to 1.0.

[in] EventContext

Pointer to the event-context GUID. If a call to this method generates a volume-change event, the session manager sends notifications to all clients that have registered IAudioSessionEvents interfaces with the session manager. The session manager includes the EventContext pointer value with each notification. Upon receiving a notification, a client can determine whether it or another client is the source of the event by inspecting the EventContext value. This scheme depends on the client selecting a value for this parameter that is unique among all clients in the session. If the caller supplies a NULL pointer for this parameter, the client's notification method receives a NULL context pointer.

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.

Remarks

This method generates a volume-change event only if the method call changes the volume level of the session. For example, if the volume level is 0.4 when the call occurs, and the call sets the volume level to 0.4, no event is generated.

Requirements

See also

IAudioSessionEvents Interface

ISimpleAudioVolume Interface

ISimpleAudioVolume::GetMasterVolume