WODM_GETVOLUME

This message is used in an MMDRV_MESSAGE_PARAMS structure passed to the WAV_IOControl function to request a waveform output driver to return the current volume level setting for the specified device.

Parameters

uDeviceId

Device identifier—0, 1, 2, and so on—for the target device.

uMsg

Specifies this structure.

dwUser

Specifies a device instance identifier.

dwParam1

Pointer to a DWORD location to receive the volume setting.

dwParam2

Not used.

Return Values

MMSYSERR_NOERROR indicates success. Otherwise, the driver returns one of the MMSYSERR or WAVERR error values declared in the Mmsystem.h header file.

Remarks

The ACM sends this message by calling the audio driver’s WAV_IOControl entry point through the DeviceIoControl function. Support for this message by drivers is optional. However, if the driver supports WODM_SETVOLUME, it must support this message. The following table shows which bytes in dwParam1 indicate the volume settings for both stereo and monaural audio channels.

A value of 0 is silence, and a value of 0xFFFF is full volume.