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4/8/2010

This function queries the current volume setting of a waveform output device.

Syntax 

MMRESULT waveOutGetVolume(
  HWAVEOUT 
hwo, 
  LPDWORD 
pdwVolume 
);

Parameters

hwo

Handle to an open waveform-audio output device. This parameter can also be a device identifier.

pdwVolume

Pointer to a variable to be filled with the current volume setting. The low-order word of this location contains the left-channel volume setting, and the high-order word contains the right-channel setting. A value of 0xFFFF represents full volume, and a value of 0x0000 is silence.

If a device does not support both left and right volume control, the low-order word of the specified location contains the mono volume level.

The full 16-bit setting(s) set with the waveOutSetVolumefunction is returned, regardless of whether the device supports the full 16 bits of volume-level control.

Return Value

One of the values described in the following table is returned.

Value Description

MMSYSERR_NOERROR

Success.

MMSYSERR_INVALHANDLE

Specified device handle is invalid.

MMSYSERR_NODRIVER

No device driver is present.

MMSYSERR_NOMEM

Unable to allocate or lock memory.

MMSYSERR_NOTSUPPORTED

Function is not supported.

MMSYSERR_BADDEVICEID 

Specified device identification number is out of range.

Remarks

If a device identifier is used, then the result of the waveOutGetVolumecall and the information returned in pdwVolumeapplies to all instances of the device. If a device handle is used, then the result and information returned applies only to the instance of the device referenced by the device handle.

Not all devices support volume changes. To determine whether the device supports volume control, use the WAVECAPS_VOLUME flag to test the dwSupportmember of the WAVEOUTCAPSstructure (filled by the waveOutGetDevCapsfunction).

To determine whether the device supports left- and right-channel volume control, use the WAVECAPS_LRVOLUME flag to test the dwSupportmember of the WAVEOUTCAPSstructure (filled by waveOutGetDevCaps).

Volume settings are interpreted logarithmically. This means the perceived increase in volume is the same when increasing the volume level from 0x5000 to 0x6000 as it is from 0x4000 to 0x5000.

Requirements

Header mmsystem.h
Library coredll.lib
Windows Embedded CE Windows CE 2.0 and later
Windows Mobile Windows Mobile Version 5.0 and later

See Also