waveOutGetVolume

The waveOutGetVolume function retrieves the current volume level of the specified waveform-audio output device.

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 waveOutSetVolume function is returned, regardless of whether the device supports the full 16 bits of volume-level control.

Return Values

Returns MMSYSERR_NOERROR if successful or an error otherwise. Possible error values include the following.

Value Description
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 isn't supported.

Remarks

If a device identifier is used, then the result of the waveOutGetVolume call and the information returned in pdwVolume applies 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 dwSupport member of the WAVEOUTCAPS structure (filled by the waveOutGetDevCaps function).

To determine whether the device supports left- and right-channel volume control, use the WAVECAPS_LRVOLUME flag to test the dwSupport member of the WAVEOUTCAPS structure (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

  Windows NT/2000/XP: Included in Windows NT 3.1 and later.
  Windows 95/98/Me: Included in Windows 95 and later.
  Header: Declared in Mmsystem.h; include Windows.h.
  Library: Use Winmm.lib.

See Also

Waveform Audio, Waveform Functions, waveOutSetVolume, WAVEOUTCAPS, waveOutGetDevCaps

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