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 of an
open waveform-audio output device. This parameter can also be a device
identifier.
pdwVolume
Address of 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:
|
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.
See Also