WORD auxSetVolume(wDeviceID, dwVolume)
This function sets the volume in an auxiliary output device.
WORD wDeviceID
Identifies the auxiliary output device to be queried. Device IDs are determined implicitly from the number of devices present in the system. Device ID values range from zero to one less than the number of devices present. Use auxGetNumDevs to determine the number of auxiliary devices in the system.
DWORD dwVolume
Specifies the new volume setting. The low-order word specifies the left channel volume setting, and the high-order word specifies 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 dwVolume specifies the volume level, and the high-order word is ignored.
Returns zero if the function was successful. Otherwise, it returns an error number. Possible error returns are:
MMSYSERR_BADDEVICEID
Specified device ID is out of range.
MMSYSERR_NODRIVER
The driver failed to install.
Not all devices support volume control. To determine whether the device supports volume control, use the AUXCAPS_VOLUME flag to test the dwSupport field of the AUXCAPS structure (filled by auxGetDevCaps).
To determine whether the device supports volume control on both the left and right channels, use the AUXCAPS_LRVOLUME flag to test the dwSupport field of the AUXCAPS structure (filled by auxGetDevCaps).
Most devices do not support the full 16 bits of volume level control and will use only the high-order bits of the requested volume setting. For example, for a device that supports 4 bits of volume control, requested volume level values of 0x4000, 0x4fff, and 0x43be will all produce the same physical volume setting, 0x4000. The auxGetVolume function will return the full 16-bit setting set with auxSetVolume.
Volume settings are interpreted logarithmically. This means the perceived volume increase is the same when increasing the volume level from 0x5000 to 0x6000 as it is from 0x4000 to 0x5000.
auxGetVolume