With something like this:

// Get the number of auxilary audio devs //
int numdevs = auxGetNumDevs();
int devid = 0;
AUXCAPS auxCaps;

// Find the CDAudio device //
for (int i = 0 ; i < numdevs ; i ++)
{
auxGetDevCaps(i, &auxCaps, sizeof(auxCaps));

devid = i;
i = numdevs;
}

// Change the volume & check against limits//
if (vol > 100) vol = 100;
if (vol < 0) vol = 0;
auxSetVolume(devid, vol*655);

-Geoff

Does any one knows how to control CD Audio's
Volume?MCI?I think it's not easy.

Wouldn't this alter the midi volume as well? I suggest if you are trying to alter just the one volume, get the device id for the cdrom when you open it for use:

char buffer[16], command[64];

strcpy(command, "open cdaudio wait");
mciSendString(command, buffer, 16, NULL);
buffer[15] = 0;
device_id = atoi(buffer);

Then proceed with the rest as Geoff suggested. This works for all devices
that need an id.

------------------
Jim Adams
Co-Designer 'The Light Befallen'
tcm@pobox.com
http://www.lightbefallen.com