mixerGetControlDetails always return FFFF on Win8.1 and Win10 - windows

Question

I'm trying to read the current volume level.
I moved from the waveOut* functions to the mixer* functions.
If I run the application under Windows XP the value are aligned with the system volume level.
If I run under Win8.1 and Win10 I always receive 0xFFFF.
My code is:
TCHAR msg[100];
g_uNumDevs = mixerGetNumDevs();
wsprintf( msg, L"N. mixer: %d", g_uNumDevs);
pInfo->Log(msg);
if (g_uNumDevs)
{
UINT i = 0;
while(i < g_uNumDevs)
{
MMRESULT mmRes = mixerOpen(&hMixer, i, 0, 0, MIXER_OBJECTF_MIXER);
if (mmRes != MMSYSERR_NOERROR)
{
wsprintf( msg, L"Errore openMixer i:%d err:%d", i, mmRes);
pInfo->Log(msg);
}
// Master line
MIXERLINE ml = {0};
ml.cbStruct = sizeof(MIXERLINE);
ml.dwComponentType = MIXERLINE_COMPONENTTYPE_DST_SPEAKERS; // Volume master
mmRes = mixerGetLineInfo((HMIXEROBJ) hMixer, &ml, MIXER_GETLINEINFOF_COMPONENTTYPE);
pInfo->Log( ml.szName);
if (mmRes != MMSYSERR_NOERROR)
{
wsprintf( msg, L"Errore mixerGetLineInfo err:%d", mmRes);
pInfo->Log(msg);
mixerClose(hMixer);
return FALSE;
}
// get the volume control of the speaker line.
MIXERLINECONTROLS mlc = {0};
MIXERCONTROL mc = {0};
mlc.cbStruct = sizeof(MIXERLINECONTROLS);
mlc.dwLineID = ml.dwLineID;
mlc.dwControlType = MIXERCONTROL_CONTROLTYPE_VOLUME;
mlc.cControls = 1;
mlc.pamxctrl = &mc;
mlc.cbmxctrl = sizeof(MIXERCONTROL);
mmRes = mixerGetLineControls((HMIXEROBJ) hMixer, &mlc, MIXER_GETLINECONTROLSF_ONEBYTYPE);
if (mmRes != MMSYSERR_NOERROR)
{
wsprintf( msg, L"Errore mixerGetLineControls err:%d", mmRes);
pInfo->Log(msg);
EnableWindow( g_hwndSlider, FALSE);
EnableWindow( g_hwndVerifBtn, FALSE);
}
else {
// GetVolume level
MIXERCONTROLDETAILS_UNSIGNED mxcdVolume;
MIXERCONTROLDETAILS mxcd;
mxcd.cbStruct = sizeof(MIXERCONTROLDETAILS);
mxcd.dwControlID = mc.dwControlID;
mxcd.cChannels = 1;
mxcd.cMultipleItems = 0;
mxcd.cbDetails = sizeof(MIXERCONTROLDETAILS_UNSIGNED);
mxcd.paDetails = &mxcdVolume;
mmRes = mixerGetControlDetails(reinterpret_cast<HMIXEROBJ>(hMixer),
&mxcd, MIXER_OBJECTF_HMIXER | MIXER_GETCONTROLDETAILSF_VALUE);
if (mmRes != MMSYSERR_NOERROR)
{
EnableWindow( g_hwndSlider, FALSE);
EnableWindow( g_hwndVerifBtn, FALSE);
//return FALSE;
}
else {
DWORD dwVol = mxcdVolume.dwValue;
dwVol &= 0xFFFF;
DWORD perc = dwVol * 100 / 0xFFFF;
SendMessage( g_hwndSlider, TBM_SETPOS, 1, perc);
wsprintf( msg, L"Volume = %d %% [%d]", perc, dwVol);
pInfo->Log(msg);
}
}
mixerClose(hMixer);
++i;
} // while
}
else {
pInfo->Log(L"No audio device !!");
return FALSE;
}