[Dev-C++] Windows Volume (get/set)

Hi,
I whant to get and set the main volume.
Well, I mean the value from the volume control at the tray bar from windows.
I'm sure it could be done with the Windows API, but I don't know how...
I tried it like this:

double GetWaveVolumePercent(bool blLeft){
  unsigned long ulCurrentVolume = 0;
  if(waveOutGetVolume(0, (LPDWORD) &ulCurrentVolume) == MMSYSERR_NOERROR){
    if(blLeft) return double(double(LOWORD(ulCurrentVolume))*100.0/65535.0);
    else return double(double(HIWORD(ulCurrentVolume))*100.0/65535.0);
  }
  else return 0.0;
}

bool SetWaveVolumePercent(double dlValue, bool blLeft){
  unsigned long ulCurrentVolume = 0;
  if(dlValue < 0.0) dlValue = 0.0;
  else if(dlValue > 100.0) dlValue = 100.0;
  if(waveOutGetVolume(0, (LPDWORD) &ulCurrentVolume) == MMSYSERR_NOERROR){
    WORD ilNewVolume = int(double(65535.0)/100.0*dlValue);
    if(blLeft) ulCurrentVolume = ulCurrentVolume & 0xFFFF0000 | ilNewVolume;
    else ulCurrentVolume = ulCurrentVolume & 0x0000FFFF | ilNewVolume*0x10000;
    return waveOutSetVolume(0, ulCurrentVolume) == MMSYSERR_NOERROR;
  }
  else return false;
}

But this is not what I whant and doesn't work at all...
I whant the main volume !!!

Any suggestions ???

thx, Acki