Controling sound volume from code

Here's an example of controling the sound volume from Delphi:

uses MMSystem;

type
  TVolumeRec = record
    case Integer of
      0: (LongVolume: Longint) ;
      1: (LeftVolume, RightVolume : Word) ;
    end;

const DeviceIndex=5
      {0:Wave
       1:MIDI
       2:CDAudio
       3:Line-In
       4:Microphone
       5:Master
       6:PC-loudspeaker}
    
procedure SetVolume(aVolume:Byte) ;
var Vol: TVolumeRec;
begin
	Vol.LeftVolume := aVolume shl 8;
	Vol.RightVolume:= Vol.LeftVolume;
	auxSetVolume(UINT(DeviceIndex), Vol.LongVolume) ;
end;

function GetVolume:Cardinal;
var Vol: TVolumeRec;
begin
	AuxGetVolume(UINT(DeviceIndex),@Vol.LongVolume) ;
	Result:=(Vol.LeftVolume + Vol.RightVolume) shr 9;
end;