Spg ang.. Hotkeys

Virker perfekt, men jeg får nogle warnings?:
[Warning] Unit1.pas(31): Comparing signed and unsigned types - widened both operands

Spg. 2 hvordan kan jeg opfange hvilken tast der bliver trykket på ? har fundet ud at tast A har værdien 65 så jeg kan skrive Registerhotkey(Handle, ALT_A, MOD_ALT, 65); hvordan finder jeg værdien på de andre taster på mit keyboard? som f.eks de extra taster(play, pause, vloume osv.) som logitech keyboards har.

  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    ALT_A, ALT_B : THandle;
    procedure WMHOTKEY(var message: TMessage); message WM_HOTKEY;
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.WMHOTKEY(var message: TMessage);
begin
    if message.wParam = ALT_A then ShowMessage('ALT + A')
    else if message.wParam = ALT_B then ShowMessage('ALT + B')
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  ALT_A := GlobalAddAtom('test_ALT_A');
  ALT_B := GlobalAddAtom('test_ALT_B');
  Registerhotkey(Handle, ALT_A, MOD_ALT, Ord('A'));
  Registerhotkey(Handle, ALT_B, MOD_ALT, Ord('B'));
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  UnRegisterHotkey(Handle, ALT_A);
  UnRegisterHotkey(Handle, ALT_B);
  GlobalDeleteAtom(ALT_A);
  GlobalDeleteAtom(ALT_B);
end;

end.
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    ALT_A, ALT_B : THandle;
    procedure WMHOTKEY(var message: TMessage); message WM_HOTKEY;
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.WMHOTKEY(var message: TMessage);
begin
    if message.wParam = ALT_A then ShowMessage('ALT + A')
    else if message.wParam = ALT_B then ShowMessage('ALT + B')
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  ALT_A := GlobalAddAtom('test_ALT_A');
  ALT_B := GlobalAddAtom('test_ALT_B');
  Registerhotkey(Handle, ALT_A, MOD_ALT, Ord('A'));
  Registerhotkey(Handle, ALT_B, MOD_ALT, Ord('B'));
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  UnRegisterHotkey(Handle, ALT_A);
  UnRegisterHotkey(Handle, ALT_B);
  GlobalDeleteAtom(ALT_A);
  GlobalDeleteAtom(ALT_B);
end;

end.
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    ALT_A, ALT_B : THandle;
    procedure WMHOTKEY(var message: TMessage); message WM_HOTKEY;
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.WMHOTKEY(var message: TMessage);
begin
    if message.wParam = ALT_A then ShowMessage('ALT + A')
    else if message.wParam = ALT_B then ShowMessage('ALT + B')
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  ALT_A := GlobalAddAtom('test_ALT_A');
  ALT_B := GlobalAddAtom('test_ALT_B');
  Registerhotkey(Handle, ALT_A, MOD_ALT, Ord('A'));
  Registerhotkey(Handle, ALT_B, MOD_ALT, Ord('B'));
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  UnRegisterHotkey(Handle, ALT_A);
  UnRegisterHotkey(Handle, ALT_B);
  GlobalDeleteAtom(ALT_A);
  GlobalDeleteAtom(ALT_B);
end;

end.
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    ALT_A, ALT_B : THandle;
    procedure WMHOTKEY(var message: TMessage); message WM_HOTKEY;
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.WMHOTKEY(var message: TMessage);
begin
    if message.wParam = ALT_A then ShowMessage('ALT + A')
    else if message.wParam = ALT_B then ShowMessage('ALT + B')
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  ALT_A := GlobalAddAtom('test_ALT_A');
  ALT_B := GlobalAddAtom('test_ALT_B');
  Registerhotkey(Handle, ALT_A, MOD_ALT, Ord('A'));
  Registerhotkey(Handle, ALT_B, MOD_ALT, Ord('B'));
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  UnRegisterHotkey(Handle, ALT_A);
  UnRegisterHotkey(Handle, ALT_B);
  GlobalDeleteAtom(ALT_A);
  GlobalDeleteAtom(ALT_B);
end;

end.