program hello;
 
uses
    Windows, Messages;
 
function WndProc(hWindow:HWnd; message:Cardinal; wParam:Word; lParam:Longint):LongWord; stdcall;
var
    hdc:        THandle;
    ps:         TPaintStruct;
const
    strMessage = 'Hello, Win32 GUI(Delphi) World!';
begin
    case message of
        WM_PAINT:
            begin
                hdc := BeginPaint(hWindow, ps );
                TextOut( hdc, 0, 0, strMessage, Length(strMessage) );
                EndPaint( hWindow, ps );
            end;
 
        WM_DESTROY:
            PostQuitMessage(0);
    else
        Result := DefWindowProc(hWindow, message, wParam, lParam);
        exit;
    end;
    Result := 0;
end;
 
function WinMain(hInstance, hPrevInstance:THandle; lpCmdLine:PAnsiChar; nCmdShow:Integer):Integer; stdcall;
var
    wcex:       TWndClassEx;
    hWindow:    HWnd;
    msg:        TMsg;
const
    ClassName = 'helloWindow';
    WindowName = 'Hello, World!';
 
begin
    wcex.cbSize         := SizeOf(TWndclassEx);
    wcex.style          := CS_HREDRAW or CS_VREDRAW;
    wcex.lpfnWndProc    := @WndProc;
    wcex.cbClsExtra     := 0;
    wcex.cbWndExtra     := 0;
    wcex.hInstance      := hInstance;
    wcex.hIcon          := LoadIcon(0, IDI_APPLICATION);
    wcex.hCursor        := LoadCursor(0, IDC_ARROW);
    wcex.hbrBackground  := COLOR_WINDOW +1;
    wcex.lpszMenuName   := nil;
    wcex.lpszClassName  := ClassName;
 
    RegisterClassEx(wcex);
    hWindow := CreateWindowEX(
        0,
        ClassName,
        WindowName,
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 640, 480,
        0, 0, hInstance, nil
    );
 
    ShowWindow(hWindow, SW_SHOWDEFAULT);
    UpdateWindow(hWindow);
 
    while GetMessage(msg, 0, 0, 0) do begin
        TranslateMessage(msg);
        DispatchMessage(msg);
    end;
 
    Result := msg.wParam;
end;
 
begin
    WinMain( hInstance, 0, nil, cmdShow );
end.

C:¥> dcc32 hello.pas

+------------------------------------------+
|Hello, World!                    [_][~][X]|
+------------------------------------------+
|Hello, Win32 GUI(Delphi) World!           |
|                                          |
|                                          |
|                                          |
|                                          |
|                                          |
|                                          |
|                                          |
|                                          |
|                                          |
+------------------------------------------+