CreateWindowEx stack overrun?

[sansimarkus]

mal den code abgespeckt (und createwindowex durch createwindow ersetzt)

Delphi-Quellcode:

unit CoreWndObj;

interface

uses
  System.SysUtils,
  System.Classes,
  system.Types,

  Winapi.Windows,
  Winapi.Messages;


type
 TCoreWnd = class(TObject)
   private
     myhWnd:      HWND;
   public
      constructor    create();
 end;




implementation

function WndProc(i_hWnd:HWND;i_Message:LongWord;i_wParam:WPARAM;i_lParam:LPARAM):LResult;
begin
  result := DefWindowProc(i_hWnd, i_Message, i_wParam, i_lParam);
end;


constructor TCoreWnd.create();
var
 wcex:       TWndClassEx;
 dwStyle:    dword;
 x,y: string;
begin

 inherited create;

 x := 'blablub';
 y := 'blblbl';

 ZeroMemory(@wcex,sizeof(wcex));
 with wcex do
  begin
   cbSize        :=  SizeOf(wcex);
   style         :=  CS_HREDRAW or CS_VREDRAW or CS_OWNDC;
   lpfnWndProc   :=  @wndproc;
   hInstance     :=  SysInit.HInstance;
   hCursor       :=  LoadCursor(0,IDC_ARROW);
   lpszClassName :=  PChar(x);
   hbrBackground :=  1;
  end;

 if RegisterClassEx(wcex) = 0 then
  writeln('error');

 dwStyle   := WS_OVERLAPPEDWINDOW or WS_CLIPSIBLINGS or WS_CLIPCHILDREN;


 myhWnd := CreateWindow( PChar(x),
                         PChar(y),
                         dwStyle,
                         120,
                         120,
                         1280,
                         768,
                         0,0,SysInit.HInstance,nil);
 if myhWnd = 0 then
  Writeln('error');

 ShowWindow(myhWnd, SW_SHOW);
 SetForegroundWindow(myhWnd);

end;

end.

gleicher Fehler, und trotzdem funktionierts einwandfrei als 64bit version.