fpc 3.2.2 + win32api Call's - can't properly use RegisterClassEx

[paule32]

when I use this code fragment, I get segfault with the gdb on RegisterClassEx

Code: Pascal  [Select][+][-]

1. function GlobalWndProc(id: HWND; Msg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall; export;
2. var
3.   winCtrl: TWinControl;
4. begin
5.   if msg = WM_NCCREATE then
6.   begin
7.     winCtrl := TWinControl(GetWindowLongPtrA(id, GWLP_USERDATA));
8.     SetWindowLongPtrA(id, GWLP_USERDATA, NativeInt(winCtrl));
9.     winCtrl.FHandle := id;
10.   end else
11.   winCtrl := TWinControl(GetWindowLongPtrA(id, GWLP_USERDATA));
12.  
13.   if Assigned(winCtrl) then
14.   Result := winCtrl.HandleMessage (id, Msg, wParam, lParam) else
15.   Result := DefWindowProcA        (id, Msg, wParam, lParam) ;
16. end;
17.  
18. function TWinControl_Create(p: TWinControl): TWinControl; stdcall; export;
19. var
20.   _msg: TMsg;
21.   cls : TWndClassEx;
22.   wrd : WordBool;
23.   hin : HINSTANCE;
24. begin
25.   {$ifdef DLLDEBUG}
26.   writeln('TWinControl: Create');
27.   {$endif DLLDEBUG}
28.  
29.   if p = nil then
30.   begin
31.     ShowError(sError_TWinControl_ref);
32.     exit(nil);
33.   end;
34.  
35.   hin := GetModuleHandleA(nil);
36.  
37.   FillChar(cls, sizeof(cls), 0);
38.   cls.cbSize          := sizeof(cls);        { must be initialized   }
39.  
40.   if not GetClassInfoEx (hin, 'AppName', @cls) then
41.   begin
42.     with cls do
43.     begin
44.       style           := CS_BYTEALIGNCLIENT;
45.       lpfnWndProc     := @GlobalWndProc;              { window class handler  }
46.       cbClsExtra      := 0;
47.       cbWndExtra      := 0;
48.       hInstance       := hin;                         { qualify instance!     }
49.       hIcon           := LoadIconA(hin, 'APPICON');
50.       hCursor         := LoadCursorA(0, 'idc_arrow');
51.       hbrBackground   := GetSysColorBrush(COLOR_WINDOW);
52.       lpszMenuName    := 'APPMENU';                   { Menu name             }
53.       lpszClassName   := 'AppName';                   { Window Class name     }
54.       (*hIconSm         := LoadImage(
55.       hin,
56.       APPICON,
57.       IMAGE_ICON,
58.       16,
59.       16,
60.       LR_DEFAULTCOLOR*
61.       );*)
62.     end;
63.  
64.     // the line below is always 0 - why ? - not correct cls init
65.     if RegisterClassExA(@cls) = 0 then
66.     begin
67.       ShowError('regois error.');
68.       Halt(255);
69.     end;
70.   end;

I get no compiler error's or warnings