how to overload the windows procedure?

[classicalhacker]

i want to overload the windows procedure to control ,how does application deal with the message sent. now,the development tool i used is Borland C++ Builder 6.0.You also give me the samples in another development tool.
thanks

classicalhacker

[Mithoric]

To overload the procedure just do this --

WNDPROC OldWndProc = SetWindowLong( hwnd, GWL_PROC, (LONG)NewWndProc );

Obviously hwnd is the window handle and OldWndProc is the old window procedure, instead of using DefWindowProc in your NewWndProc use CallWindowProc, it is the same but the first param is the OldWndProc and then it's just hwnd,msg,wParam,lParam as normal.

[Davros]

Have a look at the WindowProc property and WndProc method in TForm.