unit uWMInterceptor;

{$mode ObjFPC}{$H+}
interface

uses
  SysUtils,  Forms,  Controls,  Windows, LazLogger;
var
  OldWndProc: WNDPROC;

procedure InitWMInterception(AFormHandle: THandle);

implementation

function NewWndCallback(Ahwnd: HWND; uMsg: UINT; wParam: WParam;
  lParam: LParam): LRESULT; stdcall;
begin
   { Traitement des messages intercéptés }
  case uMsg of
    WM_DEVICECHANGE: debugLn('Message : %x, %x, %x', [uMsg, wParam, lParam]);
  end;
  
  { Appel de l'ancienne WNDProc }
  Result := Windows.CallWindowProc(OldWndProc, Ahwnd, uMsg, WParam, LParam);
end;

procedure InitWMInterception(AFormHandle: THandle);
begin
  if AFormHandle <> 0 then
  
     { Defini NewWndCallback comme nouvel intercepteur et stock l'ancien dans OldWinProc }
    OldWndProc := Windows.WNDPROC(SetWindowLongPtr(AFormHandle, GWL_WNDPROC, PtrUInt(@NewWndCallback)));
end;

end.