delphi mutex

//single mode program Project1; uses   Windows,   Forms,   Unit1 in 'Unit1.pas' {Form1}; {$R *.RES} const   MutexName = 'onlyone_MUTEX';   ClassName = 'TForm1';   WindowName = 'Form1'; var   Mutex: THandle;   Handle: THandle; begin   Mutex := OpenMutex(MUTEX_ALL_ACCESS, False, MutexName);   if Mutex <> 0 then   begin     Handle := FindWindow(ClassName, WindowName);     SetForegroundWindow(Handle);     Exit;   end;   CreateMutex(nil, False, MutexName);   Application.Initialize;   Application.CreateForm(TForm1, Form1);   Application.Run; end.