http://stackoverflow.com/questions/17652922/automatically-fr

type myClass = class(TMyInterfacedObject)
         public
            destructor Destroy; override;
     end;

destructor myClass.Destroy;
begin
   do cleanup
end;

procedure MyProcedure;
var IGuard: iInterface;
begin
   ...
   IGuard := myClass.Create(acquire resources);
....
end;  // IGuard is automatically decremented here and myClass destructor is called