The Babel C++ binding has one command line option particular to it. Using the option -cxx-ior-exception (or it's short form '-x') will generate C++ Babel stubs that check for a null IOR whenever a method is called on them. If a method is called on a Stub holding a null IOR, it will throw a NullIORException. If this option is not passed to Babel, the program will simply crash, as C++ would do normally with a null pointer.