All C++ exceptions must be caught at the boundary with Python code. This boundary is the point where C++ meets Python. Boost.Python provides a default exception handler that translates selected standard exceptions, then gives up:
raise RuntimeError, 'unidentifiable C++ Exception'
Users may provide custom translation. Here's an example:
struct PodBayDoorException; void translator(PodBayDoorException const& x) { PyErr_SetString(PyExc_UserWarning, "I'm sorry Dave..."); } BOOST_PYTHON_MODULE(kubrick) { register_exception_translator< PodBayDoorException>(translator); ...