[C++-sig] try-except for non-standard exception

[Roman Yakovenko]

On Tue, Apr 15, 2008 at 5:17 PM, Håkon Groven <hgroven at emgs.com> wrote:
> Hi!
>
>  I'm trying to expose my cpp-defined exception so that i can do something
>  like this in Python:
>
>  try:
>     value = someObject.someFunction()
>  except Pyelio.ElioError, e:
>     print e.what()
>
>  I have tried to do the following in the cpp wrapper:
>
>  namespace
>  {
>      struct emgs_elio_ElioError_Wrapper: ElioError
>      {
>          emgs_elio_ElioError_Wrapper(PyObject* py_self_, const
>  ElioError& p0):
>          ElioError(p0), py_self(py_self_)
>          {}
>
>          emgs_elio_ElioError_Wrapper(PyObject* py_self_):
>          ElioError(), py_self(py_self_)
>          {}
>
>          emgs_elio_ElioError_Wrapper(PyObject* py_self_, const
>  std::string& p0):
>          ElioError(p0), py_self(py_self_)
>          {}
>
>          const char* what() const throw()
>          {
>              return call_method< const char* >(py_self, "what");
>          }
>
>          const char* default_what() const
>          {
>              return ElioError::what();
>          }
>
>          PyObject* py_self;
>      };
>
>      void translate(ElioError const& e)
>      {
>          PyErr_SetString(PyErr_NewException(
>                  "Pyelio.ElioError",
>                  PyExc_StandardError, NULL),
>                  e.what());
>      };
>  }
>
>  BOOST_PYTHON_MODULE(Pyelio)
>  {
>     register_exception_translator<ElioError>(&translate();
>
>      class_< ElioError, emgs_elio_ElioError_Wrapper >("ElioError", init<
>  const ElioError& >())
>      .def(init< optional< const std::string& > >())
>      .def("what", (const char* (ElioError::*)() const
>  throw())&ElioError::what, (const char*
>  (emgs_elio_ElioError_Wrapper::*)()
>  const)&emgs_elio_ElioError_Wrapper::default_what)
>      .def("printStackTrace", &ElioError::printStackTrace)
>      ;
>
>  }
>
>  Because of my translate function my exception is a standard error on the
>  python side and not a Pyelio.ElioError. However, if i print type(e) in
>  python I get the string from my translate func: "Pyelio.ElioError".
>
>  I would be very thankful if anybody could help me out/post a minimal
>  example of how to wrap/expose a cpp-defined exception.

http://language-binding.net/pyplusplus/troubleshooting_guide/exceptions/exceptions.html

HTH


-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/