On 05/11/2012 18:51, Martin Hellmich wrote:
Hi,
I have a custom exception in C++ that I would like to use in Python.
Let's call it MyException with custom constructor and members (an
implementation is below).
I would like to expose it to python so that I can raise it:
> raise MyException(-1, 'tragic error')
The perfect way that I can imagine is to tell boost::python to base the class
on PyExc_Exception, but that doesn't seem to work. Furthermore I have found
various solutions how to translate exceptions thrown in C++ into proper Python
exceptions, but in my case these solutions sit at the wrong place.
I've based my code on.
http://stackoverflow.com/questions/9620268/boost-python-custom-exception-class
I would like to avoid to create a corresponding python class to the C++
exception, because there would be added effort to keep the two descriptions
consistent.
True.
class MyException: public std::exception {
MyException();
MyException(int code, const std::string &string);
int code();
const char* what();
int errorCode;
std::string errorMessage;
};
The only unusual stuff is that you need both code and message. 2 ideas come to
mind.
1) you can base the python exception not on PyExc_Exception but on a custom
class which can handle both error code and message, so the exception
translator can do both a PyErr_SetString and a "PyErr_SetCode". This way you
can use the exception in both C and Python in the same style, no need to keep
anything in sync.
2) you can base the Python exception on the standard PyExc_Exception but use
PyErr_SetObject in the exception translator. A quick search finds this
http://stackoverflow.com/questions/2261858/boostpython-export-custom-exception
(does not inherit from Exception, though)
--
Giuseppe Corbelli
WASP Software Engineer, Copan Italia S.p.A
Phone: +390303666318 Fax: +390302659932
E-mail: giuseppe.corbe...@copanitalia.com
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