I have found a discussion called "Getting Python Object from C++ object" : http://osdir.com/ml/python.c++/2003-08/msg00191.html It use shared_ptr and boost "enable_shared_from_this" template. Thanks to this, we could "just write object(p) to get the Python object back." like described in the FAQ. I have modified the code so as to implement a function which copy the dict of an object "A" to the dict of another object "A" ( implementing this as operator= would be better, but it's just to test ). I've added the objects A to a container of type C so as to create a shared_ptr and make sure that self() will return a valid shared_ptr. However, it didn't seems to work, it crash when i try to do a "object (self())" so as to get the python object : ---------------------- #include <assert.h> #include <iostream> #include <string> #include <boost/shared_ptr.hpp> #include <boost/enable_shared_from_this.hpp> #include <boost/python.hpp> using namespace boost; using namespace boost::python; struct RuntimeError { RuntimeError( std::string msg ) : message( msg ) { } const char *what() const throw() { return message.c_str(); } std::string message; }; void runtime_error( RuntimeError const &x ) { PyErr_SetString( PyExc_RuntimeError, x.what() ); } class A : public enable_shared_from_this<A> { public: typedef shared_ptr<A> A_ptr; /* Here 'a' tries to get the shared_ptr representing the * python object from boost::python. * Certainly this only works after a shared pointer has * actually been created, e.g. by adding 'a' to a container * of type C. After that, shared_from_this() actually returns * a valid shared_ptr, which can be used for getting the * respective python::object. */ virtual A_ptr self() { if ( _internal_weak_this.expired() ) throw RuntimeError( "Shared pointer not available." ); shared_ptr<A> self = shared_from_this(); assert( self != 0 ); return self; } //Very simple function to copy the dict of the python objects void Copy( A & o ) { object(self()).attr("__dict__") = object(o.self()).attr ("__dict__"); } virtual ~A() {}; }; class C { private: typedef A::A_ptr A_ptr; public: void set( A_ptr a ) { this->a = a; } // store instance A_ptr get() { return this->a; } private: A_ptr a; }; BOOST_PYTHON_MODULE( self_test ) { register_exception_translator<RuntimeError>( &::runtime_error ); class_<A>( "A" ).def( "self", &A::self ); class_<C>( "C" ).def( "set", &C::set ).def( "get", &C::get ); } int main() { PyImport_AppendInittab( "self_test", &initself_test ); Py_Initialize(); A a_cpp; A a2_cpp; object main_module(( handle<>( borrowed( PyImport_AddModule ( "__main__" ) ) ) ) ); object main_namespace = main_module.attr( "__dict__" ); object self_test(( handle<>( PyImport_ImportModule ( "self_test" ) ) ) ); main_namespace["self_test"] = self_test; main_namespace["a"] = &a_cpp; main_namespace["a2"] = &a2_cpp; try { handle<> ignored(( PyRun_String( "c = self_test.C();c.set (a);a.self();print a;a.member=42;", Py_file_input, main_namespace.ptr(), main_namespace.ptr() ) ) ); handle<> ignored(( PyRun_String( "c2 = self_test.C();c2.set (a2);a2.self();print a2;a2.othermember=23;", Py_file_input, main_namespace.ptr(), main_namespace.ptr() ) ) ); } catch ( error_already_set ) { PyErr_Print(); } a2_cpp.Copy(a_cpp); //Crash } ---------------------- Theorically, the call to C::set would prevent the crash... On 28 août, 00:19, OvermindDL1 <overmind...@gmail.com> wrote:
On Thu, Aug 27, 2009 at 10:46 AM, 4ian<dark4...@gmail.com> wrote:
I'm afraid I'm unable to find this class or anything that can help me to copy the Python __dict__ associated with my C++ object...
On 25 août, 21:55, OvermindDL1 <overmind...@gmail.com> wrote:
On Tue, Aug 25, 2009 at 3:52 AM, 4ian<dark4...@gmail.com> wrote:
Thanks for you response ! When you say "that one wrapper helper", are you speaking about the object class of Boost.python, or about a home made class ?
Neither. I do not recall the name of it, but you can subclass your class from it, then anytime your class has a python object containing it then you can use some getself comand or something like that, it is in the docs somewhere (but I am not in a good position to look at the docs right now, maybe tonight if you have not found it yet).
Found it, it is in the FAQ, apparently the wrapper class I used was one I made, but it talks about how to make it there, and an alternate/better method if you are using shared_ptr:http://beta.boost.org/doc/libs/1_40_0/libs/python/doc/v2/faq.html#xref _______________________________________________ Boost-users mailing list Boost-us...@lists.boost.orghttp://lists.boost.org/mailman/listinfo.cgi/boost-users