[C++-sig] why does the "shared_ptr<X> const&" silently become 0xCCCCCCCC

[ZaeX]

No, I compiled boost.python with just ' --with-python '.

and I just made a last try to change the 'shared_ptr<A> const& ' to
'shared_ptr<A>&',
and things suddenly become right.  ^_^
well I don't quite understand what's going on inside though. maybe
'shared_ptr<A> const&' made temp copy (?)
----------------------------------------------------------------------------
struct A
{
       A()
       {
               cerr << "Creating A" << endl;
       }
};

class B
{
private:
    //   shared_ptr<A> const& m_ptr; //remove const
         shared_ptr<A> & m_ptr
public:
       //B(shared_ptr<A> const& ptr):m_ptr(ptr)
       B(shared_ptr<A> & ptr) : m_ptr(ptr)
       {
               cerr << "Creating B" << endl;
               cerr << m_ptr.get() << endl;
       }

       void ShowPtr() const
       {
                cout << m_ptr.get() << endl;
       }
};

BOOST_PYTHON_MODULE(TryIt)
{

    //   class_<B, auto_ptr<B> >("B",  init<shared_ptr<A> const&>())
         class_<B, auto_ptr<B> >("B", init<shared_ptr<A> &() )
               .def("ShowPtr", &B::ShowPtr);

       class_<A, shared_ptr&lt;A>, noncopyable >("A");
}
----------------------------------------------------
from TryIt import *
a = A() # Creating A
b = B(a) # Creating B, 0xABCDE
b.ShowPtr() # 0xABCDE


On Fri, Mar 13, 2009 at 5:57 AM, David Abrahams <dave at boostpro.com> wrote:

>
> on Thu Mar 12 2009, ZaeX <zaexage-AT-gmail.com> wrote:
>
> > I just built the boost.python 1.36 with Python2.6.1 and tried again, and
> it
> > still turned out to be 0xcccccccc in debug build.
>
> Have you read
>
> http://www.boost.org/doc/libs/1_38_0/libs/python/doc/building.html#python-debugging-builds
> ?
>
> --
> Dave Abrahams
> BoostPro Computing
> http://www.boostpro.com
> _______________________________________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/mailman/listinfo/cplusplus-sig
>



-- 
Time is mana, we must hurry
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/cplusplus-sig/attachments/20090313/e5ce8cc5/attachment.htm>