[Boost-users] Problem with weak_ptr exception

Subject: [Boost-users] Problem with weak_ptr exception
From: Jacob Carlborg (doob_at_[hidden])
Date: 2009-10-28 07:43:08

I'm having some problems with bad_weak_ptr exceptions. I have reduced my 
code into this test case:

#include <boost/shared_ptr.hpp>
#include <boost/weak_ptr.hpp>

using boost::shared_ptr;
using boost::weak_ptr;

class A
{
                weak_ptr<A> weakThis;

        public:
                virtual ~A(){}

                shared_ptr<A> a;

        shared_ptr<A> getThis ()
        {
                shared_ptr<A> x(weakThis);
                return x;
        }

        void init ()
        {
                a = getThis();
        }

        static shared_ptr<A> create ()
        {
                shared_ptr<A> x(new A);

                x->weakThis = x;
                x->init();

                return x;
        }
};

class B : public A
{
                weak_ptr<B> weakThis;
        public:
                virtual ~B(){}

        shared_ptr<B> getThis ()
        {
                shared_ptr<B> b(weakThis);
                return b;
        }

        static shared_ptr<B> create ()
        {
                shared_ptr<B> x(new B);
                x->weakThis = x;
                x->init();

                return x;
        }
};

int main (char** argv, int argc)
{
        shared_ptr<B> b = B::create();

        return 0;
}

If I create an instance of A instead of B or doesn't call x->init() in 
the B's create function I don't get an exception. The problem is 
creating a shared_ptr from the weak_ptr in getThis.