[Boost-users] enable_shared_from_this

From: sashan (sashang_at_[hidden])
Date: 2003-10-21 19:39:25

I'm trying to use enable_shared_from_this with my classes that have an 
inheritance structure and a virtual function.
I'd like to get a shared pointer to the descendant class B. I get a 
compile error when I try to dynamic cast the shared ptr of type A to a 
shared_ptr of type B. See the attached sample.

-- 
sashan
http://www.cs.auckland.ac.nz/~sgov008/

#include <iostream>
#include <boost/enable_shared_from_this.hpp>

using namespace std;
using namespace boost;

class A :
        public enable_shared_from_this<A>
{
public:
        A(){ cout << "A" << endl; }
        virtual void f() =0;
};

class B : 
        public A

{
public:
        B() { cout << "B" << endl;}
        virtual void f() 
        {		
                shared_ptr<A> pA(enable_shared_from_this<A>::shared_from_this());
                shared_ptr<B> pB1(dynamic_pointer_cast < shared_ptr<B> >(pA));
        }
};
void main()
{
        B b;
        b.f();
}