[Boost-users] enable_shared_from_this

22 Oct 2003


      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();
}