I'm having some trouble with using shared_ptr, auto_ptr and enable_shared_from_this with my inheritance layout. The following is how my inheritance is laid out. // Inheritance Layout // // boost::enable_shared_from_this<T> // ^ // | // Base --------> IBase // ^ // | // Derived -----> IDerived In my test code (that I've included with this email) the following two ways to instantiate a shared pointer is equivalent. boost::shared_ptr<IDerived> r (new Derived()); std::auto_ptr<IDerived> k (new Derived); boost::shared_ptr<IDerived> l (k.release()); When creating the shared_ptr, both declaration take me to line 185 of shared_ptr.hpp. Instantiating the shared_ptr directly then takes me to line 105 of shared_ptr.hpp. Though when instantiating by releasing the auto_ptr into the shared_ptr I'm taken to line 129. It seems to me that I should be going to the same line of code. This wouldn't be such a problem except when trying to call shared_from_this() an exception is thrown if my shared_ptr was created from an auto_ptr. Is this behavior correct? Ryan #include <iostream> #include <memory> #include #include // Inheritance Layout // // boost::enable_shared_from_this<T> // ^ // | // Base --------> IBase // ^ // | // Derived -----> IDerived class IBase { public: virtual void hello(void) = 0; }; class Base : public IBase, public boost::enable_shared_from_this<Base> { public: Base(void){} ~Base(void){} void hello(void) { std::cout << "Hello" << std::endl; } }; class IDerived { public: virtual void world(void) = 0; static std::auto_ptr<IDerived> createAuto(void); static boost::shared_ptr<IDerived> createShared(void); virtual boost::shared_ptr<Base> root(void) = 0; virtual boost::shared_ptr<IBase> root2(void) = 0; }; class Derived : public IDerived, public Base { public: Derived(void){} ~Derived(void){} void world(void) { std::cout << "World" << std::endl; } virtual boost::shared_ptr<Base> root(void) { return shared_from_this(); } virtual boost::shared_ptr<IBase> root2(void) { return shared_from_this(); } }; std::auto_ptr<IDerived> IDerived::createAuto(void) { return std::auto_ptr<IDerived>(new Derived()); } boost::shared_ptr<IDerived> IDerived::createShared(void) { return boost::shared_ptr<IDerived>(new Derived()); } int main(int argc, char* argv[]) { boost::shared_ptr<IDerived> c = IDerived::createShared(); boost::shared_ptr<IBase> d = c->root2(); std::cout << c.use_count() << std::endl; boost::shared_ptr<IDerived> r (new Derived()); std::auto_ptr<IDerived> k (new Derived); boost::shared_ptr<IDerived> l (k.release()); boost::shared_ptr<IBase> m = l->root2(); std::cout << m.use_count() << std::endl; return 0; }