Igor R writes:

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I read on google that you can only use shared_from_this on ONE class type

in a

...

class hierarchy. I did not understand the details of why.

You probably mean that you should inherit enable_shared_from_this only once. But then you can use shared_from_this wherever you wish.

I inherited from enable_shared_from_this in my base class. When I called shared_from_this() in my derived class it throws an exception. When I go up the call stack I see that in the boost implementation weak_ptr is NULL and count is NULL. I ensured the derived class was instatiated as a shared_ptr by using a fatory method. I don't know what else to do.

Igor R writes:

...

I inherited from enable_shared_from_this in my base class. When I called shared_from_this() in my derived class it throws an exception. When I go up the call stack I see that in the boost implementation weak_ptr

is

...

NULL and count is NULL.

I ensured the derived class was instatiated as a shared_ptr by using a fatory method.

If you create shared_ptr, as you described, and then call shared_from_this(), it should not throw exceptions. If it does, can you provide a trivial reproducing sample?

Well, I tried to get a trivial example and ended up having a working example. I suppose my problem is in the non-trivial part of my code :) Is this the correct way to do it? #include <iostream> #include #include //-------------------------- class A : public boost::enable_shared_from_this<A> { public: /// typedef boost::shared_ptr<A> SmartPtr; /// static A::SmartPtr Create() { A::SmartPtr instance; // Check arguments if any // Create an instance of this class instance.reset(new A()); return instance; } virtual ~A() { } protected: A() { } }; //-------------------------- class B : public A { public: /// typedef boost::shared_ptr<B> SmartPtr; /// static B::SmartPtr Create() { B::SmartPtr instance; // Check arguments if any // Create an instance of this class instance.reset(new B()); return instance; } /// virtual ~B() { } /// B::SmartPtr Foo() { A::SmartPtr temp = shared_from_this(); B::SmartPtr me = boost::shared_dynamic_cast(temp); return me; } /// void Bar() const { std::cout << "Success!" << std::endl; } protected: /// B() : A() { } }; //-------------------------- int main() { B::SmartPtr b1 = B::Create(); B::SmartPtr b2 = b1->Foo(); if( b1 != b2 ) { std::cout << "they aren't equal." << std::endl; return 1; } b2->Bar(); return 0; }