I ran onto a problem when using intrusive_ptr, overloading and MS visual studio 8 All my classes derive a reference counted class RefCnt. For example: class GLTexture : public RefCnt {...}; class GLRenderBuffer : public RefCnt {...}; I define smart pointers using the intrusive_ptr class: typedef boost::intrusive_ptr<GLTexture> GLTexturePtr; typedef boost::intrusive_ptr<GLRenderBuffer> GLRenderBufferPtr; Than I define a function accepting both GLTexturePtr and GLRenderBufferPtr : void attachTarget(GLTexturePtr aTexture); void attachTarget(GLRenderBufferPtr aBuffer); invoking <code>attach(new GLTexture)</code> leads to an error: ambiguous function call. The reason is in the contructor of intrusive_ptr: template<class U> intrusive_ptr(intrusive_ptr<U> const & rhs) ... which allows an invocation with an unrelated pointer. Changing the constructor to template<class U> intrusive_ptr( intrusive_ptr<U> const & rhs, typename enable_if<boost::is_convertible<typename boost::add_const<U*>::type, typename boost::add_const<T*>::type >
::type* dummy = NULL )
resolves the problem. I think this is a bug. Best, Stefan