Hello, this sample does not compile when using the boost version: #if 1 #include <boost/enable_shared_from_this.hpp> namespace tr1 = boost; #else #include <memory> namespace tr1 = std::tr1; #endif namespace { struct Base { virtual void f() = 0; }; typedef tr1::shared_ptr<Base> BasePtr; struct Sub : public Base, public tr1::enable_shared_from_this<Base> { void f() { BasePtr basePtr = shared_from_this(); } }; } int main() { return 0; } boost\enable_shared_from_this.hpp(50) : error C2446: '==' : no conversion from 'boost::enable_shared_from_this<T> *const ' to '`anonymous-namespace'::Base *' with [ T=`anonymous-namespace'::Base ] Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast boost\enable_shared_from_this.hpp(48) : while compiling class template member function 'boost::shared_ptr<T> boost::enable_shared_from_this<T>::shared_from_this(void)' with [ T=`anonymous-namespace'::Base ] test.cpp(23) : see reference to class template instantiation 'boost::enable_shared_from_this<T>' being compiled with [ T=`anonymous-namespace'::Base ] The tr1 version compiles though. I am using Visual Studio 2008 with SP1 installed. I have already found a workaround, but it is a little bit annoying: struct Sub : public Base, public tr1::enable_shared_from_this<Sub> { void f() { BasePtr basePtr = tr1::dynamic_pointer_cast<Base>(shared_from_this()); } }; I would like to avoid explicit type casts like this. Why does the boost version fail? Thanks in advance! Regards, Daniel Lidström Stockholm, Sweden