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    #include <memory>
 
    struct X
    {
    };
 
    struct Y : X
    {
    };
 
    int main()
    {
        std::shared_ptr<X> pX = std::make_shared<Y>();
        std::shared_ptr<Y> pY = std::dynamic_pointer_cast<Y>(pX);
    }
 

In file included from /usr/include/c++/4.7/memory:87:0,
                 from prog.cpp:1:
/usr/include/c++/4.7/bits/shared_ptr.h: In instantiation of ‘std::shared_ptr<_Tp1> std::dynamic_pointer_cast(const std::shared_ptr<_Tp2>&) [with _Tp = Y; _Tp1 = X]’:
prog.cpp:14:64:   required from here
/usr/include/c++/4.7/bits/shared_ptr.h:450:50: error: cannot dynamic_cast ‘(& __r)->std::shared_ptr<X>::<anonymous>.std::__shared_ptr<_Tp, _Lp>::get<X, (__gnu_cxx::_Lock_policy)2u>()’ (of type ‘struct X*’) to type ‘struct Y*’ (source type is not polymorphic)

Standard output is empty