title: intrusive_ptr in c++11
body: <p>Does C++11 have something equivalent to <code>boost::intrusive_ptr</code>? </p>
  
  <p>My problem is that I have a C-style interface over my C++ code. Both sides of the interface can use C++, but exposing the C interface is required for compatibility reasons. I cannot use <code>std::shared_ptr</code> because I have to manage the object through two (or more) smart pointers. I am unable to figure out a solution with something like <code>boost::intrusive_ptr</code>.</p>