title: The future of C++ alignment: passing by value?
body: <p>Reading the Eigen library documentation, I noticed that <a href="http://eigen.tuxfamily.org/dox/TopicPassingByValue.html" rel="noreferrer">some objects cannot be passed by value</a>.  Are there any developments in C++11 or planned developments that will make it safe to pass such objects by value?</p>
  
  <p>Also, why is there no problem with returning such objects by value?</p>