Boost
  C++ Libraries
  
  ...one of the most highly
  regarded and expertly designed C++ library projects in the
  world.
 — Herb Sutter and Andrei
  Alexandrescu, C++
  Coding Standards
#include <boost/exception/enable_error_info.hpp>
namespace
boost
    {
    template <class T>
    ---unspecified--- enable_error_info( T const & x );
    }
T must be a class with an accessible no-throw copy constructor as per (15.5.1).
Nothing.