https://svn.boost.org/trac10/ticket/10457 <p> boost/locale/date_time.hpp: warning C4512: 'boost::locale::date_time_duration' : assignment operator could not be generated </p> <p> This is generated with MSVC12 warning level 4. Compiling with treat warnings as error is problematic. </p> <p> The fix is simple, just add a deleted assignment operator: </p> <pre class="wiki"> /// Get ending point /// date_time const &amp;end() const { return e_; } #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1800)) // prevent warning C4512: assignment operator could not be generated BOOST_DELETED_FUNCTION(date_time_duration&amp; operator=(date_time_duration const&amp;)) #endif private: date_time const &amp;s_; date_time const &amp;e_; </pre> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/10457 Trac 1.4.3