[Boost-users] [Thread][win32, msvc] Mutexes

Hi I consider changing from win32 CRITICAL_SECTIONs to Boost.Thread mutexes. boost::mutex isn't CRITICAL_SECTION, but boost::detail::lightweight_mutex is. Does this mean that boost::mutex is heavy-weight ? If so, what's the reason for heavy-weight implementation which has the same capabilities that lightweight CRITICAL_SECTION has ? If not so, what's the reason for boost::detail::lightweight_mutex to exist ? Thanks.