boost::log::thread_access_mode_of<boost::log::aux::shared_lock_guard< MutexT >>
// In header: <boost/log/utility/strictest_lock.hpp> template<typename MutexT> struct thread_access_mode_of<boost::log::aux::shared_lock_guard< MutexT >> : public mpl::integral_c< lock_access_mode, shared_access > { };