http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49894
--- Comment #1 from __vic <d.v.a at ngs dot ru> 2011-07-29 06:28:47 UTC --- class mutex { ::pthread_mutex_t mtx; public: constexpr mutex() : mtx(PTHREAD_MUTEX_INITIALIZER) {} }; Compiles fine... What is the difference?