https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77704
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2016-09-23 Summary|Data race on std::regex |Data race on std::cype Ever confirmed|0 |1 Severity|major |normal --- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- Ugh, we have mutable members in std::ctype<char> #include <locale> #include <thread> int main() { auto& ctype = std::use_facet<std::ctype<char>>(std::locale::classic()); auto f = [&]{ for (int i = 0; i < 64; ++i) ctype.narrow(i, 'a'); }; std::thread t1{f}; std::thread t2{f}; t1.join(); t2.join(); }