I think the statement "std::system_error is thrown ... if the mutex is already locked" is wrong. If the mutex is already locked false will be returned. --Bear (talk) 05:02, 8 October 2015 (PDT)
- the actual condition for throwing this exception is
owns == true, I guess the page should be more clear. --Cubbi (talk) 06:14, 8 October 2015 (PDT)