id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
9856	[windows] condition_variable::wait_for returns wrong cv_status on timeout.	pi88el@…	Niall Douglas	"'''The following bug seems to work on *nix systems. But not on Windows 7 with Visual Studio 2013 Express.'''[[BR]]
If a condition variable is waiting for a defined amount of time, sometimes (nearly always) the returned cv_status is wrong.

{{{
int main() {
    mutex mtx;
    condition_variable cond;
    
    unique_lock<mutex> lk(mtx);
    
    std::cout << BOOST_VERSION << ""\n"";
    
    for(int i=0; i<10; i++) {
        std::cout << i << "" : "" << chrono::steady_clock::now() << ""\n"";
        if (cv_status::no_timeout == cond.wait_for(lk, chrono::seconds(1)))
            std::cout << ""no_timeout\n"";
    }
}
}}}

While the condition is '''never''' notified, i get '''no_timeout'''.[[BR]]

debuging the code:

{{{
steady_clock::time_point c_now = steady_clock::now();
do_wait(lock, ceil<milliseconds>(d).count());
return steady_clock::now() - c_now < d ? cv_status::no_timeout :
                                         cv_status::timeout;
}}}

'''steady_clock::now() - c_now < d''' is ''true''. It seems do_wait is sleeping to short.
"	Bugs	closed		thread	Boost 1.57.0	Problem	wontfix	condition_variable wait_for cv_status