1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 // <thread> 11 12 // template <class Rep, class Period> 13 // void sleep_for(const chrono::duration<Rep, Period>& rel_time); 14 15 #include <thread> 16 #include <cstdlib> 17 #include <cassert> 18 #include <signal.h> 19 #include <sys/time.h> 20 main()21int main() 22 { 23 int ec; 24 struct sigaction action; 25 action.sa_handler = [](int) {}; 26 sigemptyset(&action.sa_mask); 27 action.sa_flags = 0; 28 29 ec = sigaction(SIGALRM, &action, nullptr); 30 assert(!ec); 31 32 struct itimerval it; 33 it.it_interval = { 0 }; 34 it.it_value.tv_sec = 0; 35 it.it_value.tv_usec = 250000; 36 // This will result in a SIGALRM getting fired resulting in the nanosleep 37 // inside sleep_for getting EINTR. 38 ec = setitimer(ITIMER_REAL, &it, nullptr); 39 assert(!ec); 40 41 typedef std::chrono::system_clock Clock; 42 typedef Clock::time_point time_point; 43 typedef Clock::duration duration; 44 std::chrono::milliseconds ms(500); 45 time_point t0 = Clock::now(); 46 std::this_thread::sleep_for(ms); 47 time_point t1 = Clock::now(); 48 std::chrono::nanoseconds ns = (t1 - t0) - ms; 49 std::chrono::nanoseconds err = 5 * ms / 100; 50 // The time slept is within 5% of 500ms 51 assert(std::abs(ns.count()) < err.count()); 52 } 53