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 // UNSUPPORTED: libcpp-has-no-threads 11 12 // <thread> 13 14 // template <class Rep, class Period> 15 // void sleep_for(const chrono::duration<Rep, Period>& rel_time); 16 17 #include <thread> 18 #include <cstdlib> 19 #include <cassert> 20 #include <signal.h> 21 #include <sys/time.h> 22 23 int main() 24 { 25 int ec; 26 struct sigaction action; 27 action.sa_handler = [](int) {}; 28 sigemptyset(&action.sa_mask); 29 action.sa_flags = 0; 30 31 ec = sigaction(SIGALRM, &action, nullptr); 32 assert(!ec); 33 34 struct itimerval it; 35 it.it_interval = { 0 }; 36 it.it_value.tv_sec = 0; 37 it.it_value.tv_usec = 250000; 38 // This will result in a SIGALRM getting fired resulting in the nanosleep 39 // inside sleep_for getting EINTR. 40 ec = setitimer(ITIMER_REAL, &it, nullptr); 41 assert(!ec); 42 43 typedef std::chrono::system_clock Clock; 44 typedef Clock::time_point time_point; 45 typedef Clock::duration duration; 46 std::chrono::milliseconds ms(500); 47 time_point t0 = Clock::now(); 48 std::this_thread::sleep_for(ms); 49 time_point t1 = Clock::now(); 50 std::chrono::nanoseconds ns = (t1 - t0) - ms; 51 std::chrono::nanoseconds err = 5 * ms / 100; 52 // The time slept is within 5% of 500ms 53 assert(std::abs(ns.count()) < err.count()); 54 } 55
