1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // UNSUPPORTED: libcpp-has-no-threads 10 // FLAKY_TEST. 11 12 // <thread> 13 14 // template <class Clock, class Duration> 15 // void sleep_until(const chrono::time_point<Clock, Duration>& abs_time); 16 17 #include <thread> 18 #include <cstdlib> 19 #include <cassert> 20 21 int main() 22 { 23 typedef std::chrono::system_clock Clock; 24 typedef Clock::time_point time_point; 25 std::chrono::milliseconds ms(500); 26 time_point t0 = Clock::now(); 27 std::this_thread::sleep_until(t0 + ms); 28 time_point t1 = Clock::now(); 29 std::chrono::nanoseconds ns = (t1 - t0) - ms; 30 std::chrono::nanoseconds err = 5 * ms / 100; 31 // The time slept is within 5% of 500ms 32 assert(std::abs(ns.count()) < err.count()); 33 } 34