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 // <condition_variable> 11 12 // class condition_variable; 13 14 // template <class Clock, class Duration, class Predicate> 15 // bool 16 // wait_until(unique_lock<mutex>& lock, 17 // const chrono::time_point<Clock, Duration>& abs_time, 18 // Predicate pred); 19 20 #include <condition_variable> 21 #include <mutex> 22 #include <thread> 23 #include <chrono> 24 #include <cassert> 25 26 struct Clock 27 { 28 typedef std::chrono::milliseconds duration; 29 typedef duration::rep rep; 30 typedef duration::period period; 31 typedef std::chrono::time_point<Clock> time_point; 32 static const bool is_steady = true; 33 34 static time_point now() 35 { 36 using namespace std::chrono; 37 return time_point(duration_cast<duration>( 38 steady_clock::now().time_since_epoch() 39 )); 40 } 41 }; 42 43 class Pred 44 { 45 int& i_; 46 public: 47 explicit Pred(int& i) : i_(i) {} 48 49 bool operator()() {return i_ != 0;} 50 }; 51 52 std::condition_variable cv; 53 std::mutex mut; 54 55 int test1 = 0; 56 int test2 = 0; 57 58 int runs = 0; 59 60 void f() 61 { 62 std::unique_lock<std::mutex> lk(mut); 63 assert(test2 == 0); 64 test1 = 1; 65 cv.notify_one(); 66 Clock::time_point t0 = Clock::now(); 67 Clock::time_point t = t0 + Clock::duration(250); 68 bool r = cv.wait_until(lk, t, Pred(test2)); 69 Clock::time_point t1 = Clock::now(); 70 if (runs == 0) 71 { 72 assert(t1 - t0 < Clock::duration(250)); 73 assert(test2 != 0); 74 assert(r); 75 } 76 else 77 { 78 assert(t1 - t0 - Clock::duration(250) < Clock::duration(50)); 79 assert(test2 == 0); 80 assert(!r); 81 } 82 ++runs; 83 } 84 85 int main() 86 { 87 { 88 std::unique_lock<std::mutex>lk(mut); 89 std::thread t(f); 90 assert(test1 == 0); 91 while (test1 == 0) 92 cv.wait(lk); 93 assert(test1 != 0); 94 test2 = 1; 95 lk.unlock(); 96 cv.notify_one(); 97 t.join(); 98 } 99 test1 = 0; 100 test2 = 0; 101 { 102 std::unique_lock<std::mutex>lk(mut); 103 std::thread t(f); 104 assert(test1 == 0); 105 while (test1 == 0) 106 cv.wait(lk); 107 assert(test1 != 0); 108 lk.unlock(); 109 t.join(); 110 } 111 } 112