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