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