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