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: no-threads
10 // ALLOW_RETRIES: 2
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 #include "make_test_thread.h"
29 #include "test_macros.h"
30 
31 class Pred
32 {
33     int& i_;
34 public:
35     explicit Pred(int& i) : i_(i) {}
36 
37     bool operator()() {return i_ != 0;}
38 };
39 
40 std::condition_variable cv;
41 std::mutex mut;
42 
43 int test1 = 0;
44 int test2 = 0;
45 
46 int runs = 0;
47 
48 void f()
49 {
50     typedef std::chrono::system_clock Clock;
51     typedef std::chrono::milliseconds milliseconds;
52     std::unique_lock<std::mutex> lk(mut);
53     assert(test2 == 0);
54     test1 = 1;
55     cv.notify_one();
56     Clock::time_point t0 = Clock::now();
57     bool r = cv.wait_for(lk, milliseconds(250), Pred(test2));
58     ((void)r); // Prevent unused warning
59     Clock::time_point t1 = Clock::now();
60     if (runs == 0)
61     {
62         assert(t1 - t0 < milliseconds(250));
63         assert(test2 != 0);
64     }
65     else
66     {
67         assert(t1 - t0 - milliseconds(250) < milliseconds(50));
68         assert(test2 == 0);
69     }
70     ++runs;
71 }
72 
73 int main(int, char**)
74 {
75     {
76         std::unique_lock<std::mutex>lk(mut);
77         std::thread t = support::make_test_thread(f);
78         assert(test1 == 0);
79         while (test1 == 0)
80             cv.wait(lk);
81         assert(test1 != 0);
82         test2 = 1;
83         lk.unlock();
84         cv.notify_one();
85         t.join();
86     }
87     test1 = 0;
88     test2 = 0;
89     {
90         std::unique_lock<std::mutex>lk(mut);
91         std::thread t = support::make_test_thread(f);
92         assert(test1 == 0);
93         while (test1 == 0)
94             cv.wait(lk);
95         assert(test1 != 0);
96         lk.unlock();
97         t.join();
98     }
99 
100   return 0;
101 }
102