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 // void notify_one();
16 
17 #include <condition_variable>
18 #include <atomic>
19 #include <mutex>
20 #include <thread>
21 #include <cassert>
22 
23 #include "test_macros.h"
24 
25 
26 std::condition_variable cv;
27 std::mutex mut;
28 
29 std::atomic_int test1(0);
30 std::atomic_int test2(0);
31 
32 void f1()
33 {
34     std::unique_lock<std::mutex> lk(mut);
35     assert(test1 == 0);
36     while (test1 == 0)
37         cv.wait(lk);
38     assert(test1 == 1);
39     test1 = 2;
40 }
41 
42 void f2()
43 {
44     std::unique_lock<std::mutex> lk(mut);
45     assert(test2 == 0);
46     while (test2 == 0)
47         cv.wait(lk);
48     assert(test2 == 1);
49     test2 = 2;
50 }
51 
52 int main(int, char**)
53 {
54     std::thread t1(f1);
55     std::thread t2(f2);
56     std::this_thread::sleep_for(std::chrono::milliseconds(100));
57     {
58         std::unique_lock<std::mutex>lk(mut);
59         test1 = 1;
60         test2 = 1;
61     }
62     cv.notify_one();
63     {
64         std::this_thread::sleep_for(std::chrono::milliseconds(100));
65         std::unique_lock<std::mutex>lk(mut);
66     }
67     if (test1 == 2)
68     {
69         assert(test2 == 1);
70         t1.join();
71         test1 = 0;
72     }
73     else if (test2 == 2)
74     {
75         assert(test1 == 1);
76         t2.join();
77         test2 = 0;
78     }
79     else
80         assert(false);
81     cv.notify_one();
82     {
83         std::this_thread::sleep_for(std::chrono::milliseconds(100));
84         std::unique_lock<std::mutex>lk(mut);
85     }
86     if (test1 == 2)
87     {
88         assert(test2 == 0);
89         t1.join();
90         test1 = 0;
91     }
92     else if (test2 == 2)
93     {
94         assert(test1 == 0);
95         t2.join();
96         test2 = 0;
97     }
98     else
99         assert(false);
100 
101   return 0;
102 }
103