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 // void wait(unique_lock<mutex>& lock);
15 
16 #include <condition_variable>
17 #include <mutex>
18 #include <thread>
19 #include <cassert>
20 
21 std::condition_variable cv;
22 std::mutex mut;
23 
24 int test1 = 0;
25 int test2 = 0;
26 
f()27 void f()
28 {
29     std::unique_lock<std::mutex> lk(mut);
30     assert(test2 == 0);
31     test1 = 1;
32     cv.notify_one();
33     while (test2 == 0)
34         cv.wait(lk);
35     assert(test2 != 0);
36 }
37 
main()38 int main()
39 {
40     std::unique_lock<std::mutex>lk(mut);
41     std::thread t(f);
42     assert(test1 == 0);
43     while (test1 == 0)
44         cv.wait(lk);
45     assert(test1 != 0);
46     test2 = 1;
47     lk.unlock();
48     cv.notify_one();
49     t.join();
50 }
51