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 // void wait(unique_lock<mutex>& lock);
17 
18 #include <condition_variable>
19 #include <mutex>
20 #include <thread>
21 #include <cassert>
22 
23 std::condition_variable cv;
24 std::mutex mut;
25 
26 int test1 = 0;
27 int test2 = 0;
28 
f()29 void f()
30 {
31     std::unique_lock<std::mutex> lk(mut);
32     assert(test2 == 0);
33     test1 = 1;
34     cv.notify_one();
35     while (test2 == 0)
36         cv.wait(lk);
37     assert(test2 != 0);
38 }
39 
main()40 int main()
41 {
42     std::unique_lock<std::mutex>lk(mut);
43     std::thread t(f);
44     assert(test1 == 0);
45     while (test1 == 0)
46         cv.wait(lk);
47     assert(test1 != 0);
48     test2 = 1;
49     lk.unlock();
50     cv.notify_one();
51     t.join();
52 }
53