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 // template <class Predicate>
16 //   void wait(unique_lock<mutex>& lock, Predicate pred);
17 
18 #include <condition_variable>
19 #include <mutex>
20 #include <thread>
21 #include <functional>
22 #include <cassert>
23 
24 #include "test_macros.h"
25 
26 std::condition_variable cv;
27 std::mutex mut;
28 
29 int test1 = 0;
30 int test2 = 0;
31 
32 class Pred
33 {
34     int& i_;
35 public:
36     explicit Pred(int& i) : i_(i) {}
37 
38     bool operator()() {return i_ != 0;}
39 };
40 
41 void f()
42 {
43     std::unique_lock<std::mutex> lk(mut);
44     assert(test2 == 0);
45     test1 = 1;
46     cv.notify_one();
47     cv.wait(lk, Pred(test2));
48     assert(test2 != 0);
49 }
50 
51 int main(int, char**)
52 {
53     std::unique_lock<std::mutex>lk(mut);
54     std::thread t(f);
55     assert(test1 == 0);
56     while (test1 == 0)
57         cv.wait(lk);
58     assert(test1 != 0);
59     test2 = 1;
60     lk.unlock();
61     cv.notify_one();
62     t.join();
63 
64   return 0;
65 }
66