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 
11 // <condition_variable>
12 
13 // class condition_variable_any;
14 
15 // void notify_all();
16 
17 #include <condition_variable>
18 #include <mutex>
19 #include <thread>
20 #include <vector>
21 #include <atomic>
22 #include <cassert>
23 
24 #include "make_test_thread.h"
25 #include "test_macros.h"
26 
27 std::condition_variable_any cv;
28 
29 typedef std::timed_mutex L0;
30 typedef std::unique_lock<L0> L1;
31 
32 L0 m0;
33 
34 const unsigned threadCount = 2;
35 bool pleaseExit = false;
36 std::atomic<unsigned> notReady;
37 
helper()38 void helper() {
39   L1 lk(m0);
40   --notReady;
41   while (pleaseExit == false)
42     cv.wait(lk);
43 }
44 
main(int,char **)45 int main(int, char**)
46 {
47   notReady = threadCount;
48   std::vector<std::thread> threads(threadCount);
49   for (unsigned i = 0; i < threadCount; i++)
50     threads[i] = support::make_test_thread(helper);
51   {
52     while (notReady > 0)
53       std::this_thread::yield();
54     // At this point, both threads have had a chance to acquire the lock and are
55     // either waiting on the condition variable or about to wait.
56     L1 lk(m0);
57     pleaseExit = true;
58     // POSIX does not guarantee reliable scheduling if notify_all is called
59     // without the lock being held.
60     cv.notify_all();
61   }
62   // The test will hang if not all of the threads were woken.
63   for (unsigned i = 0; i < threadCount; i++)
64     threads[i].join();
65 
66   return 0;
67 }
68