1//
2// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
3// See https://llvm.org/LICENSE.txt for license information.
4// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
5//
6//===----------------------------------------------------------------------===//
7
8// UNSUPPORTED: c++03, c++11, c++14, c++17
9// UNSUPPORTED: no-threads
10// XFAIL: availability-synchronization_library-missing
11// XFAIL: !has-64-bit-atomics
12// XFAIL: !has-1024-bit-atomics
13
14// void notify_all() const noexcept;
15
16#include <atomic>
17#include <cassert>
18#include <thread>
19#include <type_traits>
20#include <vector>
21
22#include "atomic_helpers.h"
23#include "make_test_thread.h"
24#include "test_macros.h"
25
26template <typename T>
27struct TestNotifyAll {
28 void operator()() const {
29 T x(T(1));
30 std::atomic_ref<T> const a(x);
31
32 bool done = false;
33 std::atomic<int> started_num = 0;
34 std::atomic<int> wait_done_num = 0;
35
36 constexpr auto number_of_threads = 8;
37 std::vector<std::thread> threads;
38 threads.reserve(n: number_of_threads);
39
40 for (auto j = 0; j < number_of_threads; ++j) {
41 threads.push_back(support::make_test_thread([&a, &started_num, &done, &wait_done_num] {
42 started_num.fetch_add(1, std::memory_order::relaxed);
43
44 a.wait(T(1));
45 wait_done_num.fetch_add(1, std::memory_order::relaxed);
46
47 // likely to fail if wait did not block
48 assert(done);
49 }));
50 }
51
52 while (started_num.load(std::memory_order::relaxed) != number_of_threads) {
53 std::this_thread::yield();
54 }
55
56 std::this_thread::sleep_for(rtime: std::chrono::milliseconds(1));
57
58 done = true;
59 a.store(T(3));
60 a.notify_all();
61
62 // notify_all should unblock all the threads so that the loop below won't stuck
63 while (wait_done_num.load(std::memory_order::relaxed) != number_of_threads) {
64 std::this_thread::yield();
65 }
66
67 for (auto& thread : threads) {
68 thread.join();
69 }
70
71 ASSERT_NOEXCEPT(a.notify_all());
72 }
73};
74
75int main(int, char**) {
76 TestEachAtomicType<TestNotifyAll>()();
77 return 0;
78}
79

source code of libcxx/test/std/atomics/atomics.ref/notify_all.pass.cpp