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// UNSUPPORTED: c++03, c++11
11
12// <shared_mutex>
13
14// template <class Mutex> class shared_lock;
15
16// explicit shared_lock(mutex_type& m);
17
18// template<class _Mutex> shared_lock(shared_lock<_Mutex>)
19// -> shared_lock<_Mutex>; // C++17
20
21#include <atomic>
22#include <cassert>
23#include <shared_mutex>
24#include <thread>
25#include <type_traits>
26#include <vector>
27
28#include "make_test_thread.h"
29#include "test_macros.h"
30
31struct Monitor {
32 bool lock_shared_called = false;
33 bool unlock_shared_called = false;
34};
35
36struct TrackedMutex {
37 Monitor* monitor = nullptr;
38
39 void lock_shared() {
40 if (monitor != nullptr)
41 monitor->lock_shared_called = true;
42 }
43 void unlock_shared() {
44 if (monitor != nullptr)
45 monitor->unlock_shared_called = true;
46 }
47};
48
49template <class Mutex>
50void test() {
51 // Basic sanity test
52 {
53 Mutex mutex;
54 std::vector<std::thread> threads;
55 std::atomic<bool> ready(false);
56 for (int i = 0; i != 5; ++i) {
57 threads.push_back(support::make_test_thread([&] {
58 while (!ready) {
59 // spin
60 }
61
62 std::shared_lock<Mutex> lock(mutex);
63 assert(lock.owns_lock());
64 }));
65 }
66
67 ready = true;
68 for (auto& t : threads)
69 t.join();
70 }
71
72 // Test CTAD
73 {
74#if TEST_STD_VER >= 17
75 Mutex mutex;
76 std::shared_lock lock(mutex);
77 static_assert(std::is_same<decltype(lock), std::shared_lock<Mutex>>::value);
78#endif
79 }
80}
81
82int main(int, char**) {
83#if TEST_STD_VER >= 17
84 test<std::shared_mutex>();
85#endif
86 test<std::shared_timed_mutex>();
87 test<TrackedMutex>();
88
89 // Use shared_lock with a dummy mutex class that tracks whether each
90 // operation has been called or not.
91 {
92 Monitor monitor;
93 TrackedMutex mutex{.monitor: &monitor};
94
95 std::shared_lock<TrackedMutex> lock(mutex);
96 assert(monitor.lock_shared_called);
97 assert(lock.owns_lock());
98
99 lock.unlock();
100 assert(monitor.unlock_shared_called);
101 }
102
103 return 0;
104}
105

source code of libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp