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 // UNSUPPORTED: c++03, c++11
11 // ALLOW_RETRIES: 2
12 
13 // dylib support for shared_mutex was added in macosx10.12
14 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
15 
16 // <shared_mutex>
17 
18 // template <class Mutex> class shared_lock;
19 
20 // explicit shared_lock(mutex_type& m);
21 
22 // template<class _Mutex> shared_lock(shared_lock<_Mutex>)
23 //     -> shared_lock<_Mutex>;  // C++17
24 
25 #include <shared_mutex>
26 #include <thread>
27 #include <vector>
28 #include <cstdlib>
29 #include <cassert>
30 
31 #include "make_test_thread.h"
32 #include "test_macros.h"
33 
34 typedef std::chrono::system_clock Clock;
35 typedef Clock::time_point time_point;
36 typedef Clock::duration duration;
37 typedef std::chrono::milliseconds ms;
38 typedef std::chrono::nanoseconds ns;
39 
40 ms WaitTime = ms(250);
41 
42 // Thread sanitizer causes more overhead and will sometimes cause this test
43 // to fail. To prevent this we give Thread sanitizer more time to complete the
44 // test.
45 #if !defined(TEST_HAS_SANITIZERS)
46 ms Tolerance = ms(50);
47 #else
48 ms Tolerance = ms(50 * 5);
49 #endif
50 
51 std::shared_timed_mutex m;
52 
53 void f()
54 {
55     time_point t0 = Clock::now();
56     time_point t1;
57     {
58     std::shared_lock<std::shared_timed_mutex> ul(m);
59     t1 = Clock::now();
60     }
61     ns d = t1 - t0 - WaitTime;
62     assert(d < Tolerance);  // within tolerance
63 }
64 
65 void g()
66 {
67     time_point t0 = Clock::now();
68     time_point t1;
69     {
70     std::shared_lock<std::shared_timed_mutex> ul(m);
71     t1 = Clock::now();
72     }
73     ns d = t1 - t0;
74     assert(d < Tolerance);  // within tolerance
75 }
76 
77 int main(int, char**)
78 {
79     std::vector<std::thread> v;
80     {
81         m.lock();
82         for (int i = 0; i < 5; ++i)
83             v.push_back(support::make_test_thread(f));
84         std::this_thread::sleep_for(WaitTime);
85         m.unlock();
86         for (auto& t : v)
87             t.join();
88     }
89     {
90         m.lock_shared();
91         for (auto& t : v)
92             t = support::make_test_thread(g);
93         std::thread q = support::make_test_thread(f);
94         std::this_thread::sleep_for(WaitTime);
95         m.unlock_shared();
96         for (auto& t : v)
97             t.join();
98         q.join();
99     }
100 
101 #if TEST_STD_VER >= 17
102     std::shared_lock sl(m);
103     static_assert((std::is_same<decltype(sl), std::shared_lock<decltype(m)>>::value), "" );
104 #endif
105 
106   return 0;
107 }
108