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 
12 // dylib support for shared_mutex was added in macosx10.12
13 // XFAIL: with_system_cxx_lib=macosx10.11
14 // XFAIL: with_system_cxx_lib=macosx10.10
15 // XFAIL: with_system_cxx_lib=macosx10.9
16 
17 // ALLOW_RETRIES: 2
18 
19 // <shared_mutex>
20 
21 // template <class Mutex> class shared_lock;
22 
23 // explicit shared_lock(mutex_type& m);
24 
25 // template<class _Mutex> shared_lock(shared_lock<_Mutex>)
26 //     -> shared_lock<_Mutex>;  // C++17
27 
28 #include <shared_mutex>
29 #include <thread>
30 #include <vector>
31 #include <cstdlib>
32 #include <cassert>
33 
34 #include "test_macros.h"
35 
36 typedef std::chrono::system_clock Clock;
37 typedef Clock::time_point time_point;
38 typedef Clock::duration duration;
39 typedef std::chrono::milliseconds ms;
40 typedef std::chrono::nanoseconds ns;
41 
42 ms WaitTime = ms(250);
43 
44 // Thread sanitizer causes more overhead and will sometimes cause this test
45 // to fail. To prevent this we give Thread sanitizer more time to complete the
46 // test.
47 #if !defined(TEST_HAS_SANITIZERS)
48 ms Tolerance = ms(50);
49 #else
50 ms Tolerance = ms(50 * 5);
51 #endif
52 
53 std::shared_timed_mutex m;
54 
55 void f()
56 {
57     time_point t0 = Clock::now();
58     time_point t1;
59     {
60     std::shared_lock<std::shared_timed_mutex> ul(m);
61     t1 = Clock::now();
62     }
63     ns d = t1 - t0 - WaitTime;
64     assert(d < Tolerance);  // within tolerance
65 }
66 
67 void g()
68 {
69     time_point t0 = Clock::now();
70     time_point t1;
71     {
72     std::shared_lock<std::shared_timed_mutex> ul(m);
73     t1 = Clock::now();
74     }
75     ns d = t1 - t0;
76     assert(d < Tolerance);  // within tolerance
77 }
78 
79 int main(int, char**)
80 {
81     std::vector<std::thread> v;
82     {
83         m.lock();
84         for (int i = 0; i < 5; ++i)
85             v.push_back(std::thread(f));
86         std::this_thread::sleep_for(WaitTime);
87         m.unlock();
88         for (auto& t : v)
89             t.join();
90     }
91     {
92         m.lock_shared();
93         for (auto& t : v)
94             t = std::thread(g);
95         std::thread q(f);
96         std::this_thread::sleep_for(WaitTime);
97         m.unlock_shared();
98         for (auto& t : v)
99             t.join();
100         q.join();
101     }
102 
103 #ifdef __cpp_deduction_guides
104     std::shared_lock sl(m);
105     static_assert((std::is_same<decltype(sl), std::shared_lock<decltype(m)>>::value), "" );
106 #endif
107 
108   return 0;
109 }
110