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++98, c++03, c++11
11 
12 // ALLOW_RETRIES: 2
13 
14 // shared_timed_mutex was introduced in macosx10.12
15 // UNSUPPORTED: with_system_cxx_lib=macosx10.11
16 // UNSUPPORTED: with_system_cxx_lib=macosx10.10
17 // UNSUPPORTED: with_system_cxx_lib=macosx10.9
18 
19 // <shared_mutex>
20 
21 // class shared_timed_mutex;
22 
23 // void lock_shared();
24 
25 #include <shared_mutex>
26 #include <thread>
27 #include <vector>
28 #include <cstdlib>
29 #include <cassert>
30 
31 #include "test_macros.h"
32 
33 std::shared_timed_mutex m;
34 
35 typedef std::chrono::system_clock Clock;
36 typedef Clock::time_point time_point;
37 typedef Clock::duration duration;
38 typedef std::chrono::milliseconds ms;
39 typedef std::chrono::nanoseconds ns;
40 
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 
54 void f()
55 {
56     time_point t0 = Clock::now();
57     m.lock_shared();
58     time_point t1 = Clock::now();
59     m.unlock_shared();
60     ns d = t1 - t0 - WaitTime;
61     assert(d < Tolerance);  // within tolerance
62 }
63 
64 void g()
65 {
66     time_point t0 = Clock::now();
67     m.lock_shared();
68     time_point t1 = Clock::now();
69     m.unlock_shared();
70     ns d = t1 - t0;
71     assert(d < Tolerance);  // within tolerance
72 }
73 
74 
75 int main(int, char**)
76 {
77     m.lock();
78     std::vector<std::thread> v;
79     for (int i = 0; i < 5; ++i)
80         v.push_back(std::thread(f));
81     std::this_thread::sleep_for(WaitTime);
82     m.unlock();
83     for (auto& t : v)
84         t.join();
85     m.lock_shared();
86     for (auto& t : v)
87         t = std::thread(g);
88     std::thread q(f);
89     std::this_thread::sleep_for(WaitTime);
90     m.unlock_shared();
91     for (auto& t : v)
92         t.join();
93     q.join();
94 
95   return 0;
96 }
97