1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // UNSUPPORTED: libcpp-has-no-threads
11 // UNSUPPORTED: c++98, c++03, c++11
12 
13 // <shared_mutex>
14 
15 // class timed_mutex;
16 
17 // template <class Rep, class Period>
18 //   shared_lock(mutex_type& m, const chrono::duration<Rep, Period>& rel_time);
19 
20 #include <shared_mutex>
21 #include <thread>
22 #include <vector>
23 #include <cstdlib>
24 #include <cassert>
25 
26 #include "test_macros.h"
27 
28 std::shared_timed_mutex m;
29 
30 typedef std::chrono::steady_clock Clock;
31 typedef Clock::time_point time_point;
32 typedef Clock::duration duration;
33 typedef std::chrono::milliseconds ms;
34 typedef std::chrono::nanoseconds ns;
35 
36 ms WaitTime = ms(250);
37 
38 // Thread sanitizer causes more overhead and will sometimes cause this test
39 // to fail. To prevent this we give Thread sanitizer more time to complete the
40 // test.
41 #if !TEST_HAS_FEATURE(thread_sanitizer)
42 ms Tolerance = ms(50);
43 #else
44 ms Tolerance = ms(100);
45 #endif
46 
47 
48 void f1()
49 {
50     time_point t0 = Clock::now();
51     std::shared_lock<std::shared_timed_mutex> lk(m, WaitTime + Tolerance);
52     assert(lk.owns_lock() == true);
53     time_point t1 = Clock::now();
54     ns d = t1 - t0 - WaitTime;
55     assert(d < Tolerance);  // within 50ms
56 }
57 
58 void f2()
59 {
60     time_point t0 = Clock::now();
61     std::shared_lock<std::shared_timed_mutex> lk(m, WaitTime);
62     assert(lk.owns_lock() == false);
63     time_point t1 = Clock::now();
64     ns d = t1 - t0 - WaitTime;
65     assert(d < Tolerance);  // within 50ms
66 }
67 
68 int main()
69 {
70     {
71         m.lock();
72         std::vector<std::thread> v;
73         for (int i = 0; i < 5; ++i)
74             v.push_back(std::thread(f1));
75         std::this_thread::sleep_for(WaitTime);
76         m.unlock();
77         for (auto& t : v)
78             t.join();
79     }
80     {
81         m.lock();
82         std::vector<std::thread> v;
83         for (int i = 0; i < 5; ++i)
84             v.push_back(std::thread(f2));
85         std::this_thread::sleep_for(WaitTime + Tolerance);
86         m.unlock();
87         for (auto& t : v)
88             t.join();
89     }
90 }
91