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 // XFAIL: dylib-has-no-shared_mutex
12 
13 // ALLOW_RETRIES: 2
14 
15 // <shared_mutex>
16 
17 // template <class Mutex> class shared_lock;
18 
19 // void lock();
20 
21 #include <shared_mutex>
22 #include <thread>
23 #include <vector>
24 #include <cstdlib>
25 #include <cassert>
26 
27 #include "test_macros.h"
28 
29 std::shared_timed_mutex m;
30 
31 typedef std::chrono::system_clock Clock;
32 typedef Clock::time_point time_point;
33 typedef Clock::duration duration;
34 typedef std::chrono::milliseconds ms;
35 typedef std::chrono::nanoseconds ns;
36 
37 ms WaitTime = ms(250);
38 
39 // Thread sanitizer causes more overhead and will sometimes cause this test
40 // to fail. To prevent this we give Thread sanitizer more time to complete the
41 // test.
42 #if !defined(TEST_HAS_SANITIZERS)
43 ms Tolerance = ms(25);
44 #else
45 ms Tolerance = ms(25 * 5);
46 #endif
47 
48 
49 void f()
50 {
51     std::shared_lock<std::shared_timed_mutex> lk(m, std::defer_lock);
52     time_point t0 = Clock::now();
53     lk.lock();
54     time_point t1 = Clock::now();
55     assert(lk.owns_lock() == true);
56     ns d = t1 - t0 - WaitTime;
57     assert(d < Tolerance);  // within tolerance
58 #ifndef TEST_HAS_NO_EXCEPTIONS
59     try
60     {
61         lk.lock();
62         assert(false);
63     }
64     catch (std::system_error& e)
65     {
66         assert(e.code().value() == EDEADLK);
67     }
68 #endif
69     lk.unlock();
70     lk.release();
71 #ifndef TEST_HAS_NO_EXCEPTIONS
72     try
73     {
74         lk.lock();
75         assert(false);
76     }
77     catch (std::system_error& e)
78     {
79         assert(e.code().value() == EPERM);
80     }
81 #endif
82 }
83 
84 int main(int, char**)
85 {
86     m.lock();
87     std::vector<std::thread> v;
88     for (int i = 0; i < 5; ++i)
89         v.push_back(std::thread(f));
90     std::this_thread::sleep_for(WaitTime);
91     m.unlock();
92     for (auto& t : v)
93         t.join();
94 
95   return 0;
96 }
97