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 // FLAKY_TEST.
13 
14 // <shared_mutex>
15 
16 // class shared_timed_mutex;
17 
18 // void lock();
19 
20 #include <shared_mutex>
21 #include <thread>
22 #include <cstdlib>
23 #include <cassert>
24 
25 #include "test_macros.h"
26 
27 std::shared_timed_mutex m;
28 
29 typedef std::chrono::system_clock Clock;
30 typedef Clock::time_point time_point;
31 typedef Clock::duration duration;
32 typedef std::chrono::milliseconds ms;
33 typedef std::chrono::nanoseconds ns;
34 
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 f()
49 {
50     time_point t0 = Clock::now();
51     m.lock();
52     time_point t1 = Clock::now();
53     m.unlock();
54     ns d = t1 - t0 - ms(250);
55     assert(d < ms(50));  // within 50ms
56 }
57 
58 int main(int, char**)
59 {
60     m.lock();
61     std::thread t(f);
62     std::this_thread::sleep_for(ms(250));
63     m.unlock();
64     t.join();
65 
66   return 0;
67 }
68