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++03, c++98, c++11
12 
13 // <shared_mutex>
14 
15 // class shared_timed_mutex;
16 
17 // void lock();
18 
19 #include <shared_mutex>
20 #include <thread>
21 #include <cstdlib>
22 #include <cassert>
23 
24 #include "test_macros.h"
25 
26 std::shared_timed_mutex m;
27 
28 typedef std::chrono::system_clock Clock;
29 typedef Clock::time_point time_point;
30 typedef Clock::duration duration;
31 typedef std::chrono::milliseconds ms;
32 typedef std::chrono::nanoseconds ns;
33 
34 
35 ms WaitTime = ms(250);
36 
37 // Thread sanitizer causes more overhead and will sometimes cause this test
38 // to fail. To prevent this we give Thread sanitizer more time to complete the
39 // test.
40 #if !TEST_HAS_FEATURE(thread_sanitizer)
41 ms Tolerance = ms(50);
42 #else
43 ms Tolerance = ms(100);
44 #endif
45 
46 
47 void f()
48 {
49     time_point t0 = Clock::now();
50     m.lock();
51     time_point t1 = Clock::now();
52     m.unlock();
53     ns d = t1 - t0 - ms(250);
54     assert(d < ms(50));  // within 50ms
55 }
56 
57 int main()
58 {
59     m.lock();
60     std::thread t(f);
61     std::this_thread::sleep_for(ms(250));
62     m.unlock();
63     t.join();
64 }
65