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 
12 // <shared_mutex>
13 
14 // class shared_timed_mutex;
15 
16 // bool try_lock();
17 
18 #include <shared_mutex>
19 #include <thread>
20 #include <cstdlib>
21 #include <cassert>
22 
23 #if _LIBCPP_STD_VER > 11
24 
25 std::shared_timed_mutex m;
26 
27 typedef std::chrono::system_clock Clock;
28 typedef Clock::time_point time_point;
29 typedef Clock::duration duration;
30 typedef std::chrono::milliseconds ms;
31 typedef std::chrono::nanoseconds ns;
32 
33 void f()
34 {
35     time_point t0 = Clock::now();
36     assert(!m.try_lock());
37     assert(!m.try_lock());
38     assert(!m.try_lock());
39     while(!m.try_lock())
40         ;
41     time_point t1 = Clock::now();
42     m.unlock();
43     ns d = t1 - t0 - ms(250);
44     assert(d < ms(200));  // within 200ms
45 }
46 
47 #endif  // _LIBCPP_STD_VER > 11
48 
49 int main()
50 {
51 #if _LIBCPP_STD_VER > 11
52     m.lock();
53     std::thread t(f);
54     std::this_thread::sleep_for(ms(250));
55     m.unlock();
56     t.join();
57 #endif  // _LIBCPP_STD_VER > 11
58 }
59