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 // bool try_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 void f()
36 {
37     time_point t0 = Clock::now();
38     assert(!m.try_lock());
39     assert(!m.try_lock());
40     assert(!m.try_lock());
41     while(!m.try_lock())
42         ;
43     time_point t1 = Clock::now();
44     m.unlock();
45     ns d = t1 - t0 - ms(250);
46     assert(d < ms(200));  // within 200ms
47 }
48 
49 int main(int, char**)
50 {
51     m.lock();
52     std::thread t(f);
53     std::this_thread::sleep_for(ms(250));
54     m.unlock();
55     t.join();
56 
57   return 0;
58 }
59