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// <shared_mutex>
11
12// template <class Mutex> class shared_lock;
13
14// shared_lock(mutex_type& m, try_to_lock_t);
15
16#include <shared_mutex>
17#include <thread>
18#include <vector>
19#include <cstdlib>
20#include <cassert>
21
22#if _LIBCPP_STD_VER > 11
23
24std::shared_timed_mutex m;
25
26typedef std::chrono::system_clock Clock;
27typedef Clock::time_point time_point;
28typedef Clock::duration duration;
29typedef std::chrono::milliseconds ms;
30typedef std::chrono::nanoseconds ns;
31
32void f()
33{
34    time_point t0 = Clock::now();
35    {
36        std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock);
37        assert(lk.owns_lock() == false);
38    }
39    {
40        std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock);
41        assert(lk.owns_lock() == false);
42    }
43    {
44        std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock);
45        assert(lk.owns_lock() == false);
46    }
47    while (true)
48    {
49        std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock);
50        if (lk.owns_lock())
51            break;
52    }
53    time_point t1 = Clock::now();
54    ns d = t1 - t0 - ms(250);
55    assert(d < ms(200));  // within 200ms
56}
57
58#endif  // _LIBCPP_STD_VER > 11
59
60int main()
61{
62#if _LIBCPP_STD_VER > 11
63    m.lock();
64    std::vector<std::thread> v;
65    for (int i = 0; i < 5; ++i)
66        v.push_back(std::thread(f));
67    std::this_thread::sleep_for(ms(250));
68    m.unlock();
69    for (auto& t : v)
70        t.join();
71#endif  // _LIBCPP_STD_VER > 11
72}
73