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 // <mutex>
13 
14 // template <class Mutex> class unique_lock;
15 
16 // void lock();
17 
18 #include <mutex>
19 #include <thread>
20 #include <cstdlib>
21 #include <cassert>
22 
23 std::mutex m;
24 
25 typedef std::chrono::system_clock Clock;
26 typedef Clock::time_point time_point;
27 typedef Clock::duration duration;
28 typedef std::chrono::milliseconds ms;
29 typedef std::chrono::nanoseconds ns;
30 
f()31 void f()
32 {
33     std::unique_lock<std::mutex> lk(m, std::defer_lock);
34     time_point t0 = Clock::now();
35     lk.lock();
36     time_point t1 = Clock::now();
37     assert(lk.owns_lock() == true);
38     ns d = t1 - t0 - ms(250);
39     assert(d < ms(25));  // within 25ms
40     try
41     {
42         lk.lock();
43         assert(false);
44     }
45     catch (std::system_error& e)
46     {
47         assert(e.code().value() == EDEADLK);
48     }
49     lk.unlock();
50     lk.release();
51     try
52     {
53         lk.lock();
54         assert(false);
55     }
56     catch (std::system_error& e)
57     {
58         assert(e.code().value() == EPERM);
59     }
60 }
61 
main()62 int main()
63 {
64     m.lock();
65     std::thread t(f);
66     std::this_thread::sleep_for(ms(250));
67     m.unlock();
68     t.join();
69 }
70