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 // template <class Mutex> class shared_lock;
15 
16 // bool try_lock();
17 
18 #include <shared_mutex>
19 #include <cassert>
20 
21 #if _LIBCPP_STD_VER > 11
22 
23 bool try_lock_called = false;
24 
25 struct mutex
26 {
try_lock_sharedmutex27     bool try_lock_shared()
28     {
29         try_lock_called = !try_lock_called;
30         return try_lock_called;
31     }
unlock_sharedmutex32     void unlock_shared() {}
33 };
34 
35 mutex m;
36 
37 #endif  // _LIBCPP_STD_VER > 11
38 
main()39 int main()
40 {
41 #if _LIBCPP_STD_VER > 11
42     std::shared_lock<mutex> lk(m, std::defer_lock);
43     assert(lk.try_lock() == true);
44     assert(try_lock_called == true);
45     assert(lk.owns_lock() == true);
46     try
47     {
48         lk.try_lock();
49         assert(false);
50     }
51     catch (std::system_error& e)
52     {
53         assert(e.code().value() == EDEADLK);
54     }
55     lk.unlock();
56     assert(lk.try_lock() == false);
57     assert(try_lock_called == false);
58     assert(lk.owns_lock() == false);
59     lk.release();
60     try
61     {
62         lk.try_lock();
63         assert(false);
64     }
65     catch (std::system_error& e)
66     {
67         assert(e.code().value() == EPERM);
68     }
69 #endif  // _LIBCPP_STD_VER > 11
70 }
71