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: no-threads
10 // UNSUPPORTED: c++03, c++11
11 //
12 // ALLOW_RETRIES: 2
13 
14 // <shared_mutex>
15 
16 // template <class Mutex> class shared_lock;
17 
18 // bool try_lock();
19 
20 #include <shared_mutex>
21 #include <cassert>
22 #include <mutex>
23 
24 #include "test_macros.h"
25 
26 bool try_lock_called = false;
27 
28 struct mutex
29 {
try_lock_sharedmutex30     bool try_lock_shared()
31     {
32         try_lock_called = !try_lock_called;
33         return try_lock_called;
34     }
unlock_sharedmutex35     void unlock_shared() {}
36 };
37 
38 mutex m;
39 
main(int,char **)40 int main(int, char**)
41 {
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 #ifndef TEST_HAS_NO_EXCEPTIONS
47     try
48     {
49         TEST_IGNORE_NODISCARD lk.try_lock();
50         assert(false);
51     }
52     catch (std::system_error& e)
53     {
54         assert(e.code().value() == EDEADLK);
55     }
56 #endif
57     lk.unlock();
58     assert(lk.try_lock() == false);
59     assert(try_lock_called == false);
60     assert(lk.owns_lock() == false);
61     lk.release();
62 #ifndef TEST_HAS_NO_EXCEPTIONS
63     try
64     {
65         TEST_IGNORE_NODISCARD lk.try_lock();
66         assert(false);
67     }
68     catch (std::system_error& e)
69     {
70         assert(e.code().value() == EPERM);
71     }
72 #endif
73 
74   return 0;
75 }
76