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 // <mutex>
11 
12 // template <class Mutex> class unique_lock;
13 
14 // void swap(unique_lock& u);
15 
16 #include <mutex>
17 #include <cassert>
18 
19 struct mutex
20 {
lockmutex21     void lock() {}
unlockmutex22     void unlock() {}
23 };
24 
25 mutex m;
26 
main()27 int main()
28 {
29     std::unique_lock<mutex> lk1(m);
30     std::unique_lock<mutex> lk2;
31     lk1.swap(lk2);
32     assert(lk1.mutex() == nullptr);
33     assert(lk1.owns_lock() == false);
34     assert(lk2.mutex() == &m);
35     assert(lk2.owns_lock() == true);
36 }
37