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// template <class Mutex>
15//   void swap(unique_lock<Mutex>& x, unique_lock<Mutex>& y);
16
17#include <mutex>
18#include <cassert>
19
20struct mutex
21{
22    void lock() {}
23    void unlock() {}
24};
25
26mutex m;
27
28int main()
29{
30    std::unique_lock<mutex> lk1(m);
31    std::unique_lock<mutex> lk2;
32    swap(lk1, lk2);
33    assert(lk1.mutex() == nullptr);
34    assert(lk1.owns_lock() == false);
35    assert(lk2.mutex() == &m);
36    assert(lk2.owns_lock() == true);
37}
38