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 swap(unique_lock& u);
17
18#include <mutex>
19#include <cassert>
20
21struct mutex
22{
23    void lock() {}
24    void unlock() {}
25};
26
27mutex m;
28
29int main()
30{
31    std::unique_lock<mutex> lk1(m);
32    std::unique_lock<mutex> lk2;
33    lk1.swap(lk2);
34    assert(lk1.mutex() == nullptr);
35    assert(lk1.owns_lock() == false);
36    assert(lk2.mutex() == &m);
37    assert(lk2.owns_lock() == true);
38}
39