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// mutex_type *mutex() const;
15
16#include <mutex>
17#include <cassert>
18
19std::mutex m;
20
21int main()
22{
23    std::unique_lock<std::mutex> lk0;
24    assert(lk0.mutex() == nullptr);
25    std::unique_lock<std::mutex> lk1(m);
26    assert(lk1.mutex() == &m);
27    lk1.unlock();
28    assert(lk1.mutex() == &m);
29}
30