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// Define ~mutex.
10//
11// On some platforms ~mutex has been made trivial and the definition is only
12// provided for ABI compatibility.
13//
14// In order to avoid ODR violations within libc++ itself, we need to ensure
15// that *nothing* sees the non-trivial mutex declaration. For this reason
16// we re-declare the entire class in this file instead of using
17// _LIBCPP_BUILDING_LIBRARY to change the definition in the headers.
18
19#include <__config>
20#include <__thread/support.h>
21
22#if _LIBCPP_ABI_VERSION == 1 || !_LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION
23#  define NEEDS_MUTEX_DESTRUCTOR
24#endif
25
26_LIBCPP_BEGIN_NAMESPACE_STD
27
28#ifdef NEEDS_MUTEX_DESTRUCTOR
29class _LIBCPP_EXPORTED_FROM_ABI mutex {
30  __libcpp_mutex_t __m_ = _LIBCPP_MUTEX_INITIALIZER;
31
32public:
33  _LIBCPP_ALWAYS_INLINE _LIBCPP_HIDE_FROM_ABI constexpr mutex() = default;
34  mutex(const mutex&)                                           = delete;
35  mutex& operator=(const mutex&)                                = delete;
36  ~mutex() noexcept;
37};
38
39mutex::~mutex() noexcept { __libcpp_mutex_destroy(&__m_); }
40#endif // !NEEDS_MUTEX_DESTRUCTOR
41
42_LIBCPP_END_NAMESPACE_STD