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 <__threading_support> 21 22#if !defined(_LIBCPP_HAS_NO_THREADS) 23# if _LIBCPP_ABI_VERSION == 1 || !defined(_LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION) 24# define NEEDS_MUTEX_DESTRUCTOR 25# endif 26#endif 27 28_LIBCPP_BEGIN_NAMESPACE_STD 29 30#ifdef NEEDS_MUTEX_DESTRUCTOR 31class _LIBCPP_TYPE_VIS mutex 32{ 33 __libcpp_mutex_t __m_ = _LIBCPP_MUTEX_INITIALIZER; 34 35public: 36 _LIBCPP_ALWAYS_INLINE _LIBCPP_INLINE_VISIBILITY 37 constexpr mutex() = default; 38 mutex(const mutex&) = delete; 39 mutex& operator=(const mutex&) = delete; 40 ~mutex() noexcept; 41}; 42 43 44mutex::~mutex() noexcept 45{ 46 __libcpp_mutex_destroy(&__m_); 47} 48 49#endif // !_LIBCPP_HAS_NO_THREADS 50_LIBCPP_END_NAMESPACE_STD 51