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 _LIBCPP_ABI_VERSION == 1 || !defined(_LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION) 23 # define NEEDS_MUTEX_DESTRUCTOR 24 #endif 25 26 _LIBCPP_BEGIN_NAMESPACE_STD 27 28 #ifdef NEEDS_MUTEX_DESTRUCTOR 29 class _LIBCPP_EXPORTED_FROM_ABI mutex { 30 __libcpp_mutex_t __m_ = _LIBCPP_MUTEX_INITIALIZER; 31 32 public: 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 39 mutex::~mutex() noexcept { __libcpp_mutex_destroy(&__m_); } 40 #endif // !NEEDS_MUTEX_DESTRUCTOR 41 42 _LIBCPP_END_NAMESPACE_STD 43