libcxx/include/__mutex/mutex.h

   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 #ifndef _LIBCPP___MUTEX_MUTEX_H
  10 #define _LIBCPP___MUTEX_MUTEX_H
  11
  12 #include <__config>
  13 #include <__thread/support.h>
  14 #include <__type_traits/is_nothrow_constructible.h>
  15
  16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  17 #  pragma GCC system_header
  18 #endif
  19
  20 #if _LIBCPP_HAS_THREADS
  21
  22 _LIBCPP_BEGIN_NAMESPACE_STD
  23
  24 class _LIBCPP_EXPORTED_FROM_ABI _LIBCPP_THREAD_SAFETY_ANNOTATION(capability("mutex")) mutex {
  25   __libcpp_mutex_t __m_ = _LIBCPP_MUTEX_INITIALIZER;
  26
  27 public:
  28   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR mutex() = default;
  29
  30   mutex(const mutex&)            = delete;
  31   mutex& operator=(const mutex&) = delete;
  32
  33 #  if _LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION
  34   _LIBCPP_HIDE_FROM_ABI ~mutex() = default;
  35 #  else
  36   ~mutex() _NOEXCEPT;
  37 #  endif
  38
  39   void lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability());
  40   bool try_lock() _NOEXCEPT _LIBCPP_THREAD_SAFETY_ANNOTATION(try_acquire_capability(true));
  41   void unlock() _NOEXCEPT _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability());
  42
  43   typedef __libcpp_mutex_t* native_handle_type;
  44   _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() { return &__m_; }
  45 };
  46
  47 static_assert(is_nothrow_default_constructible<mutex>::value, "the default constructor for std::mutex must be nothrow");
  48
  49 _LIBCPP_END_NAMESPACE_STD
  50
  51 #endif // _LIBCPP_HAS_THREADS
  52
  53 #endif // _LIBCPP___MUTEX_MUTEX_H