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 <__threading_support>
14 #include <__type_traits/is_nothrow_default_constructible.h>
15 
16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17 #  pragma GCC system_header
18 #endif
19 
20 #ifndef _LIBCPP_HAS_NO_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 defined(_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_NO_THREADS
52 
53 #endif // _LIBCPP___MUTEX_MUTEX_H
54