chromium/third_party/libc++/src/include/latch

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_LATCH
#define _LIBCPP_LATCH

/*
    latch synopsis

namespace std
{

  class latch                                     // since C++20
  {
  public:
    static constexpr ptrdiff_t max() noexcept;

    constexpr explicit latch(ptrdiff_t __expected);
    ~latch();

    latch(const latch&) = delete;
    latch& operator=(const latch&) = delete;

    void count_down(ptrdiff_t __update = 1);
    bool try_wait() const noexcept;
    void wait() const;
    void arrive_and_wait(ptrdiff_t __update = 1);

  private:
    ptrdiff_t __counter; // exposition only
  };

}

*/

#include <__config>

#if !defined(_LIBCPP_HAS_NO_THREADS)

#  include <__assert>
#  include <__atomic/atomic_base.h>
#  include <__atomic/atomic_sync.h>
#  include <__atomic/memory_order.h>
#  include <cstddef>
#  include <limits>
#  include <version>

#  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#    pragma GCC system_header
#  endif

_LIBCPP_PUSH_MACROS
#  include <__undef_macros>

#  if _LIBCPP_STD_VER >= 20

_LIBCPP_BEGIN_NAMESPACE_STD

class latch { … };

_LIBCPP_END_NAMESPACE_STD

#  endif // _LIBCPP_STD_VER >= 20

_LIBCPP_POP_MACROS

#endif // !defined(_LIBCPP_HAS_NO_THREADS)

#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
#  include <atomic>
#endif

#endif // _LIBCPP_LATCH