chromium/third_party/libc++/src/include/__stop_token/atomic_unique_lock.h

// -*- 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___STOP_TOKEN_ATOMIC_UNIQUE_GUARD_H
#define _LIBCPP___STOP_TOKEN_ATOMIC_UNIQUE_GUARD_H

#include <__bit/popcount.h>
#include <__config>
#include <atomic>

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

_LIBCPP_BEGIN_NAMESPACE_STD

#if _LIBCPP_STD_VER >= 20

// This class implements an RAII unique_lock without a mutex.
// It uses std::atomic<State>,
// where State contains a lock bit and might contain other data,
// and LockedBit is the value of State when the lock bit is set, e.g  1 << 2
template <class _State, _State _LockedBit>
class _LIBCPP_AVAILABILITY_SYNC __atomic_unique_lock { … };

#endif // _LIBCPP_STD_VER >= 20

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___STOP_TOKEN_ATOMIC_UNIQUE_GUARD_H