Initial Commit

include/asio/detail/atomic_count.hpp

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+//
+// detail/atomic_count.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_ATOMIC_COUNT_HPP
+#define ASIO_DETAIL_ATOMIC_COUNT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS)
+// Nothing to include.
+#else // !defined(ASIO_HAS_THREADS)
+# include <atomic>
+#endif // !defined(ASIO_HAS_THREADS)
+
+namespace asio {
+namespace detail {
+
+#if !defined(ASIO_HAS_THREADS)
+typedef long atomic_count;
+inline void increment(atomic_count& a, long b) { a += b; }
+inline void decrement(atomic_count& a, long b) { a -= b; }
+inline void ref_count_up(atomic_count& a) { ++a; }
+inline bool ref_count_down(atomic_count& a) { return --a == 0; }
+#else // !defined(ASIO_HAS_THREADS)
+typedef std::atomic<long> atomic_count;
+inline void increment(atomic_count& a, long b) { a += b; }
+inline void decrement(atomic_count& a, long b) { a -= b; }
+
+inline void ref_count_up(atomic_count& a)
+{
+  a.fetch_add(1, std::memory_order_relaxed);
+}
+
+inline bool ref_count_down(atomic_count& a)
+{
+  if (a.fetch_sub(1, std::memory_order_release) == 1)
+  {
+    std::atomic_thread_fence(std::memory_order_acquire);
+    return true;
+  }
+  return false;
+}
+#endif // !defined(ASIO_HAS_THREADS)
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_ATOMIC_COUNT_HPP