Update boost to 1.71 and add asio

boost/asio/handler_alloc_hook.hpp

@@ -0,0 +1,83 @@
+//
+// handler_alloc_hook.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2019 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 BOOST_ASIO_HANDLER_ALLOC_HOOK_HPP
+#define BOOST_ASIO_HANDLER_ALLOC_HOOK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <boost/asio/detail/config.hpp>
+#include <cstddef>
+
+#include <boost/asio/detail/push_options.hpp>
+
+namespace boost {
+namespace asio {
+
+/// Default allocation function for handlers.
+/**
+ * Asynchronous operations may need to allocate temporary objects. Since
+ * asynchronous operations have a handler function object, these temporary
+ * objects can be said to be associated with the handler.
+ *
+ * Implement asio_handler_allocate and asio_handler_deallocate for your own
+ * handlers to provide custom allocation for these temporary objects.
+ *
+ * The default implementation of these allocation hooks uses <tt>::operator
+ * new</tt> and <tt>::operator delete</tt>.
+ *
+ * @note All temporary objects associated with a handler will be deallocated
+ * before the upcall to the handler is performed. This allows the same memory to
+ * be reused for a subsequent asynchronous operation initiated by the handler.
+ *
+ * @par Example
+ * @code
+ * class my_handler;
+ *
+ * void* asio_handler_allocate(std::size_t size, my_handler* context)
+ * {
+ *   return ::operator new(size);
+ * }
+ *
+ * void asio_handler_deallocate(void* pointer, std::size_t size,
+ *     my_handler* context)
+ * {
+ *   ::operator delete(pointer);
+ * }
+ * @endcode
+ */
+BOOST_ASIO_DECL void* asio_handler_allocate(
+    std::size_t size, ...);
+
+/// Default deallocation function for handlers.
+/**
+ * Implement asio_handler_allocate and asio_handler_deallocate for your own
+ * handlers to provide custom allocation for the associated temporary objects.
+ *
+ * The default implementation of these allocation hooks uses <tt>::operator
+ * new</tt> and <tt>::operator delete</tt>.
+ *
+ * @sa asio_handler_allocate.
+ */
+BOOST_ASIO_DECL void asio_handler_deallocate(
+    void* pointer, std::size_t size, ...);
+
+} // namespace asio
+} // namespace boost
+
+#include <boost/asio/detail/pop_options.hpp>
+
+#if defined(BOOST_ASIO_HEADER_ONLY)
+# include <boost/asio/impl/handler_alloc_hook.ipp>
+#endif // defined(BOOST_ASIO_HEADER_ONLY)
+
+#endif // BOOST_ASIO_HANDLER_ALLOC_HOOK_HPP