handler_alloc_hook.hpp 2.33 KB
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//
// handler_alloc_hook.hpp
// ~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2010 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_HANDLER_ALLOC_HOOK_HPP
#define ASIO_HANDLER_ALLOC_HOOK_HPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include "asio/detail/push_options.hpp"

#include "asio/detail/push_options.hpp"
#include <cstddef>
#include <boost/config.hpp>
#include "asio/detail/pop_options.hpp"

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.
 *
 * This default implementation is simply:
 * @code
 * return ::operator new(size);
 * @endcode
 *
 * @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
 */
inline void* asio_handler_allocate(std::size_t size, ...)
{
  return ::operator new(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.
 *
 * This default implementation is simply:
 * @code
 * ::operator delete(pointer);
 * @endcode
 *
 * @sa asio_handler_allocate.
 */
inline void asio_handler_deallocate(void* pointer, std::size_t size, ...)
{
  (void)(size);
  ::operator delete(pointer);
}

} // namespace asio

#include "asio/detail/pop_options.hpp"

#endif // ASIO_HANDLER_ALLOC_HOOK_HPP