Edit: /usr/include/boost/asio/handler_invoke_hook.hpp (3744B)
//
// handler_invoke_hook.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2020 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_INVOKE_HOOK_HPP
#define BOOST_ASIO_HANDLER_INVOKE_HOOK_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include
#include
namespace boost {
namespace asio {
/** @defgroup asio_handler_invoke boost::asio::asio_handler_invoke
*
* @brief (Deprecated: Use the associated_executor trait.) Default invoke
* function for handlers.
*
* Completion handlers for asynchronous operations are invoked by the
* io_context associated with the corresponding object (e.g. a socket or
* deadline_timer). Certain guarantees are made on when the handler may be
* invoked, in particular that a handler can only be invoked from a thread that
* is currently calling @c run() on the corresponding io_context object.
* Handlers may subsequently be invoked through other objects (such as
* io_context::strand objects) that provide additional guarantees.
*
* When asynchronous operations are composed from other asynchronous
* operations, all intermediate handlers should be invoked using the same
* method as the final handler. This is required to ensure that user-defined
* objects are not accessed in a way that may violate the guarantees. This
* hooking function ensures that the invoked method used for the final handler
* is accessible at each intermediate step.
*
* Implement asio_handler_invoke for your own handlers to specify a custom
* invocation strategy.
*
* This default implementation invokes the function object like so:
* @code function(); @endcode
* If necessary, the default implementation makes a copy of the function object
* so that the non-const operator() can be used.
*
* @par Example
* @code
* class my_handler;
*
* template
* void asio_handler_invoke(Function function, my_handler* context)
* {
* context->strand_.dispatch(function);
* }
* @endcode
*/
/*@{*/
#if defined(BOOST_ASIO_NO_DEPRECATED)
// Places in asio that would have previously called the invocation hook to
// execute a handler, now call it only to check whether the result type is this
// type. If the result is not this type, it indicates that the user code still
// has the old hooks in place, and if so we want to trigger a compile error.
enum asio_handler_invoke_is_no_longer_used {};
typedef asio_handler_invoke_is_no_longer_used
asio_handler_invoke_is_deprecated;
#else // defined(BOOST_ASIO_NO_DEPRECATED)
typedef void asio_handler_invoke_is_deprecated;
#endif // defined(BOOST_ASIO_NO_DEPRECATED)
/// Default handler invocation hook used for non-const function objects.
template
inline asio_handler_invoke_is_deprecated
asio_handler_invoke(Function& function, ...)
{
function();
#if defined(BOOST_ASIO_NO_DEPRECATED)
return asio_handler_invoke_is_no_longer_used();
#endif // defined(BOOST_ASIO_NO_DEPRECATED)
}
/// Default handler invocation hook used for const function objects.
template
inline asio_handler_invoke_is_deprecated
asio_handler_invoke(const Function& function, ...)
{
Function tmp(function);
tmp();
#if defined(BOOST_ASIO_NO_DEPRECATED)
return asio_handler_invoke_is_no_longer_used();
#endif // defined(BOOST_ASIO_NO_DEPRECATED)
}
/*@}*/
} // namespace asio
} // namespace boost
#include
#endif // BOOST_ASIO_HANDLER_INVOKE_HOOK_HPP