boost/asio/detail/winsock_init.hpp
//
// winsock_init.hpp
// ~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2008 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_DETAIL_WINSOCK_INIT_HPP
#define BOOST_ASIO_DETAIL_WINSOCK_INIT_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include <boost/asio/detail/push_options.hpp>
#include <boost/asio/detail/push_options.hpp>
#include <boost/config.hpp>
#include <boost/system/system_error.hpp>
#include <boost/asio/detail/pop_options.hpp>
#if defined(BOOST_WINDOWS) || defined(__CYGWIN__)
#include <boost/asio/detail/push_options.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/throw_exception.hpp>
#include <boost/asio/detail/pop_options.hpp>
#include <boost/asio/error.hpp>
#include <boost/asio/detail/noncopyable.hpp>
#include <boost/asio/detail/socket_types.hpp>
namespace boost {
namespace asio {
namespace detail {
template <int Major = 2, int Minor = 0>
class winsock_init
: private noncopyable
{
private:
// Structure to perform the actual initialisation.
struct do_init
{
do_init()
{
WSADATA wsa_data;
result_ = ::WSAStartup(MAKEWORD(Major, Minor), &wsa_data);
}
~do_init()
{
::WSACleanup();
}
int result() const
{
return result_;
}
// Helper function to manage a do_init singleton. The static instance of the
// winsock_init object ensures that this function is always called before
// main, and therefore before any other threads can get started. The do_init
// instance must be static in this function to ensure that it gets
// initialised before any other global objects try to use it.
static boost::shared_ptr<do_init> instance()
{
static boost::shared_ptr<do_init> init(new do_init);
return init;
}
private:
int result_;
};
public:
// Constructor.
winsock_init()
: ref_(do_init::instance())
{
// Check whether winsock was successfully initialised. This check is not
// performed for the global instance since there will be nobody around to
// catch the exception.
if (this != &instance_ && ref_->result() != 0)
{
boost::system::system_error e(
boost::system::error_code(ref_->result(),
boost::asio::error::get_system_category()),
"winsock");
boost::throw_exception(e);
}
}
// Destructor.
~winsock_init()
{
}
private:
// Instance to force initialisation of winsock at global scope.
static winsock_init instance_;
// Reference to singleton do_init object to ensure that winsock does not get
// cleaned up until the last user has finished with it.
boost::shared_ptr<do_init> ref_;
};
template <int Major, int Minor>
winsock_init<Major, Minor> winsock_init<Major, Minor>::instance_;
} // namespace detail
} // namespace asio
} // namespace boost
#endif // defined(BOOST_WINDOWS) || defined(__CYGWIN__)
#include <boost/asio/detail/pop_options.hpp>
#endif // BOOST_ASIO_DETAIL_WINSOCK_INIT_HPP