Chris@16: //
Chris@16: // detail/winsock_init.hpp
Chris@16: // ~~~~~~~~~~~~~~~~~~~~~~~
Chris@16: //
Chris@101: // Copyright (c) 2003-2015 Christopher M. Kohlhoff (chris at kohlhoff dot com)
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: 
Chris@16: #ifndef BOOST_ASIO_DETAIL_WINSOCK_INIT_HPP
Chris@16: #define BOOST_ASIO_DETAIL_WINSOCK_INIT_HPP
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1200)
Chris@16: # pragma once
Chris@16: #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
Chris@16: 
Chris@16: #include <boost/asio/detail/config.hpp>
Chris@16: 
Chris@16: #if defined(BOOST_ASIO_WINDOWS) || defined(__CYGWIN__)
Chris@16: 
Chris@16: #include <boost/asio/detail/push_options.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace asio {
Chris@16: namespace detail {
Chris@16: 
Chris@16: class winsock_init_base
Chris@16: {
Chris@16: protected:
Chris@16:   // Structure to track result of initialisation and number of uses. POD is used
Chris@16:   // to ensure that the values are zero-initialised prior to any code being run.
Chris@16:   struct data
Chris@16:   {
Chris@16:     long init_count_;
Chris@16:     long result_;
Chris@16:   };
Chris@16: 
Chris@16:   BOOST_ASIO_DECL static void startup(data& d,
Chris@16:       unsigned char major, unsigned char minor);
Chris@16: 
Chris@16:   BOOST_ASIO_DECL static void manual_startup(data& d);
Chris@16: 
Chris@16:   BOOST_ASIO_DECL static void cleanup(data& d);
Chris@16: 
Chris@16:   BOOST_ASIO_DECL static void manual_cleanup(data& d);
Chris@16: 
Chris@16:   BOOST_ASIO_DECL static void throw_on_error(data& d);
Chris@16: };
Chris@16: 
Chris@16: template <int Major = 2, int Minor = 0>
Chris@16: class winsock_init : private winsock_init_base
Chris@16: {
Chris@16: public:
Chris@16:   winsock_init(bool allow_throw = true)
Chris@16:   {
Chris@16:     startup(data_, Major, Minor);
Chris@16:     if (allow_throw)
Chris@16:       throw_on_error(data_);
Chris@16:   }
Chris@16: 
Chris@16:   winsock_init(const winsock_init&)
Chris@16:   {
Chris@16:     startup(data_, Major, Minor);
Chris@16:     throw_on_error(data_);
Chris@16:   }
Chris@16: 
Chris@16:   ~winsock_init()
Chris@16:   {
Chris@16:     cleanup(data_);
Chris@16:   }
Chris@16: 
Chris@16:   // This class may be used to indicate that user code will manage Winsock
Chris@16:   // initialisation and cleanup. This may be required in the case of a DLL, for
Chris@16:   // example, where it is not safe to initialise Winsock from global object
Chris@16:   // constructors.
Chris@16:   //
Chris@16:   // To prevent asio from initialising Winsock, the object must be constructed
Chris@16:   // before any Asio's own global objects. With MSVC, this may be accomplished
Chris@16:   // by adding the following code to the DLL:
Chris@16:   //
Chris@16:   //   #pragma warning(push)
Chris@16:   //   #pragma warning(disable:4073)
Chris@16:   //   #pragma init_seg(lib)
Chris@16:   //   boost::asio::detail::winsock_init<>::manual manual_winsock_init;
Chris@16:   //   #pragma warning(pop)
Chris@16:   class manual
Chris@16:   {
Chris@16:   public:
Chris@16:     manual()
Chris@16:     {
Chris@16:       manual_startup(data_);
Chris@16:     }
Chris@16: 
Chris@16:     manual(const manual&)
Chris@16:     {
Chris@16:       manual_startup(data_);
Chris@16:     }
Chris@16: 
Chris@16:     ~manual()
Chris@16:     {
Chris@16:       manual_cleanup(data_);
Chris@16:     }
Chris@16:   };
Chris@16: 
Chris@16: private:
Chris@16:   friend class manual;
Chris@16:   static data data_;
Chris@16: };
Chris@16: 
Chris@16: template <int Major, int Minor>
Chris@16: winsock_init_base::data winsock_init<Major, Minor>::data_;
Chris@16: 
Chris@16: // Static variable to ensure that winsock is initialised before main, and
Chris@16: // therefore before any other threads can get started.
Chris@16: static const winsock_init<>& winsock_init_instance = winsock_init<>(false);
Chris@16: 
Chris@16: } // namespace detail
Chris@16: } // namespace asio
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/asio/detail/pop_options.hpp>
Chris@16: 
Chris@16: #if defined(BOOST_ASIO_HEADER_ONLY)
Chris@16: # include <boost/asio/detail/impl/winsock_init.ipp>
Chris@16: #endif // defined(BOOST_ASIO_HEADER_ONLY)
Chris@16: 
Chris@16: #endif // defined(BOOST_ASIO_WINDOWS) || defined(__CYGWIN__)
Chris@16: 
Chris@16: #endif // BOOST_ASIO_DETAIL_WINSOCK_INIT_HPP