| // |
| // detail/winsock_init.hpp |
| // ~~~~~~~~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2016 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_DETAIL_WINSOCK_INIT_HPP |
| #define ASIO_DETAIL_WINSOCK_INIT_HPP |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
| # pragma once |
| #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
| |
| #include "asio/detail/config.hpp" |
| |
| #if defined(ASIO_WINDOWS) || defined(__CYGWIN__) |
| |
| #include "asio/detail/push_options.hpp" |
| |
| namespace asio { |
| namespace detail { |
| |
| class winsock_init_base |
| { |
| protected: |
| // Structure to track result of initialisation and number of uses. POD is used |
| // to ensure that the values are zero-initialised prior to any code being run. |
| struct data |
| { |
| long init_count_; |
| long result_; |
| }; |
| |
| ASIO_DECL static void startup(data& d, |
| unsigned char major, unsigned char minor); |
| |
| ASIO_DECL static void manual_startup(data& d); |
| |
| ASIO_DECL static void cleanup(data& d); |
| |
| ASIO_DECL static void manual_cleanup(data& d); |
| |
| ASIO_DECL static void throw_on_error(data& d); |
| }; |
| |
| template <int Major = 2, int Minor = 0> |
| class winsock_init : private winsock_init_base |
| { |
| public: |
| winsock_init(bool allow_throw = true) |
| { |
| startup(data_, Major, Minor); |
| if (allow_throw) |
| throw_on_error(data_); |
| } |
| |
| winsock_init(const winsock_init&) |
| { |
| startup(data_, Major, Minor); |
| throw_on_error(data_); |
| } |
| |
| ~winsock_init() |
| { |
| cleanup(data_); |
| } |
| |
| // This class may be used to indicate that user code will manage Winsock |
| // initialisation and cleanup. This may be required in the case of a DLL, for |
| // example, where it is not safe to initialise Winsock from global object |
| // constructors. |
| // |
| // To prevent asio from initialising Winsock, the object must be constructed |
| // before any Asio's own global objects. With MSVC, this may be accomplished |
| // by adding the following code to the DLL: |
| // |
| // #pragma warning(push) |
| // #pragma warning(disable:4073) |
| // #pragma init_seg(lib) |
| // asio::detail::winsock_init<>::manual manual_winsock_init; |
| // #pragma warning(pop) |
| class manual |
| { |
| public: |
| manual() |
| { |
| manual_startup(data_); |
| } |
| |
| manual(const manual&) |
| { |
| manual_startup(data_); |
| } |
| |
| ~manual() |
| { |
| manual_cleanup(data_); |
| } |
| }; |
| |
| private: |
| friend class manual; |
| static data data_; |
| }; |
| |
| template <int Major, int Minor> |
| winsock_init_base::data winsock_init<Major, Minor>::data_; |
| |
| // Static variable to ensure that winsock is initialised before main, and |
| // therefore before any other threads can get started. |
| static const winsock_init<>& winsock_init_instance = winsock_init<>(false); |
| |
| } // namespace detail |
| } // namespace asio |
| |
| #include "asio/detail/pop_options.hpp" |
| |
| #if defined(ASIO_HEADER_ONLY) |
| # include "asio/detail/impl/winsock_init.ipp" |
| #endif // defined(ASIO_HEADER_ONLY) |
| |
| #endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__) |
| |
| #endif // ASIO_DETAIL_WINSOCK_INIT_HPP |