129 lines
3.0 KiB
C++
129 lines
3.0 KiB
C++
//
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// detail/winsock_init.hpp
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// ~~~~~~~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef ASIO_DETAIL_WINSOCK_INIT_HPP
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#define ASIO_DETAIL_WINSOCK_INIT_HPP
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#if defined(_MSC_VER) && (_MSC_VER >= 1200)
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# pragma once
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#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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#include "asio/detail/config.hpp"
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#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
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#include "asio/detail/push_options.hpp"
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namespace asio {
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namespace detail {
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class winsock_init_base
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{
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protected:
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// Structure to track result of initialisation and number of uses. POD is used
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// to ensure that the values are zero-initialised prior to any code being run.
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struct data
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{
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long init_count_;
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long result_;
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};
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ASIO_DECL static void startup(data& d,
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unsigned char major, unsigned char minor);
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ASIO_DECL static void manual_startup(data& d);
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ASIO_DECL static void cleanup(data& d);
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ASIO_DECL static void manual_cleanup(data& d);
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ASIO_DECL static void throw_on_error(data& d);
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};
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template <int Major = 2, int Minor = 0>
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class winsock_init : private winsock_init_base
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{
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public:
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winsock_init(bool allow_throw = true)
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{
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startup(data_, Major, Minor);
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if (allow_throw)
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throw_on_error(data_);
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}
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winsock_init(const winsock_init&)
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{
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startup(data_, Major, Minor);
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throw_on_error(data_);
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}
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~winsock_init()
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{
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cleanup(data_);
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}
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// This class may be used to indicate that user code will manage Winsock
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// initialisation and cleanup. This may be required in the case of a DLL, for
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// example, where it is not safe to initialise Winsock from global object
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// constructors.
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//
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// To prevent asio from initialising Winsock, the object must be constructed
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// before any Asio's own global objects. With MSVC, this may be accomplished
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// by adding the following code to the DLL:
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//
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// #pragma warning(push)
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// #pragma warning(disable:4073)
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// #pragma init_seg(lib)
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// asio::detail::winsock_init<>::manual manual_winsock_init;
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// #pragma warning(pop)
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class manual
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{
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public:
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manual()
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{
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manual_startup(data_);
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}
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manual(const manual&)
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{
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manual_startup(data_);
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}
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~manual()
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{
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manual_cleanup(data_);
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}
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};
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private:
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friend class manual;
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static data data_;
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};
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template <int Major, int Minor>
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winsock_init_base::data winsock_init<Major, Minor>::data_;
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// Static variable to ensure that winsock is initialised before main, and
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// therefore before any other threads can get started.
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static const winsock_init<>& winsock_init_instance = winsock_init<>(false);
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} // namespace detail
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} // namespace asio
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#include "asio/detail/pop_options.hpp"
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#if defined(ASIO_HEADER_ONLY)
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# include "asio/detail/impl/winsock_init.ipp"
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#endif // defined(ASIO_HEADER_ONLY)
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#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
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#endif // ASIO_DETAIL_WINSOCK_INIT_HPP
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