ceph/src/boost/boost/asio/detail/winsock_init.hpp

   1 //
   2 // detail/winsock_init.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #ifndef BOOST_ASIO_DETAIL_WINSOCK_INIT_HPP
  12 #define BOOST_ASIO_DETAIL_WINSOCK_INIT_HPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  17
  18 #include <boost/asio/detail/config.hpp>
  19
  20 #if defined(BOOST_ASIO_WINDOWS) || defined(__CYGWIN__)
  21
  22 #include <boost/asio/detail/push_options.hpp>
  23
  24 namespace boost {
  25 namespace asio {
  26 namespace detail {
  27
  28 class winsock_init_base
  29 {
  30 protected:
  31   // Structure to track result of initialisation and number of uses. POD is used
  32   // to ensure that the values are zero-initialised prior to any code being run.
  33   struct data
  34   {
  35     long init_count_;
  36     long result_;
  37   };
  38
  39   BOOST_ASIO_DECL static void startup(data& d,
  40       unsigned char major, unsigned char minor);
  41
  42   BOOST_ASIO_DECL static void manual_startup(data& d);
  43
  44   BOOST_ASIO_DECL static void cleanup(data& d);
  45
  46   BOOST_ASIO_DECL static void manual_cleanup(data& d);
  47
  48   BOOST_ASIO_DECL static void throw_on_error(data& d);
  49 };
  50
  51 template <int Major = 2, int Minor = 0>
  52 class winsock_init : private winsock_init_base
  53 {
  54 public:
  55   winsock_init(bool allow_throw = true)
  56   {
  57     startup(data_, Major, Minor);
  58     if (allow_throw)
  59       throw_on_error(data_);
  60   }
  61
  62   winsock_init(const winsock_init&)
  63   {
  64     startup(data_, Major, Minor);
  65     throw_on_error(data_);
  66   }
  67
  68   ~winsock_init()
  69   {
  70     cleanup(data_);
  71   }
  72
  73   // This class may be used to indicate that user code will manage Winsock
  74   // initialisation and cleanup. This may be required in the case of a DLL, for
  75   // example, where it is not safe to initialise Winsock from global object
  76   // constructors.
  77   //
  78   // To prevent asio from initialising Winsock, the object must be constructed
  79   // before any Asio's own global objects. With MSVC, this may be accomplished
  80   // by adding the following code to the DLL:
  81   //
  82   //   #pragma warning(push)
  83   //   #pragma warning(disable:4073)
  84   //   #pragma init_seg(lib)
  85   //   boost::asio::detail::winsock_init<>::manual manual_winsock_init;
  86   //   #pragma warning(pop)
  87   class manual
  88   {
  89   public:
  90     manual()
  91     {
  92       manual_startup(data_);
  93     }
  94
  95     manual(const manual&)
  96     {
  97       manual_startup(data_);
  98     }
  99
 100     ~manual()
 101     {
 102       manual_cleanup(data_);
 103     }
 104   };
 105
 106 private:
 107   friend class manual;
 108   static data data_;
 109 };
 110
 111 template <int Major, int Minor>
 112 winsock_init_base::data winsock_init<Major, Minor>::data_;
 113
 114 // Static variable to ensure that winsock is initialised before main, and
 115 // therefore before any other threads can get started.
 116 static const winsock_init<>& winsock_init_instance = winsock_init<>(false);
 117
 118 } // namespace detail
 119 } // namespace asio
 120 } // namespace boost
 121
 122 #include <boost/asio/detail/pop_options.hpp>
 123
 124 #if defined(BOOST_ASIO_HEADER_ONLY)
 125 # include <boost/asio/detail/impl/winsock_init.ipp>
 126 #endif // defined(BOOST_ASIO_HEADER_ONLY)
 127
 128 #endif // defined(BOOST_ASIO_WINDOWS) || defined(__CYGWIN__)
 129
 130 #endif // BOOST_ASIO_DETAIL_WINSOCK_INIT_HPP