1 | // |
2 | // detail/winsock_init.hpp |
3 | // ~~~~~~~~~~~~~~~~~~~~~~~ |
4 | // |
5 | // Copyright (c) 2003-2015 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 |
131 | |