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| <div class="titlepage"><div><div><h4 class="title"> |
| <a name="boost_asio.overview.networking.iostreams"></a><a class="link" href="iostreams.html" title="Socket Iostreams">Socket Iostreams</a> |
| </h4></div></div></div> |
| <p> |
| Boost.Asio includes classes that implement iostreams on top of sockets. |
| These hide away the complexities associated with endpoint resolution, protocol |
| independence, etc. To create a connection one might simply write: |
| </p> |
| <pre class="programlisting"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">iostream</span> <span class="identifier">stream</span><span class="special">(</span><span class="string">"www.boost.org"</span><span class="special">,</span> <span class="string">"http"</span><span class="special">);</span> |
| <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">stream</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="comment">// Can't connect.</span> |
| <span class="special">}</span> |
| </pre> |
| <p> |
| The iostream class can also be used in conjunction with an acceptor to |
| create simple servers. For example: |
| </p> |
| <pre class="programlisting"><span class="identifier">io_service</span> <span class="identifier">ios</span><span class="special">;</span> |
| |
| <span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">endpoint</span> <span class="identifier">endpoint</span><span class="special">(</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">v4</span><span class="special">(),</span> <span class="number">80</span><span class="special">);</span> |
| <span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">acceptor</span> <span class="identifier">acceptor</span><span class="special">(</span><span class="identifier">ios</span><span class="special">,</span> <span class="identifier">endpoint</span><span class="special">);</span> |
| |
| <span class="keyword">for</span> <span class="special">(;;)</span> |
| <span class="special">{</span> |
| <span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">iostream</span> <span class="identifier">stream</span><span class="special">;</span> |
| <span class="identifier">acceptor</span><span class="special">.</span><span class="identifier">accept</span><span class="special">(*</span><span class="identifier">stream</span><span class="special">.</span><span class="identifier">rdbuf</span><span class="special">());</span> |
| <span class="special">...</span> |
| <span class="special">}</span> |
| </pre> |
| <p> |
| Timeouts may be set by calling <code class="computeroutput"><span class="identifier">expires_at</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">expires_from_now</span><span class="special">()</span></code> to establish a deadline. Any socket operations |
| that occur past the deadline will put the iostream into a "bad" |
| state. |
| </p> |
| <p> |
| For example, a simple client program like this: |
| </p> |
| <pre class="programlisting"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">iostream</span> <span class="identifier">stream</span><span class="special">;</span> |
| <span class="identifier">stream</span><span class="special">.</span><span class="identifier">expires_from_now</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">posix_time</span><span class="special">::</span><span class="identifier">seconds</span><span class="special">(</span><span class="number">60</span><span class="special">));</span> |
| <span class="identifier">stream</span><span class="special">.</span><span class="identifier">connect</span><span class="special">(</span><span class="string">"www.boost.org"</span><span class="special">,</span> <span class="string">"http"</span><span class="special">);</span> |
| <span class="identifier">stream</span> <span class="special"><<</span> <span class="string">"GET /LICENSE_1_0.txt HTTP/1.0\r\n"</span><span class="special">;</span> |
| <span class="identifier">stream</span> <span class="special"><<</span> <span class="string">"Host: www.boost.org\r\n"</span><span class="special">;</span> |
| <span class="identifier">stream</span> <span class="special"><<</span> <span class="string">"Accept: */*\r\n"</span><span class="special">;</span> |
| <span class="identifier">stream</span> <span class="special"><<</span> <span class="string">"Connection: close\r\n\r\n"</span><span class="special">;</span> |
| <span class="identifier">stream</span><span class="special">.</span><span class="identifier">flush</span><span class="special">();</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">stream</span><span class="special">.</span><span class="identifier">rdbuf</span><span class="special">();</span> |
| </pre> |
| <p> |
| will fail if all the socket operations combined take longer than 60 seconds. |
| </p> |
| <p> |
| If an error does occur, the iostream's <code class="computeroutput"><span class="identifier">error</span><span class="special">()</span></code> member function may be used to retrieve |
| the error code from the most recent system call: |
| </p> |
| <pre class="programlisting"><span class="keyword">if</span> <span class="special">(!</span><span class="identifier">stream</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Error: "</span> <span class="special"><<</span> <span class="identifier">stream</span><span class="special">.</span><span class="identifier">error</span><span class="special">().</span><span class="identifier">message</span><span class="special">()</span> <span class="special"><<</span> <span class="string">"\n"</span><span class="special">;</span> |
| <span class="special">}</span> |
| </pre> |
| <a name="boost_asio.overview.networking.iostreams.see_also"></a><h6> |
| <a name="boost_asio.overview.networking.iostreams.see_also-heading"></a> |
| <a class="link" href="iostreams.html#boost_asio.overview.networking.iostreams.see_also">See Also</a> |
| </h6> |
| <p> |
| <a class="link" href="../../reference/ip__tcp/iostream.html" title="ip::tcp::iostream">ip::tcp::iostream</a>, |
| <a class="link" href="../../reference/basic_socket_iostream.html" title="basic_socket_iostream">basic_socket_iostream</a>, |
| <a class="link" href="../../examples.html#boost_asio.examples.iostreams">iostreams examples</a>. |
| </p> |
| <a name="boost_asio.overview.networking.iostreams.notes"></a><h6> |
| <a name="boost_asio.overview.networking.iostreams.notes-heading"></a> |
| <a class="link" href="iostreams.html#boost_asio.overview.networking.iostreams.notes">Notes</a> |
| </h6> |
| <p> |
| These iostream templates only support <code class="computeroutput"><span class="keyword">char</span></code>, |
| not <code class="computeroutput"><span class="keyword">wchar_t</span></code>, and do not perform |
| any code conversion. |
| </p> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2003-2011 Christopher |
| M. Kohlhoff<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) |
| </p> |
| </div></td> |
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