113 lines
5.2 KiB
HTML
113 lines
5.2 KiB
HTML
<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
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<title>Socket Iostreams</title>
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<link rel="stylesheet" href="../../../boostbook.css" type="text/css">
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<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
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<link rel="home" href="../../../index.html" title="Asio">
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<link rel="up" href="../networking.html" title="Networking">
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<link rel="prev" href="other_protocols.html" title="Support for Other Protocols">
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<link rel="next" href="bsd_sockets.html" title="The BSD Socket API and Asio">
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</head>
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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
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<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="asio C++ library" width="250" height="60" src="../../../asio.png"></td></tr></table>
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<hr>
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<div class="spirit-nav">
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<a accesskey="p" href="other_protocols.html"><img src="../../../prev.png" alt="Prev"></a><a accesskey="u" href="../networking.html"><img src="../../../up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../home.png" alt="Home"></a><a accesskey="n" href="bsd_sockets.html"><img src="../../../next.png" alt="Next"></a>
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</div>
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<div class="section">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="asio.overview.networking.iostreams"></a><a class="link" href="iostreams.html" title="Socket Iostreams">Socket Iostreams</a>
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</h4></div></div></div>
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<p>
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Asio includes classes that implement iostreams on top of sockets. These
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hide away the complexities associated with endpoint resolution, protocol
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independence, etc. To create a connection one might simply write:
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</p>
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<pre class="programlisting">ip::tcp::iostream stream("www.boost.org", "http");
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if (!stream)
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{
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// Can't connect.
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}
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</pre>
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<p>
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The iostream class can also be used in conjunction with an acceptor to
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create simple servers. For example:
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</p>
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<pre class="programlisting">io_context ioc;
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ip::tcp::endpoint endpoint(tcp::v4(), 80);
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ip::tcp::acceptor acceptor(ios, endpoint);
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for (;;)
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{
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ip::tcp::iostream stream;
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acceptor.accept(stream.socket());
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...
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}
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</pre>
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<p>
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Timeouts may be set by calling <code class="computeroutput">expires_at()</code> or <code class="computeroutput">expires_from_now()</code>
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to establish a deadline. Any socket operations that occur past the deadline
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will put the iostream into a "bad" state.
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</p>
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<p>
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For example, a simple client program like this:
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</p>
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<pre class="programlisting">ip::tcp::iostream stream;
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stream.expires_from_now(boost::posix_time::seconds(60));
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stream.connect("www.boost.org", "http");
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stream << "GET /LICENSE_1_0.txt HTTP/1.0\r\n";
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stream << "Host: www.boost.org\r\n";
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stream << "Accept: */*\r\n";
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stream << "Connection: close\r\n\r\n";
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stream.flush();
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std::cout << stream.rdbuf();
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</pre>
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<p>
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will fail if all the socket operations combined take longer than 60 seconds.
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</p>
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<p>
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If an error does occur, the iostream's <code class="computeroutput">error()</code> member function
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may be used to retrieve the error code from the most recent system call:
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</p>
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<pre class="programlisting">if (!stream)
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{
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std::cout << "Error: " << stream.error().message() << "\n";
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}
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</pre>
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<h6>
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<a name="asio.overview.networking.iostreams.h0"></a>
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<span><a name="asio.overview.networking.iostreams.see_also"></a></span><a class="link" href="iostreams.html#asio.overview.networking.iostreams.see_also">See
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Also</a>
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</h6>
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<p>
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<a class="link" href="../../reference/ip__tcp/iostream.html" title="ip::tcp::iostream">ip::tcp::iostream</a>,
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<a class="link" href="../../reference/basic_socket_iostream.html" title="basic_socket_iostream">basic_socket_iostream</a>,
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<a class="link" href="../../examples/cpp03_examples.html#asio.examples.cpp03_examples.iostreams">iostreams examples</a>.
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</p>
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<h6>
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<a name="asio.overview.networking.iostreams.h1"></a>
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<span><a name="asio.overview.networking.iostreams.notes"></a></span><a class="link" href="iostreams.html#asio.overview.networking.iostreams.notes">Notes</a>
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</h6>
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<p>
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These iostream templates only support <code class="computeroutput">char</code>, not <code class="computeroutput">wchar_t</code>,
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and do not perform any code conversion.
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</p>
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</div>
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<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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<td align="left"></td>
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<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M.
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Kohlhoff<p>
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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 <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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</p>
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</div></td>
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</tr></table>
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<hr>
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<div class="spirit-nav">
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<a accesskey="p" href="other_protocols.html"><img src="../../../prev.png" alt="Prev"></a><a accesskey="u" href="../networking.html"><img src="../../../up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../home.png" alt="Home"></a><a accesskey="n" href="bsd_sockets.html"><img src="../../../next.png" alt="Next"></a>
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</div>
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