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<title>Socket Iostreams</title>
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<div class="section">
<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">ip::tcp::iostream stream("www.boost.org", "http");
if (!stream)
{
// Can't connect.
}
</pre>
<p>
The iostream class can also be used in conjunction with an acceptor to
create simple servers. For example:
</p>
<pre class="programlisting">io_context ioc;
ip::tcp::endpoint endpoint(tcp::v4(), 80);
ip::tcp::acceptor acceptor(ios, endpoint);
for (;;)
{
ip::tcp::iostream stream;
acceptor.accept(stream.socket());
...
}
</pre>
<p>
Timeouts may be set by calling <code class="computeroutput">expires_at()</code> or <code class="computeroutput">expires_from_now()</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">ip::tcp::iostream stream;
stream.expires_from_now(boost::posix_time::seconds(60));
stream.connect("www.boost.org", "http");
stream << "GET /LICENSE_1_0.txt HTTP/1.0\r\n";
stream << "Host: www.boost.org\r\n";
stream << "Accept: */*\r\n";
stream << "Connection: close\r\n\r\n";
stream.flush();
std::cout << stream.rdbuf();
</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">error()</code> member function
may be used to retrieve the error code from the most recent system call:
</p>
<pre class="programlisting">if (!stream)
{
std::cout << "Error: " << stream.error().message() << "\n";
}
</pre>
<h6>
<a name="boost_asio.overview.networking.iostreams.h0"></a>
<span class="phrase"><a name="boost_asio.overview.networking.iostreams.see_also"></a></span><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/cpp03_examples.html#boost_asio.examples.cpp03_examples.iostreams">iostreams
examples</a>.
</p>
<h6>
<a name="boost_asio.overview.networking.iostreams.h1"></a>
<span class="phrase"><a name="boost_asio.overview.networking.iostreams.notes"></a></span><a class="link" href="iostreams.html#boost_asio.overview.networking.iostreams.notes">Notes</a>
</h6>
<p>
These iostream templates only support <code class="computeroutput">char</code>, not <code class="computeroutput">wchar_t</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 © 2003-2017 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>
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