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<div class="titlepage"><div><div><h4 class="title">
<a name="boost_asio.overview.posix.stream_descriptor"></a><a class="link" href="stream_descriptor.html" title="Stream-Oriented File Descriptors">Stream-Oriented
File Descriptors</a>
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<p>
Boost.Asio includes classes added to permit synchronous and asynchronous
read and write operations to be performed on POSIX file descriptors, such
as pipes, standard input and output, and various devices (but <span class="emphasis"><em>not</em></span>
regular files).
</p>
<p>
For example, to perform read and write operations on standard input and
output, the following objects may be created:
</p>
<pre class="programlisting"><span class="identifier">posix</span><span class="special">::</span><span class="identifier">stream_descriptor</span> <span class="identifier">in</span><span class="special">(</span><span class="identifier">my_io_service</span><span class="special">,</span> <span class="special">::</span><span class="identifier">dup</span><span class="special">(</span><span class="identifier">STDIN_FILENO</span><span class="special">));</span>
<span class="identifier">posix</span><span class="special">::</span><span class="identifier">stream_descriptor</span> <span class="identifier">out</span><span class="special">(</span><span class="identifier">my_io_service</span><span class="special">,</span> <span class="special">::</span><span class="identifier">dup</span><span class="special">(</span><span class="identifier">STDOUT_FILENO</span><span class="special">));</span>
</pre>
<p>
These are then used as synchronous or asynchronous read and write streams.
This means the objects can be used with any of the <a class="link" href="../../reference/read.html" title="read">read()</a>,
<a class="link" href="../../reference/async_read.html" title="async_read">async_read()</a>, <a class="link" href="../../reference/write.html" title="write">write()</a>, <a class="link" href="../../reference/async_write.html" title="async_write">async_write()</a>,
<a class="link" href="../../reference/read_until.html" title="read_until">read_until()</a> or
<a class="link" href="../../reference/async_read_until.html" title="async_read_until">async_read_until()</a>
free functions.
</p>
<h6>
<a name="boost_asio.overview.posix.stream_descriptor.h0"></a>
<span class="phrase"><a name="boost_asio.overview.posix.stream_descriptor.see_also"></a></span><a class="link" href="stream_descriptor.html#boost_asio.overview.posix.stream_descriptor.see_also">See Also</a>
</h6>
<p>
<a class="link" href="../../reference/posix__stream_descriptor.html" title="posix::stream_descriptor">posix::stream_descriptor</a>,
<a class="link" href="../../reference/posix__basic_stream_descriptor.html" title="posix::basic_stream_descriptor">posix::basic_stream_descriptor</a>,
<a class="link" href="../../reference/posix__stream_descriptor_service.html" title="posix::stream_descriptor_service">posix::stream_descriptor_service</a>,
<a class="link" href="../../examples/cpp03_examples.html#boost_asio.examples.cpp03_examples.chat">Chat example (C++03)</a>,
<a class="link" href="../../examples/cpp11_examples.html#boost_asio.examples.cpp11_examples.chat">Chat example (C++11)</a>.
</p>
<h6>
<a name="boost_asio.overview.posix.stream_descriptor.h1"></a>
<span class="phrase"><a name="boost_asio.overview.posix.stream_descriptor.notes"></a></span><a class="link" href="stream_descriptor.html#boost_asio.overview.posix.stream_descriptor.notes">Notes</a>
</h6>
<p>
POSIX stream descriptors are only available at compile time if supported
by the target operating system. A program may test for the macro <code class="computeroutput"><span class="identifier">BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR</span></code>
to determine whether they are supported.
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