<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>read (1 of 6 overloads)</title> <link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> <meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> <link rel="home" href="../../../boost_asio.html" title="Boost.Asio"> <link rel="up" href="../read.html" title="read"> <link rel="prev" href="../read.html" title="read"> <link rel="next" href="overload2.html" title="read (2 of 6 overloads)"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" width="100%"><tr> <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td> <td align="center"><a href="../../../../../index.html">Home</a></td> <td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td> <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> <td align="center"><a href="../../../../../more/index.htm">More</a></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="../read.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../read.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../boost_asio.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="overload2.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> </div> <div class="section"> <div class="titlepage"><div><div><h4 class="title"> <a name="boost_asio.reference.read.overload1"></a><a class="link" href="overload1.html" title="read (1 of 6 overloads)"> read (1 of 6 overloads)</a> </h4></div></div></div> <p> Attempt to read a certain amount of data from a stream before returning. </p> <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <a class="link" href="../SyncReadStream.html" title="Buffer-oriented synchronous read stream requirements">SyncReadStream</a><span class="special">,</span> <span class="keyword">typename</span> <a class="link" href="../MutableBufferSequence.html" title="Mutable buffer sequence requirements">MutableBufferSequence</a><span class="special">></span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">read</span><span class="special">(</span> <span class="identifier">SyncReadStream</span> <span class="special">&</span> <span class="identifier">s</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">MutableBufferSequence</span> <span class="special">&</span> <span class="identifier">buffers</span><span class="special">);</span> </pre> <p> This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true: </p> <div class="itemizedlist"><ul class="itemizedlist" type="disc"> <li class="listitem"> The supplied buffers are full. That is, the bytes transferred is equal to the sum of the buffer sizes. </li> <li class="listitem"> An error occurred. </li> </ul></div> <p> This operation is implemented in terms of zero or more calls to the stream's read_some function. </p> <a name="boost_asio.reference.read.overload1.parameters"></a><h6> <a name="id1286420"></a> <a class="link" href="overload1.html#boost_asio.reference.read.overload1.parameters">Parameters</a> </h6> <div class="variablelist"> <p class="title"><b></b></p> <dl> <dt><span class="term">s</span></dt> <dd><p> The stream from which the data is to be read. The type must support the SyncReadStream concept. </p></dd> <dt><span class="term">buffers</span></dt> <dd><p> One or more buffers into which the data will be read. The sum of the buffer sizes indicates the maximum number of bytes to read from the stream. </p></dd> </dl> </div> <a name="boost_asio.reference.read.overload1.return_value"></a><h6> <a name="id1286478"></a> <a class="link" href="overload1.html#boost_asio.reference.read.overload1.return_value">Return Value</a> </h6> <p> The number of bytes transferred. </p> <a name="boost_asio.reference.read.overload1.exceptions"></a><h6> <a name="id1286504"></a> <a class="link" href="overload1.html#boost_asio.reference.read.overload1.exceptions">Exceptions</a> </h6> <div class="variablelist"> <p class="title"><b></b></p> <dl> <dt><span class="term">boost::system::system_error</span></dt> <dd><p> Thrown on failure. </p></dd> </dl> </div> <a name="boost_asio.reference.read.overload1.example"></a><h6> <a name="id1286545"></a> <a class="link" href="overload1.html#boost_asio.reference.read.overload1.example">Example</a> </h6> <p> To read into a single data buffer use the <a class="link" href="../buffer.html" title="buffer"><code class="computeroutput"><span class="identifier">buffer</span></code></a> function as follows: </p> <pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">read</span><span class="special">(</span><span class="identifier">s</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">buffer</span><span class="special">(</span><span class="identifier">data</span><span class="special">,</span> <span class="identifier">size</span><span class="special">));</span> </pre> <p> See the <a class="link" href="../buffer.html" title="buffer"><code class="computeroutput"><span class="identifier">buffer</span></code></a> documentation for information on reading into multiple buffers in one go, and how to use it with arrays, boost::array or std::vector. </p> <a name="boost_asio.reference.read.overload1.remarks"></a><h6> <a name="id1286696"></a> <a class="link" href="overload1.html#boost_asio.reference.read.overload1.remarks">Remarks</a> </h6> <p> This overload is equivalent to calling: </p> <pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">read</span><span class="special">(</span> <span class="identifier">s</span><span class="special">,</span> <span class="identifier">buffers</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">transfer_all</span><span class="special">());</span> </pre> </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 - 2010 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> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="../read.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../read.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../boost_asio.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="overload2.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html>