doc/html/boost_asio/reference/read/overload1.html

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  26 <div class="titlepage"><div><div><h4 class="title">
  27 <a name="boost_asio.reference.read.overload1"></a><a class="link" href="overload1.html" title="read (1 of 8 overloads)">read (1 of 8 overloads)</a>
  28 </h4></div></div></div>
  29 <p>
  30           Attempt to read a certain amount of data from a stream before returning.
  31         </p>
  32 <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
  33     <span class="keyword">typename</span> <a class="link" href="../SyncReadStream.html" title="Buffer-oriented synchronous read stream requirements">SyncReadStream</a><span class="special">,</span>
  34     <span class="keyword">typename</span> <a class="link" href="../MutableBufferSequence.html" title="Mutable buffer sequence requirements">MutableBufferSequence</a><span class="special">&gt;</span>
  35 <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">read</span><span class="special">(</span>
  36     <span class="identifier">SyncReadStream</span> <span class="special">&amp;</span> <span class="identifier">s</span><span class="special">,</span>
  37     <span class="keyword">const</span> <span class="identifier">MutableBufferSequence</span> <span class="special">&amp;</span> <span class="identifier">buffers</span><span class="special">);</span>
  38 </pre>
  39 <p>
  40           This function is used to read a certain number of bytes of data from a
  41           stream. The call will block until one of the following conditions is true:
  42         </p>
  43 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
  44 <li class="listitem">
  45               The supplied buffers are full. That is, the bytes transferred is equal
  46               to the sum of the buffer sizes.
  47             </li>
  48 <li class="listitem">
  49               An error occurred.
  50             </li>
  51 </ul></div>
  52 <p>
  53           This operation is implemented in terms of zero or more calls to the stream's
  54           read_some function.
  55         </p>
  56 <h6>
  57 <a name="boost_asio.reference.read.overload1.h0"></a>
  58           <span class="phrase"><a name="boost_asio.reference.read.overload1.parameters"></a></span><a class="link" href="overload1.html#boost_asio.reference.read.overload1.parameters">Parameters</a>
  59         </h6>
  60 <div class="variablelist">
  61 <p class="title"><b></b></p>
  62 <dl class="variablelist">
  63 <dt><span class="term">s</span></dt>
  64 <dd><p>
  65                 The stream from which the data is to be read. The type must support
  66                 the SyncReadStream concept.
  67               </p></dd>
  68 <dt><span class="term">buffers</span></dt>
  69 <dd><p>
  70                 One or more buffers into which the data will be read. The sum of
  71                 the buffer sizes indicates the maximum number of bytes to read from
  72                 the stream.
  73               </p></dd>
  74 </dl>
  75 </div>
  76 <h6>
  77 <a name="boost_asio.reference.read.overload1.h1"></a>
  78           <span class="phrase"><a name="boost_asio.reference.read.overload1.return_value"></a></span><a class="link" href="overload1.html#boost_asio.reference.read.overload1.return_value">Return
  79           Value</a>
  80         </h6>
  81 <p>
  82           The number of bytes transferred.
  83         </p>
  84 <h6>
  85 <a name="boost_asio.reference.read.overload1.h2"></a>
  86           <span class="phrase"><a name="boost_asio.reference.read.overload1.exceptions"></a></span><a class="link" href="overload1.html#boost_asio.reference.read.overload1.exceptions">Exceptions</a>
  87         </h6>
  88 <div class="variablelist">
  89 <p class="title"><b></b></p>
  90 <dl class="variablelist">
  91 <dt><span class="term">boost::system::system_error</span></dt>
  92 <dd><p>
  93                 Thrown on failure.
  94               </p></dd>
  95 </dl>
  96 </div>
  97 <h6>
  98 <a name="boost_asio.reference.read.overload1.h3"></a>
  99           <span class="phrase"><a name="boost_asio.reference.read.overload1.example"></a></span><a class="link" href="overload1.html#boost_asio.reference.read.overload1.example">Example</a>
 100         </h6>
 101 <p>
 102           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:
 103         </p>
 104 <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>
 105 </pre>
 106 <p>
 107           See the <a class="link" href="../buffer.html" title="buffer"><code class="computeroutput"><span class="identifier">buffer</span></code></a>
 108           documentation for information on reading into multiple buffers in one go,
 109           and how to use it with arrays, boost::array or std::vector.
 110         </p>
 111 <h6>
 112 <a name="boost_asio.reference.read.overload1.h4"></a>
 113           <span class="phrase"><a name="boost_asio.reference.read.overload1.remarks"></a></span><a class="link" href="overload1.html#boost_asio.reference.read.overload1.remarks">Remarks</a>
 114         </h6>
 115 <p>
 116           This overload is equivalent to calling:
 117         </p>
 118 <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>
 119     <span class="identifier">s</span><span class="special">,</span> <span class="identifier">buffers</span><span class="special">,</span>
 120     <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>
 121 </pre>
 122 </div>
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 125 <td align="right"><div class="copyright-footer">Copyright &#169; 2003-2014 Christopher M. Kohlhoff<p>
 126         Distributed under the Boost Software License, Version 1.0. (See accompanying
 127         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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