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| <div class="titlepage"><div><div><h4 class="title"> |
| <a name="boost_asio.reference.windows__basic_stream_handle.async_read_some"></a><a class="link" href="async_read_some.html" title="windows::basic_stream_handle::async_read_some">windows::basic_stream_handle::async_read_some</a> |
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| <p> |
| <a class="indexterm" name="id1378844"></a> |
| Start an asynchronous read. |
| </p> |
| <pre class="programlisting"><span class="keyword">template</span><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="keyword">typename</span> <a class="link" href="../ReadHandler.html" title="Read handler requirements">ReadHandler</a><span class="special">></span> |
| <span class="keyword">void</span> <span class="identifier">async_read_some</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> |
| <span class="identifier">ReadHandler</span> <span class="identifier">handler</span><span class="special">);</span> |
| </pre> |
| <p> |
| This function is used to asynchronously read data from the stream handle. |
| The function call always returns immediately. |
| </p> |
| <a name="boost_asio.reference.windows__basic_stream_handle.async_read_some.parameters"></a><h6> |
| <a name="id1378978"></a> |
| <a class="link" href="async_read_some.html#boost_asio.reference.windows__basic_stream_handle.async_read_some.parameters">Parameters</a> |
| </h6> |
| <div class="variablelist"> |
| <p class="title"><b></b></p> |
| <dl> |
| <dt><span class="term">buffers</span></dt> |
| <dd><p> |
| One or more buffers into which the data will be read. Although the |
| buffers object may be copied as necessary, ownership of the underlying |
| memory blocks is retained by the caller, which must guarantee that |
| they remain valid until the handler is called. |
| </p></dd> |
| <dt><span class="term">handler</span></dt> |
| <dd> |
| <p> |
| The handler to be called when the read operation completes. Copies |
| will be made of the handler as required. The function signature of |
| the handler must be: |
| </p> |
| <pre class="programlisting"><span class="keyword">void</span> <span class="identifier">handler</span><span class="special">(</span> |
| <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&</span> <span class="identifier">error</span><span class="special">,</span> <span class="comment">// Result of operation. |
| </span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">bytes_transferred</span> <span class="comment">// Number of bytes read. |
| </span><span class="special">);</span> |
| </pre> |
| <p> |
| Regardless of whether the asynchronous operation completes immediately |
| or not, the handler will not be invoked from within this function. |
| Invocation of the handler will be performed in a manner equivalent |
| to using <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">post</span><span class="special">()</span></code>. |
| </p> |
| </dd> |
| </dl> |
| </div> |
| <a name="boost_asio.reference.windows__basic_stream_handle.async_read_some.remarks"></a><h6> |
| <a name="id1379189"></a> |
| <a class="link" href="async_read_some.html#boost_asio.reference.windows__basic_stream_handle.async_read_some.remarks">Remarks</a> |
| </h6> |
| <p> |
| The read operation may not read all of the requested number of bytes. Consider |
| using the <a class="link" href="../async_read.html" title="async_read"><code class="computeroutput"><span class="identifier">async_read</span></code></a> function if you need |
| to ensure that the requested amount of data is read before the asynchronous |
| operation completes. |
| </p> |
| <a name="boost_asio.reference.windows__basic_stream_handle.async_read_some.example"></a><h6> |
| <a name="id1379235"></a> |
| <a class="link" href="async_read_some.html#boost_asio.reference.windows__basic_stream_handle.async_read_some.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">handle</span><span class="special">.</span><span class="identifier">async_read_some</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> <span class="identifier">handler</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> |
| </div> |
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| <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>) |
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