<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Buffer-oriented synchronous random-access read device requirements</title>
<link rel="stylesheet" href="../../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.73.2">
<link rel="start" href="../../index.html" title="Asio">
<link rel="up" href="../reference.html" title="Reference">
<link rel="prev" href="StreamSocketService.html" title="Stream socket service requirements">
<link rel="next" href="SyncRandomAccessWriteDevice.html" title="Buffer-oriented synchronous random-access write device requirements">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="asio C++ library" width="250" height="60" src="../../asio.png"></td></tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="StreamSocketService.html"><img src="../../prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../home.png" alt="Home"></a><a accesskey="n" href="SyncRandomAccessWriteDevice.html"><img src="../../next.png" alt="Next"></a>
</div>
<div class="section" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="asio.reference.SyncRandomAccessReadDevice"></a><a class="link" href="SyncRandomAccessReadDevice.html" title="Buffer-oriented synchronous random-access read device requirements"> Buffer-oriented
synchronous random-access read device requirements</a>
</h3></div></div></div>
<p>
In the table below, <code class="computeroutput"><span class="identifier">a</span></code> denotes
a synchronous random-access read device object, <code class="computeroutput"><span class="identifier">o</span></code>
denotes an offset of type <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">uint64_t</span></code>,
<code class="computeroutput"><span class="identifier">mb</span></code> denotes an object satisfying
<a class="link" href="MutableBufferSequence.html" title="Mutable buffer sequence requirements">mutable buffer sequence</a>
requirements, and <code class="computeroutput"><span class="identifier">ec</span></code> denotes
an object of type <code class="computeroutput"><span class="identifier">error_code</span></code>.
</p>
<div class="table">
<a name="id571709"></a><p class="title"><b>Table 31. Buffer-oriented synchronous random-access read device
requirements</b></p>
<div class="table-contents"><table class="table" summary="Buffer-oriented synchronous random-access read device
requirements">
<colgroup>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>
<p>
operation
</p>
</th>
<th>
<p>
type
</p>
</th>
<th>
<p>
semantics, pre/post-conditions
</p>
</th>
</tr></thead>
<tbody>
<tr>
<td>
<p>
<code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">read_some_at</span><span class="special">(</span><span class="identifier">o</span><span class="special">,</span> <span class="identifier">mb</span><span class="special">);</span></code>
</p>
</td>
<td>
<p>
<code class="computeroutput"><span class="identifier">size_t</span></code>
</p>
</td>
<td>
<p>
Equivalent to:
</p>
<pre class="programlisting"><span class="identifier">error_code</span> <span class="identifier">ec</span><span class="special">;</span>
<span class="identifier">size_t</span> <span class="identifier">s</span> <span class="special">=</span> <span class="identifier">a</span><span class="special">.</span><span class="identifier">read_some_at</span><span class="special">(</span><span class="identifier">o</span><span class="special">,</span> <span class="identifier">mb</span><span class="special">,</span> <span class="identifier">ec</span><span class="special">);</span>
<span class="keyword">if</span> <span class="special">(</span><span class="identifier">ec</span><span class="special">)</span> <span class="keyword">throw</span> <span class="identifier">system_error</span><span class="special">(</span><span class="identifier">ec</span><span class="special">);</span>
<span class="keyword">return</span> <span class="identifier">s</span><span class="special">;</span>
</pre>
<p>
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">read_some_at</span><span class="special">(</span><span class="identifier">o</span><span class="special">,</span> <span class="identifier">mb</span><span class="special">,</span> <span class="identifier">ec</span><span class="special">);</span></code>
</p>
</td>
<td>
<p>
<code class="computeroutput"><span class="identifier">size_t</span></code>
</p>
</td>
<td>
<p>
Reads one or more bytes of data from the device <code class="computeroutput"><span class="identifier">a</span></code>
at offset <code class="computeroutput"><span class="identifier">o</span></code>.<br>
<br> The mutable buffer sequence <code class="computeroutput"><span class="identifier">mb</span></code>
specifies memory where the data should be placed. The <code class="computeroutput"><span class="identifier">read_some_at</span></code> operation shall always
fill a buffer in the sequence completely before proceeding to the next.<br>
<br> If successful, returns the number of bytes read and sets <code class="computeroutput"><span class="identifier">ec</span></code> such that <code class="computeroutput"><span class="special">!</span><span class="identifier">ec</span></code> is true. If an error occurred,
returns <code class="computeroutput"><span class="number">0</span></code> and sets <code class="computeroutput"><span class="identifier">ec</span></code> such that <code class="computeroutput"><span class="special">!!</span><span class="identifier">ec</span></code> is true.<br> <br> If the total
size of all buffers in the sequence <code class="computeroutput"><span class="identifier">mb</span></code>
is <code class="computeroutput"><span class="number">0</span></code>, the function shall
return <code class="computeroutput"><span class="number">0</span></code> immediately.
</p>
</td>
</tr>
</tbody>
</table></div>
</div>
<br class="table-break">
</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="StreamSocketService.html"><img src="../../prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../home.png" alt="Home"></a><a accesskey="n" href="SyncRandomAccessWriteDevice.html"><img src="../../next.png" alt="Next"></a>
</div>
</body>
</html>
distrib
>
Mageia
>
1
>
i586
>
media
>
core-release
>
by-pkgid
>
2deed065cd3adb9905decb703c6b0100
>
files
>
296
