overload7.html
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<div class="titlepage"><div><div><h4 class="title">
<a name="asio.reference.read.overload7"></a><a class="link" href="overload7.html" title="read (7 of 16 overloads)">read (7 of 16 overloads)</a>
</h4></div></div></div>
<p>
Attempt to read a certain amount of data from a stream before returning.
</p>
<pre class="programlisting">template<
typename <a class="link" href="../SyncReadStream.html" title="Buffer-oriented synchronous read stream requirements">SyncReadStream</a>,
typename <a class="link" href="../DynamicBuffer_v1.html" title="Dynamic buffer requirements (version 1)">DynamicBuffer_v1</a>,
typename <a class="link" href="../CompletionCondition.html" title="Completion condition requirements">CompletionCondition</a>>
std::size_t read(
SyncReadStream & s,
DynamicBuffer_v1 && buffers,
CompletionCondition completion_condition,
typename enable_if< is_dynamic_buffer_v1< typename decay< DynamicBuffer_v1 >::type >::value &&!is_dynamic_buffer_v2< typename decay< DynamicBuffer_v1 >::type >::value >::type * = 0);
</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 specified dynamic buffer sequence is full (that is, it has reached
maximum size).
</li>
<li class="listitem">
The completion_condition function object returns 0.
</li>
</ul></div>
<p>
This operation is implemented in terms of zero or more calls to the stream's
read_some function.
</p>
<h6>
<a name="asio.reference.read.overload7.h0"></a>
<span><a name="asio.reference.read.overload7.parameters"></a></span><a class="link" href="overload7.html#asio.reference.read.overload7.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>
The dynamic buffer sequence into which the data will be read.
</p></dd>
<dt><span class="term">completion_condition</span></dt>
<dd>
<p>
The function object to be called to determine whether the read operation
is complete. The signature of the function object must be:
</p>
<pre class="programlisting">std::size_t completion_condition(
// Result of latest read_some operation.
const asio::error_code& error,
// Number of bytes transferred so far.
std::size_t bytes_transferred
);
</pre>
<p>
A return value of 0 indicates that the read operation is complete.
A non-zero return value indicates the maximum number of bytes to
be read on the next call to the stream's read_some function.
</p>
</dd>
</dl>
</div>
<h6>
<a name="asio.reference.read.overload7.h1"></a>
<span><a name="asio.reference.read.overload7.return_value"></a></span><a class="link" href="overload7.html#asio.reference.read.overload7.return_value">Return
Value</a>
</h6>
<p>
The number of bytes transferred.
</p>
<h6>
<a name="asio.reference.read.overload7.h2"></a>
<span><a name="asio.reference.read.overload7.exceptions"></a></span><a class="link" href="overload7.html#asio.reference.read.overload7.exceptions">Exceptions</a>
</h6>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">asio::system_error</span></dt>
<dd><p>
Thrown on failure.
</p></dd>
</dl>
</div>
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<td align="right"><div class="copyright-footer">Copyright © 2003-2020 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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