1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>read_until (8 of 24 overloads)</title> 5<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../boost_asio.html" title="Boost.Asio"> 8<link rel="up" href="../read_until.html" title="read_until"> 9<link rel="prev" href="overload7.html" title="read_until (7 of 24 overloads)"> 10<link rel="next" href="overload9.html" title="read_until (9 of 24 overloads)"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="overload7.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../read_until.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="overload9.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="boost_asio.reference.read_until.overload8"></a><a class="link" href="overload8.html" title="read_until (8 of 24 overloads)">read_until 28 (8 of 24 overloads)</a> 29</h4></div></div></div> 30<p> 31 Read data into a dynamic buffer sequence until a function object indicates 32 a match. 33 </p> 34<pre class="programlisting">template< 35 typename <a class="link" href="../SyncReadStream.html" title="Buffer-oriented synchronous read stream requirements">SyncReadStream</a>, 36 typename <a class="link" href="../DynamicBuffer_v1.html" title="Dynamic buffer requirements (version 1)">DynamicBuffer_v1</a>, 37 typename MatchCondition> 38std::size_t read_until( 39 SyncReadStream & s, 40 DynamicBuffer_v1 && buffers, 41 MatchCondition match_condition, 42 boost::system::error_code & ec, 43 typename enable_if< is_match_condition< MatchCondition >::value &&is_dynamic_buffer_v1< typename decay< DynamicBuffer_v1 >::type >::value &&!is_dynamic_buffer_v2< typename decay< DynamicBuffer_v1 >::type >::value >::type * = 0); 44</pre> 45<p> 46 This function is used to read data into the specified dynamic buffer sequence 47 until a user-defined match condition function object, when applied to the 48 data contained in the dynamic buffer sequence, indicates a successful match. 49 The call will block until one of the following conditions is true: 50 </p> 51<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 52<li class="listitem"> 53 The match condition function object returns a std::pair where the second 54 element evaluates to true. 55 </li> 56<li class="listitem"> 57 An error occurred. 58 </li> 59</ul></div> 60<p> 61 This operation is implemented in terms of zero or more calls to the stream's 62 read_some function. If the match condition function object already indicates 63 a match, the function returns immediately. 64 </p> 65<h6> 66<a name="boost_asio.reference.read_until.overload8.h0"></a> 67 <span class="phrase"><a name="boost_asio.reference.read_until.overload8.parameters"></a></span><a class="link" href="overload8.html#boost_asio.reference.read_until.overload8.parameters">Parameters</a> 68 </h6> 69<div class="variablelist"> 70<p class="title"><b></b></p> 71<dl class="variablelist"> 72<dt><span class="term">s</span></dt> 73<dd><p> 74 The stream from which the data is to be read. The type must support 75 the SyncReadStream concept. 76 </p></dd> 77<dt><span class="term">buffers</span></dt> 78<dd><p> 79 A dynamic buffer sequence into which the data will be read. 80 </p></dd> 81<dt><span class="term">match_condition</span></dt> 82<dd> 83<p> 84 The function object to be called to determine whether a match exists. 85 The signature of the function object must be: 86</p> 87<pre class="programlisting">pair<iterator, bool> match_condition(iterator begin, iterator end); 88</pre> 89<p> 90 where <code class="computeroutput">iterator</code> represents the type: 91</p> 92<pre class="programlisting">buffers_iterator<DynamicBuffer_v1::const_buffers_type> 93</pre> 94<p> 95 The iterator parameters <code class="computeroutput">begin</code> and <code class="computeroutput">end</code> define 96 the range of bytes to be scanned to determine whether there is a 97 match. The <code class="computeroutput">first</code> member of the return value is an iterator 98 marking one-past-the-end of the bytes that have been consumed by 99 the match function. This iterator is used to calculate the <code class="computeroutput">begin</code> 100 parameter for any subsequent invocation of the match condition. The 101 <code class="computeroutput">second</code> member of the return value is true if a match 102 has been found, false otherwise. 103 </p> 104</dd> 105<dt><span class="term">ec</span></dt> 106<dd><p> 107 Set to indicate what error occurred, if any. 108 </p></dd> 109</dl> 110</div> 111<h6> 112<a name="boost_asio.reference.read_until.overload8.h1"></a> 113 <span class="phrase"><a name="boost_asio.reference.read_until.overload8.return_value"></a></span><a class="link" href="overload8.html#boost_asio.reference.read_until.overload8.return_value">Return 114 Value</a> 115 </h6> 116<p> 117 The number of bytes in the dynamic buffer sequence's get area that have 118 been fully consumed by the match function. Returns 0 if an error occurred. 119 </p> 120<h6> 121<a name="boost_asio.reference.read_until.overload8.h2"></a> 122 <span class="phrase"><a name="boost_asio.reference.read_until.overload8.remarks"></a></span><a class="link" href="overload8.html#boost_asio.reference.read_until.overload8.remarks">Remarks</a> 123 </h6> 124<p> 125 After a successful read_until operation, the dynamic buffer sequence may 126 contain additional data beyond that which matched the function object. 127 An application will typically leave that data in the dynamic buffer sequence 128 for a subsequent read_until operation to examine. 129 </p> 130<p> 131 The default implementation of the <code class="computeroutput">is_match_condition</code> type 132 trait evaluates to true for function pointers and function objects with 133 a <code class="computeroutput">result_type</code> typedef. It must be specialised for other user-defined 134 function objects. 135 </p> 136</div> 137<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 138<td align="left"></td> 139<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M. 140 Kohlhoff<p> 141 Distributed under the Boost Software License, Version 1.0. (See accompanying 142 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>) 143 </p> 144</div></td> 145</tr></table> 146<hr> 147<div class="spirit-nav"> 148<a accesskey="p" href="overload7.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../read_until.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="overload9.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 149</div> 150</body> 151</html> 152
