1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>write (3 of 16 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="../write.html" title="write"> 9<link rel="prev" href="overload2.html" title="write (2 of 16 overloads)"> 10<link rel="next" href="overload4.html" title="write (4 of 16 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="overload2.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../write.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="overload4.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.write.overload3"></a><a class="link" href="overload3.html" title="write (3 of 16 overloads)">write (3 of 16 28 overloads)</a> 29</h4></div></div></div> 30<p> 31 Write a certain amount of data to a stream before returning. 32 </p> 33<pre class="programlisting">template< 34 typename <a class="link" href="../SyncWriteStream.html" title="Buffer-oriented synchronous write stream requirements">SyncWriteStream</a>, 35 typename <a class="link" href="../ConstBufferSequence.html" title="Constant buffer sequence requirements">ConstBufferSequence</a>, 36 typename <a class="link" href="../CompletionCondition.html" title="Completion condition requirements">CompletionCondition</a>> 37std::size_t write( 38 SyncWriteStream & s, 39 const ConstBufferSequence & buffers, 40 CompletionCondition completion_condition, 41 typename enable_if< is_const_buffer_sequence< ConstBufferSequence >::value >::type * = 0); 42</pre> 43<p> 44 This function is used to write a certain number of bytes of data to a stream. 45 The call will block until one of the following conditions is true: 46 </p> 47<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 48<li class="listitem"> 49 All of the data in the supplied buffers has been written. That is, 50 the bytes transferred is equal to the sum of the buffer sizes. 51 </li> 52<li class="listitem"> 53 The completion_condition function object returns 0. 54 </li> 55</ul></div> 56<p> 57 This operation is implemented in terms of zero or more calls to the stream's 58 write_some function. 59 </p> 60<h6> 61<a name="boost_asio.reference.write.overload3.h0"></a> 62 <span class="phrase"><a name="boost_asio.reference.write.overload3.parameters"></a></span><a class="link" href="overload3.html#boost_asio.reference.write.overload3.parameters">Parameters</a> 63 </h6> 64<div class="variablelist"> 65<p class="title"><b></b></p> 66<dl class="variablelist"> 67<dt><span class="term">s</span></dt> 68<dd><p> 69 The stream to which the data is to be written. The type must support 70 the SyncWriteStream concept. 71 </p></dd> 72<dt><span class="term">buffers</span></dt> 73<dd><p> 74 One or more buffers containing the data to be written. The sum of 75 the buffer sizes indicates the maximum number of bytes to write to 76 the stream. 77 </p></dd> 78<dt><span class="term">completion_condition</span></dt> 79<dd> 80<p> 81 The function object to be called to determine whether the write operation 82 is complete. The signature of the function object must be: 83</p> 84<pre class="programlisting">std::size_t completion_condition( 85 // Result of latest write_some operation. 86 const boost::system::error_code& error, 87 88 // Number of bytes transferred so far. 89 std::size_t bytes_transferred 90); 91</pre> 92<p> 93 A return value of 0 indicates that the write operation is complete. 94 A non-zero return value indicates the maximum number of bytes to 95 be written on the next call to the stream's write_some function. 96 </p> 97</dd> 98</dl> 99</div> 100<h6> 101<a name="boost_asio.reference.write.overload3.h1"></a> 102 <span class="phrase"><a name="boost_asio.reference.write.overload3.return_value"></a></span><a class="link" href="overload3.html#boost_asio.reference.write.overload3.return_value">Return 103 Value</a> 104 </h6> 105<p> 106 The number of bytes transferred. 107 </p> 108<h6> 109<a name="boost_asio.reference.write.overload3.h2"></a> 110 <span class="phrase"><a name="boost_asio.reference.write.overload3.exceptions"></a></span><a class="link" href="overload3.html#boost_asio.reference.write.overload3.exceptions">Exceptions</a> 111 </h6> 112<div class="variablelist"> 113<p class="title"><b></b></p> 114<dl class="variablelist"> 115<dt><span class="term">boost::system::system_error</span></dt> 116<dd><p> 117 Thrown on failure. 118 </p></dd> 119</dl> 120</div> 121<h6> 122<a name="boost_asio.reference.write.overload3.h3"></a> 123 <span class="phrase"><a name="boost_asio.reference.write.overload3.example"></a></span><a class="link" href="overload3.html#boost_asio.reference.write.overload3.example">Example</a> 124 </h6> 125<p> 126 To write a single data buffer use the <a class="link" href="../buffer.html" title="buffer"><code class="computeroutput">buffer</code></a> 127 function as follows: 128 </p> 129<pre class="programlisting">boost::asio::write(s, boost::asio::buffer(data, size), 130 boost::asio::transfer_at_least(32)); 131</pre> 132<p> 133 See the <a class="link" href="../buffer.html" title="buffer"><code class="computeroutput">buffer</code></a> 134 documentation for information on writing multiple buffers in one go, and 135 how to use it with arrays, boost::array or std::vector. 136 </p> 137</div> 138<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 139<td align="left"></td> 140<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M. 141 Kohlhoff<p> 142 Distributed under the Boost Software License, Version 1.0. (See accompanying 143 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>) 144 </p> 145</div></td> 146</tr></table> 147<hr> 148<div class="spirit-nav"> 149<a accesskey="p" href="overload2.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../write.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="overload4.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 150</div> 151</body> 152</html> 153
