1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>file_mode</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="../../index.html" title="Chapter 1. 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If the file does not exist prior to the function call, it 103 is created with an initial size of zero bytes. Otherwise if the 104 file already exists, the size is truncated to zero bytes. 105 </p> 106 </td> 107</tr> 108<tr> 109<td> 110 <p> 111 <code class="computeroutput"><span class="identifier">write_new</span></code> 112 </p> 113 </td> 114<td> 115 <p> 116 Random reading and writing to a new file only. 117 </p> 118 <p> 119 This mode permits random-access reading and writing for the specified 120 file. The file will be created with an initial size of zero bytes. 121 If the file already exists prior to the function call, an error 122 is returned and no file is opened. 123 </p> 124 </td> 125</tr> 126<tr> 127<td> 128 <p> 129 <code class="computeroutput"><span class="identifier">write_existing</span></code> 130 </p> 131 </td> 132<td> 133 <p> 134 Random write-only access to existing file. 135 </p> 136 <p> 137 If the file does not exist, an error is generated. 138 </p> 139 </td> 140</tr> 141<tr> 142<td> 143 <p> 144 <code class="computeroutput"><span class="identifier">append</span></code> 145 </p> 146 </td> 147<td> 148 <p> 149 Appending to a new or truncated file. 150 </p> 151 <p> 152 The current file position shall be set to the end of the file prior 153 to each write. 154 </p> 155 <p> 156 @li If the file does not exist, it is created. 157 </p> 158 <p> 159 @li If the file exists, it is truncated to zero size upon opening. 160 </p> 161 </td> 162</tr> 163<tr> 164<td> 165 <p> 166 <code class="computeroutput"><span class="identifier">append_existing</span></code> 167 </p> 168 </td> 169<td> 170 <p> 171 Appending to an existing file. 172 </p> 173 <p> 174 The current file position shall be set to the end of the file prior 175 to each write. 176 </p> 177 <p> 178 If the file does not exist, an error is generated. 179 </p> 180 </td> 181</tr> 182</tbody> 183</table></div> 184<h5> 185<a name="beast.ref.boost__beast__file_mode.h2"></a> 186 <span class="phrase"><a name="beast.ref.boost__beast__file_mode.description"></a></span><a class="link" href="boost__beast__file_mode.html#beast.ref.boost__beast__file_mode.description">Description</a> 187 </h5> 188<p> 189 These modes are used when opening files using instances of the <span class="emphasis"><em>File</em></span> 190 concept. 191 </p> 192<h5> 193<a name="beast.ref.boost__beast__file_mode.h3"></a> 194 <span class="phrase"><a name="beast.ref.boost__beast__file_mode.see_also"></a></span><a class="link" href="boost__beast__file_mode.html#beast.ref.boost__beast__file_mode.see_also">See 195 Also</a> 196 </h5> 197<p> 198 <a class="link" href="boost__beast__file_stdio.html" title="file_stdio"><code class="computeroutput"><span class="identifier">file_stdio</span></code></a> 199 </p> 200</div> 201<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 202<td align="left"></td> 203<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Vinnie 204 Falco<p> 205 Distributed under the Boost Software License, Version 1.0. (See accompanying 206 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>) 207 </p> 208</div></td> 209</tr></table> 210<hr> 211<div class="spirit-nav"> 212<a accesskey="p" href="boost__beast__condition.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../ref.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="boost__beast__role_type.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 213</div> 214</body> 215</html> 216
