1<?xml version="1.0" encoding="UTF-8" standalone="no"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml"> 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 6 <title>Chapter��5.�� The DB_ENV Handle</title> 7 <link rel="stylesheet" href="apiReference.css" type="text/css" /> 8 <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> 9 <link rel="start" href="index.html" title="Berkeley DB C API Reference" /> 10 <link rel="up" href="index.html" title="Berkeley DB C API Reference" /> 11 <link rel="prev" href="DB_MULTIPLE_RECNO_RESERVE_NEXT.html" title="DB_MULTIPLE_RECNO_RESERVE_NEXT" /> 12 <link rel="next" href="dbgetenv.html" title="DB->get_env()" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">Chapter��5.�� 19 The DB_ENV Handle 20 </th> 21 </tr> 22 <tr> 23 <td width="20%" align="left"><a accesskey="p" href="DB_MULTIPLE_RECNO_RESERVE_NEXT.html">Prev</a>��</td> 24 <th width="60%" align="center">��</th> 25 <td width="20%" align="right">��<a accesskey="n" href="dbgetenv.html">Next</a></td> 26 </tr> 27 </table> 28 <hr /> 29 </div> 30 <div class="chapter" lang="en" xml:lang="en"> 31 <div class="titlepage"> 32 <div> 33 <div> 34 <h2 class="title"><a id="env"></a>Chapter��5.�� 35 The DB_ENV Handle 36 </h2> 37 </div> 38 </div> 39 </div> 40 <p> 41 The <code class="classname">DB_ENV</code> object is the handle for a Berkeley DB environment 42 ��� a collection including support for some or all of caching, locking, logging and 43 transaction subsystems, as well as databases and log files. Methods of the 44 <code class="classname">DB_ENV</code> handle are used to configure the environment as well as 45 to operate on subsystems and databases in the environment. 46 </p> 47 <p> 48 <code class="classname">DB_ENV</code> handles 49 <span> 50 are created using the <a class="xref" href="envcreate.html" title="db_env_create">db_env_create</a> 51 method, and 52 </span> 53 are opened using the <a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a> 54 method. 55 </p> 56 <p> 57 When you are done using your environment, close it using the 58 <a class="xref" href="envclose.html" title="DB_ENV->close()">DB_ENV->close()</a> method. Before closing your 59 environment, make sure all open database handles are closed first. See the 60 <a class="xref" href="dbclose.html" title="DB->close()">DB->close()</a> method for more information. 61 </p> 62 <div class="sect1" lang="en" xml:lang="en"> 63 <div class="titlepage"> 64 <div> 65 <div> 66 <h2 class="title" style="clear: both"><a id="envlist"></a>Database Environments and Related Methods</h2> 67 </div> 68 </div> 69 </div> 70 <div class="navtable"> 71 <table border="1" width="80%"> 72 <thead> 73 <tr> 74 <th>Database Environment Operations</th> 75 <th>Description</th> 76 </tr> 77 </thead> 78 <tbody> 79 <tr> 80 <td> 81 <a class="xref" href="dbgetenv.html" title="DB->get_env()">DB->get_env()</a> 82 </td> 83 <td>Return the DB's underlying DB_ENV handle </td> 84 </tr> 85 <tr> 86 <td> 87 <a class="xref" href="envclose.html" title="DB_ENV->close()">DB_ENV->close()</a> 88 </td> 89 <td>Close an environment</td> 90 </tr> 91 <tr> 92 <td> 93 <a class="xref" href="envcreate.html" title="db_env_create">db_env_create</a> 94 </td> 95 <td>Create an environment handle</td> 96 </tr> 97 <tr> 98 <td> 99 <a class="xref" href="envdbremove.html" title="DB_ENV->dbremove()">DB_ENV->dbremove()</a> 100 </td> 101 <td>Remove a database</td> 102 </tr> 103 <tr> 104 <td> 105 <a class="xref" href="envdbrename.html" title="DB_ENV->dbrename()">DB_ENV->dbrename()</a> 106 </td> 107 <td>Rename a database</td> 108 </tr> 109 <tr> 110 <td> 111 <a class="xref" href="enverr.html" title="DB_ENV->err()">DB_ENV->err()</a> 112 </td> 113 <td>Error message</td> 114 </tr> 115 <tr> 116 <td> 117 <a class="xref" href="envfailchk.html" title="DB_ENV->failchk()">DB_ENV->failchk()</a> 118 </td> 119 <td>Check for thread failure</td> 120 </tr> 121 <tr> 122 <td> 123 <a class="xref" href="envfileid_reset.html" title="DB_ENV->fileid_reset()">DB_ENV->fileid_reset()</a> 124 </td> 125 <td>Reset database file IDs</td> 126 </tr> 127 <tr> 128 <td> 129 <a class="xref" href="envget_home.html" title="DB_ENV->get_home()">DB_ENV->get_home()</a> 130 </td> 131 <td>Return environment's home directory</td> 132 </tr> 133 <tr> 134 <td> 135 <a class="xref" href="envget_open_flags.html" title="DB_ENV->get_open_flags()">DB_ENV->get_open_flags()</a> 136 </td> 137 <td>Return flags with which the environment was opened</td> 138 </tr> 139 <tr> 140 <td> 141 <a class="xref" href="envlsn_reset.html" title="DB_ENV->lsn_reset()">DB_ENV->lsn_reset()</a> 142 </td> 143 <td>Reset database file LSNs</td> 144 </tr> 145 <tr> 146 <td> 147 <a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a> 148 </td> 149 <td>Open an environment</td> 150 </tr> 151 <tr> 152 <td> 153 <a class="xref" href="envremove.html" title="DB_ENV->remove()">DB_ENV->remove()</a> 154 </td> 155 <td>Remove an environment</td> 156 </tr> 157 <tr> 158 <td> 159 <a class="xref" href="envstat.html" title="DB_ENV->stat_print()">DB_ENV->stat_print()</a> 160 </td> 161 <td>Environment statistics</td> 162 </tr> 163 <tr> 164 <td> 165 <a class="xref" href="envstrerror.html" title="db_strerror">db_strerror</a> 166 </td> 167 <td>Error strings</td> 168 </tr> 169 <tr> 170 <td> 171 <a class="xref" href="envversion.html" title="db_version">db_version</a> 172 </td> 173 <td>Return version information</td> 174 </tr> 175 <tr> 176 <td colspan="2"> 177 <span class="bold"> 178 <strong>Environment Configuration</strong> 179 </span> 180 </td> 181 </tr> 182 <tr> 183 <td> 184 <a class="xref" href="envadd_data_dir.html" title="DB_ENV->add_data_dir()">DB_ENV->add_data_dir()</a> 185 </td> 186 <td>add an environment data directory</td> 187 </tr> 188 <tr> 189 <td> 190 <a class="xref" href="envset_alloc.html" title="DB_ENV->set_alloc()">DB_ENV->set_alloc()</a> 191 </td> 192 <td>Set local space allocation functions</td> 193 </tr> 194 <tr> 195 <td> 196 <a class="xref" href="envset_app_dispatch.html" title="DB_ENV->set_app_dispatch()">DB_ENV->set_app_dispatch()</a> 197 </td> 198 <td>Configure application recovery callback</td> 199 </tr> 200 <tr> 201 <td><a class="xref" href="envset_data_dir.html" title="DB_ENV->set_data_dir()">DB_ENV->set_data_dir()</a>, <a class="xref" href="envget_data_dirs.html" title="DB_ENV->get_data_dirs()">DB_ENV->get_data_dirs()</a></td> 202 <td>Set/get the environment data directory</td> 203 </tr> 204 <tr> 205 <td><a class="xref" href="envset_create_dir.html" title="DB_ENV->set_create_dir()">DB_ENV->set_create_dir()</a>, <a class="xref" href="envget_create_dir.html" title="DB_ENV->get_create_dir()">DB_ENV->get_create_dir()</a></td> 206 <td>add an environment data directory</td> 207 </tr> 208 <tr> 209 <td><a class="xref" href="envset_encrypt.html" title="DB_ENV->set_encrypt()">DB_ENV->set_encrypt()</a>, <a class="xref" href="envget_encrypt_flags.html" title="DB_ENV->get_encrypt_flags()">DB_ENV->get_encrypt_flags()</a></td> 210 <td>Set/get the environment cryptographic key</td> 211 </tr> 212 <tr> 213 <td> 214 <a class="xref" href="envevent_notify.html" title="DB_ENV->set_event_notify()">DB_ENV->set_event_notify()</a> 215 </td> 216 <td>Set event notification callback</td> 217 </tr> 218 <tr> 219 <td> 220 <a class="xref" href="envset_errcall.html" title="DB_ENV->set_errcall()">DB_ENV->set_errcall()</a> 221 </td> 222 <td>Set error message callbacks</td> 223 </tr> 224 <tr> 225 <td><a class="xref" href="envset_errfile.html" title="DB_ENV->set_errfile()">DB_ENV->set_errfile()</a>, <a class="xref" href="envget_errfile.html" title="DB_ENV->get_errfile()">DB_ENV->get_errfile()</a></td> 226 <td>Set/get error message FILE</td> 227 </tr> 228 <tr> 229 <td><a class="xref" href="envset_errpfx.html" title="DB_ENV->set_errpfx()">DB_ENV->set_errpfx()</a>, <a class="xref" href="envget_errpfx.html" title="DB_ENV->get_errpfx()">DB_ENV->get_errpfx()</a></td> 230 <td>Set/get error message prefix</td> 231 </tr> 232 <tr> 233 <td> 234 <a class="xref" href="envset_feedback.html" title="DB_ENV->set_feedback()">DB_ENV->set_feedback()</a> 235 </td> 236 <td>Set feedback callback</td> 237 </tr> 238 <tr> 239 <td><a class="xref" href="envset_flags.html" title="DB_ENV->set_flags()">DB_ENV->set_flags()</a>, <a class="xref" href="envget_flags.html" title="DB_ENV->get_flags()">DB_ENV->get_flags()</a></td> 240 <td>Environment configuration</td> 241 </tr> 242 <tr> 243 <td><a class="xref" href="envset_intermediate_dir_mode.html" title="DB_ENV->set_intermediate_dir_mode()">DB_ENV->set_intermediate_dir_mode()</a>, <a class="xref" href="envget_intermediate_dir_mode.html" title="DB_ENV->get_intermediate_dir_mode()">DB_ENV->get_intermediate_dir_mode()</a></td> 244 <td>Set/get intermediate directory creation mode</td> 245 </tr> 246 <tr> 247 <td> 248 <a class="xref" href="envset_isalive.html" title="DB_ENV->set_isalive()">DB_ENV->set_isalive()</a> 249 </td> 250 <td>Set thread is-alive callback</td> 251 </tr> 252 <tr> 253 <td> 254 <a class="xref" href="envset_msgcall.html" title="DB_ENV->set_msgcall()">DB_ENV->set_msgcall()</a> 255 </td> 256 <td>Set informational message callback</td> 257 </tr> 258 <tr> 259 <td><a class="xref" href="envset_msgfile.html" title="DB_ENV->set_msgfile()">DB_ENV->set_msgfile()</a>, <a class="xref" href="envget_msgfile.html" title="DB_ENV->get_msgfile()">DB_ENV->get_msgfile()</a></td> 260 <td>Set/get informational message FILE</td> 261 </tr> 262 <tr> 263 <td><a class="xref" href="envset_shm_key.html" title="DB_ENV->set_shm_key()">DB_ENV->set_shm_key()</a>, <a class="xref" href="envget_shm_key.html" title="DB_ENV->get_shm_key()">DB_ENV->get_shm_key()</a></td> 264 <td>Set/get system memory shared segment ID</td> 265 </tr> 266 <tr> 267 <td><a class="xref" href="envset_thread_count.html" title="DB_ENV->set_thread_count()">DB_ENV->set_thread_count()</a>, <a class="xref" href="envget_thread_count.html" title="DB_ENV->get_thread_count()">DB_ENV->get_thread_count()</a></td> 268 <td>Set/get approximate thread count</td> 269 </tr> 270 <tr> 271 <td> 272 <a class="xref" href="envset_thread_id.html" title="DB_ENV->set_thread_id()">DB_ENV->set_thread_id()</a> 273 </td> 274 <td>Set thread of control ID function</td> 275 </tr> 276 <tr> 277 <td> 278 <a class="xref" href="envset_thread_id_string.html" title="DB_ENV->set_thread_id_string()">DB_ENV->set_thread_id_string()</a> 279 </td> 280 <td>Set thread of control ID format function</td> 281 </tr> 282 <tr> 283 <td><a class="xref" href="envset_timeout.html" title="DB_ENV->set_timeout()">DB_ENV->set_timeout()</a>, <a class="xref" href="envget_timeout.html" title="DB_ENV->get_timeout()">DB_ENV->get_timeout()</a></td> 284 <td>Set/get lock and transaction timeout</td> 285 </tr> 286 <tr> 287 <td><a class="xref" href="envset_tmp_dir.html" title="DB_ENV->set_tmp_dir()">DB_ENV->set_tmp_dir()</a>, <a class="xref" href="envget_tmp_dir.html" title="DB_ENV->get_tmp_dir()">DB_ENV->get_tmp_dir()</a></td> 288 <td>Set/get the environment temporary file directory</td> 289 </tr> 290 <tr> 291 <td><a class="xref" href="envset_verbose.html" title="DB_ENV->set_verbose()">DB_ENV->set_verbose()</a>, <a class="xref" href="envget_verbose.html" title="DB_ENV->get_verbose()">DB_ENV->get_verbose()</a></td> 292 <td>Set/get verbose messages</td> 293 </tr> 294 <tr> 295 <td><a class="xref" href="envset_cachesize.html" title="DB_ENV->set_cachesize()">DB_ENV->set_cachesize()</a>, <a class="xref" href="envget_cachesize.html" title="DB_ENV->get_cachesize()">DB_ENV->get_cachesize()</a></td> 296 <td>Set/get the environment cache size</td> 297 </tr> 298 </tbody> 299 </table> 300 </div> 301 </div> 302 </div> 303 <div class="navfooter"> 304 <hr /> 305 <table width="100%" summary="Navigation footer"> 306 <tr> 307 <td width="40%" align="left"><a accesskey="p" href="DB_MULTIPLE_RECNO_RESERVE_NEXT.html">Prev</a>��</td> 308 <td width="20%" align="center">��</td> 309 <td width="40%" align="right">��<a accesskey="n" href="dbgetenv.html">Next</a></td> 310 </tr> 311 <tr> 312 <td width="40%" align="left" valign="top">DB_MULTIPLE_RECNO_RESERVE_NEXT��</td> 313 <td width="20%" align="center"> 314 <a accesskey="h" href="index.html">Home</a> 315 </td> 316 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