<!--$Id: env_close.so,v 10.38 2004/08/13 03:38:56 bostic Exp $--> <!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DbEnv::close</title> <meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> <meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> </head> <body bgcolor=white> <table width="100%"><tr valign=top> <td> <b>DbEnv::close</b> </td> <td align=right> <a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a> <a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td> </tr></table> <hr size=1 noshade> <tt> <b><pre> #include <db_cxx.h> <p> DbEnv::close(u_int32_t flags); </pre></b> <hr size=1 noshade> <b>Description: DbEnv::close</b> <p>The DbEnv::close method closes the Berkeley DB environment, freeing any allocated resources and closing any underlying subsystems.</p> <p>The <a href="../api_cxx/env_class.html">DbEnv</a> handle should not be closed while any other handle that refers to it is not yet closed; for example, database environment handles must not be closed while database handles remain open, or transactions in the environment have not yet been committed or aborted. Specifically, this includes <a href="../api_cxx/db_class.html">Db</a>, <a href="../api_cxx/dbc_class.html">Dbc</a>, <a href="../api_cxx/txn_class.html">DbTxn</a>, <a href="../api_cxx/logc_class.html">DbLogc</a> and <a href="../api_cxx/mempfile_class.html">DbMpoolFile</a> handles.</p> <p>Where the environment was initialized with the <a href="../api_cxx/env_open.html#DB_INIT_LOCK">DB_INIT_LOCK</a> flag, calling DbEnv::close does not release any locks still held by the closing process, providing functionality for long-lived locks. Processes that want to have all their locks released can do so by issuing the appropriate <a href="../api_cxx/lock_vec.html">DbEnv::lock_vec</a> call.</p> <p>Where the environment was initialized with the <a href="../api_cxx/env_open.html#DB_INIT_MPOOL">DB_INIT_MPOOL</a> flag, calling DbEnv::close implies calls to <a href="../api_cxx/memp_fclose.html">DbMpoolFile::close</a> for any remaining open files in the memory pool that were returned to this process by calls to <a href="../api_cxx/memp_fopen.html">DbMpoolFile::open</a>. It does not imply a call to <a href="../api_cxx/memp_fsync.html">DbMpoolFile::sync</a> for those files.</p> <p>Where the environment was initialized with the <a href="../api_cxx/env_open.html#DB_INIT_TXN">DB_INIT_TXN</a> flag, calling DbEnv::close aborts any unresolved transactions. Applications should not depend on this behavior for transactions involving Berkeley DB databases; all such transactions should be explicitly resolved. The problem with depending on this semantic is that aborting an unresolved transaction involving database operations requires a database handle. Because the database handles should have been closed before calling DbEnv::close, it will not be possible to abort the transaction, and recovery will have to be run on the Berkeley DB environment before further operations are done.</p> <p>Where log cursors were created using the <a href="../api_cxx/log_cursor.html">DbEnv::log_cursor</a> method, calling DbEnv::close does not imply closing those cursors.</p> <p>In multithreaded applications, only a single thread may call DbEnv::close.</p> <p>After DbEnv::close has been called, regardless of its return, the Berkeley DB environment handle may not be accessed again.</p> <p>The DbEnv::close method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success. </p> <b>Parameters</b> <br> <b>flags</b><ul compact><li>The <b>flags</b> parameter is currently unused, and must be set to 0.</ul> <br> <hr size=1 noshade> <br><b>Class</b> <a href="../api_cxx/env_class.html">DbEnv</a> <br><b>See Also</b> <a href="../api_cxx/env_list.html">Database Environments and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> </body> </html>