<!--$Id: env_failchk.so,v 10.7 2007/09/21 20:06:01 bostic Exp $--> <!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DB_ENV->failchk</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>DB_ENV->failchk</b> </td> <td align=right> <a href="../api_c/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.h> <p> int DB_ENV->failchk(DB_ENV *dbenv, u_int32_t flags); </pre></b> <hr size=1 noshade> <b>Description: DB_ENV->failchk</b> <p>The DB_ENV->failchk method checks for threads of control (either a true thread or a process) that have exited while manipulating Berkeley DB library data structures, while holding a logical database lock, or with an unresolved transaction (that is, a transaction that was never aborted or committed). For more information, see <a href="../ref/cam/app.html">Architecting Data Store and Concurrent Data Store applications</a>, and <a href="../ref/transapp/app.html">Architecting Transactional Data Store applications</a>.</p> <p>The DB_ENV->failchk method is based on the "thread_id" and "is_alive" functions specified to the <a href="../api_c/env_set_thread_id.html">DB_ENV->set_thread_id</a> method. Applications calling the DB_ENV->failchk method must have already called the <a href="../api_c/env_set_isalive.html">DB_ENV->set_isalive</a> method, on the same <a href="../api_c/env_class.html">DB_ENV</a>, and must have configured their database environment using the <a href="../api_c/env_set_thread_count.html">DB_ENV->set_thread_count</a> method.</p> <p>If DB_ENV->failchk determines a thread of control exited while holding database read locks, it will release those locks. If DB_ENV->failchk determines a thread of control exited with an unresolved transaction, the transaction will be aborted. In either of these cases, DB_ENV->failchk will return 0 and the application may continue to use the database environment.</p> <p>In either of these cases, the DB_ENV->failchk method will also report the process and thread IDs associated with any released locks or aborted transactions. The information is printed to a specified output channel (see the <a href="../api_c/env_set_msgfile.html">DB_ENV->set_msgfile</a> method for more information), or passed to an application callback function (see the <a href="../api_c/env_set_msgcall.html">DB_ENV->set_msgcall</a> method for more information).</p> <p>If DB_ENV->failchk determines a thread of control has exited such that database environment recovery is required, it will return <a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a>. In this case, the application should not continue to use the database environment. For a further description as to the actions the application should take when this failure occurs, see <a href="../ref/cam/fail.html">Handling failure in Data Store and Concurrent Data Store applications</a>, and <a href="../ref/transapp/fail.html">Handling failure in Transactional Data Store applications</a>.</p> <p>The DB_ENV->failchk method may not be called before the <a href="../api_c/env_open.html">DB_ENV->open</a> method is called.</p> <p>The DB_ENV->failchk method returns a non-zero error value on failure and 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> <br><b>Errors</b> <p>The DB_ENV->failchk method may fail and return one of the following non-zero errors:</p> <br> <b>EINVAL</b><ul compact><li>An invalid flag value or parameter was specified.</ul> <br> <hr size=1 noshade> <br><b>Class</b> <a href="../api_c/env_class.html">DB_ENV</a> <br><b>See Also</b> <a href="../api_c/env_list.html">Database Environments and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../api_c/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>