<!--$Id: env_failchk.so,v 10.6 2006/10/12 21:37:42 bostic Exp $--> <!--Copyright (c) 1997,2007 Oracle. All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DbEnv::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> <h3>DbEnv::failchk</h3> </td> <td align=right> <a href="../../db46-devel-4.6.21/api_cxx/api_core.html"><img src="../../db46-devel-4.6.21/images/api.gif" alt="API"></a> <a href="../../db46-devel-4.6.21/ref/toc.html"><img src="../../db46-devel-4.6.21/images/ref.gif" alt="Ref"></a></td> </tr></table> <hr size=1 noshade> <tt> <h3><pre> #include <db_cxx.h> <p> int DbEnv::failchk(u_int32_t flags); </pre></h3> <hr size=1 noshade> <h3>Description: DbEnv::failchk</h3> <p>The DbEnv::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="../../db46-devel-4.6.21/ref/cam/app.html">Architecting Data Store and Concurrent Data Store applications</a>, and <a href="../../db46-devel-4.6.21/ref/transapp/app.html">Architecting Transactional Data Store applications</a>.</p> <p>The DbEnv::failchk method is based on the "thread_id" and "is_alive" functions specified to the <a href="../../db46-devel-4.6.21/api_cxx/env_set_thread_id.html">DbEnv::set_thread_id</a> method. Applications calling the DbEnv::failchk method must have already called the <a href="../../db46-devel-4.6.21/api_cxx/env_set_isalive.html">DbEnv::set_isalive</a> method, on the same <a href="../../db46-devel-4.6.21/api_cxx/env_class.html">DbEnv</a>, and must have configured their database environment using the <a href="../../db46-devel-4.6.21/api_cxx/env_set_thread_count.html">DbEnv::set_thread_count</a> method.</p> <p>If DbEnv::failchk determines a thread of control exited while holding database read locks, it will release those locks. If DbEnv::failchk determines a thread of control exited with an unresolved transaction, the transaction will be aborted. In either of these cases, DbEnv::failchk will return 0 and the application may continue to use the database environment.</p> <p>In either of these cases, the DbEnv::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="../../db46-devel-4.6.21/api_cxx/env_set_msgfile.html">DbEnv::set_msgfile</a> method for more information), or passed to an application callback function (see the <a href="../../db46-devel-4.6.21/api_cxx/env_set_msgcall.html">DbEnv::set_msgcall</a> method for more information).</p> <p>If DbEnv::failchk determines a thread of control has exited such that database environment recovery is required, it will return <a href="../../db46-devel-4.6.21/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="../../db46-devel-4.6.21/ref/cam/fail.html">Handling failure in Data Store and Concurrent Data Store applications</a>, and <a href="../../db46-devel-4.6.21/ref/transapp/fail.html">Handling failure in Transactional Data Store applications</a>.</p> <p>The DbEnv::failchk method may not be called before the <a href="../../db46-devel-4.6.21/api_cxx/env_open.html">DbEnv::open</a> method has been called.</p> <p>The DbEnv::failchk 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> <h3>Parameters</h3> <dl compact> <dt><b>flags</b><dd>The <b>flags</b> parameter is currently unused, and must be set to 0. </dl> <h3>Errors</h3> <p>The DbEnv::failchk method may fail and throw <a href="../../db46-devel-4.6.21/api_cxx/except_class.html">DbException</a>, encapsulating one of the following non-zero errors, or return one of the following non-zero errors:</p> <dl compact> <dt>EINVAL<dd>An invalid flag value or parameter was specified. </dl> <hr size=1 noshade> <h3>Class</h3> <a href="../../db46-devel-4.6.21/api_cxx/env_class.html">DbEnv</a> <h3>See Also</h3> <a href="../../db46-devel-4.6.21/api_cxx/env_list.html">Database Environments and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../../db46-devel-4.6.21/api_cxx/api_core.html"><img src="../../db46-devel-4.6.21/images/api.gif" alt="API"></a><a href="../../db46-devel-4.6.21/ref/toc.html"><img src="../../db46-devel-4.6.21/images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1>Copyright (c) 1996,2007 Oracle. 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