<!--$Id: env_set_thread_count.so,v 10.3 2007/04/02 16:08:13 bostic Exp $--> <!--Copyright (c) 1997,2007 Oracle. All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DB_ENV->set_thread_count</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>DB_ENV->set_thread_count</h3> </td> <td align=right> <a href="../../db46-devel-4.6.21/api_c/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.h> <p> int DB_ENV->set_thread_count(DB_ENV *dbenv, u_int32_t count); <p> int DB_ENV->get_thread_count(DB_ENV *dbenv, u_int32_t *countp); </pre></h3> <hr size=1 noshade> <h3>Description: DB_ENV->set_thread_count</h3> <p>Declare an approximate number of threads in the database environment. The DB_ENV->set_thread_count method must be called prior to opening the database environment if the <a href="../../db46-devel-4.6.21/api_c/env_failchk.html">DB_ENV->failchk</a> method will be used. The DB_ENV->set_thread_count method does not set the maximum number of threads but is used to determine memory sizing and the thread control block reclamation policy.</p> <p>If a process has not configured an <b>is_alive</b> function from the <a href="../../db46-devel-4.6.21/api_c/env_set_isalive.html">DB_ENV->set_isalive</a> method, and then attempts to join a database environment configured for failure checking with the <a href="../../db46-devel-4.6.21/api_c/env_failchk.html">DB_ENV->failchk</a>, <a href="../../db46-devel-4.6.21/api_c/env_set_thread_id.html">DB_ENV->set_thread_id</a>, <a href="../../db46-devel-4.6.21/api_c/env_set_isalive.html">DB_ENV->set_isalive</a> and DB_ENV->set_thread_count methods, the program may be unable to allocate a thread control block and fail to join the environment. <b>This is true of the standalone Berkeley DB utility programs.</b> To avoid problems when using the standalone Berkeley DB utility programs with environments configured for failure checking, incorporate the utility's functionality directly in the application, or call the <a href="../../db46-devel-4.6.21/api_c/env_failchk.html">DB_ENV->failchk</a> method before running the utility.</p> <p>The database environment's thread count may also be configured using the environment's <b>DB_CONFIG</b> file. The syntax of the entry in that file is a single line with the string "set_thread_count", one or more whitespace characters, and the thread count. Because the <b>DB_CONFIG</b> file is read when the database environment is opened, it will silently overrule configuration done before that time.</p> <p>The DB_ENV->set_thread_count method configures operations performed using the specified <a href="../../db46-devel-4.6.21/api_c/env_class.html">DB_ENV</a> handle, not all operations performed on the underlying database environment.</p> <p>The DB_ENV->set_thread_count method may not be called after the <a href="../../db46-devel-4.6.21/api_c/env_open.html">DB_ENV->open</a> method is called. </p> <p>The DB_ENV->set_thread_count method returns a non-zero error value on failure and 0 on success. </p> <h3>Parameters</h3> <dl compact> <dt><b>count</b><dd>The <b>count</b> parameter is an approximate thread count for the database environment. </dl> <h3>Errors</h3> <p>The DB_ENV->set_thread_count method may fail and return one of the following non-zero errors:</p> <dl compact> <dt>EINVAL<dd>If the method was called after <a href="../../db46-devel-4.6.21/api_c/env_open.html">DB_ENV->open</a> was called; or if an invalid flag value or parameter was specified. </dl> <hr size=1 noshade> <h3>Description: DB_ENV->get_thread_count</h3> <p>The DB_ENV->get_thread_count method returns the thread count.</p> <p>The DB_ENV->get_thread_count method may be called at any time during the life of the application.</p> <p>The DB_ENV->get_thread_count method returns a non-zero error value on failure and 0 on success. </p> <h3>Parameters</h3> <dl compact> <dt><b>countp</b><dd>The DB_ENV->get_thread_count method returns the thread count in <b>countp</b>. </dl> <hr size=1 noshade> <h3>Class</h3> <a href="../../db46-devel-4.6.21/api_c/env_class.html">DB_ENV</a> <h3>See Also</h3> <a href="../../db46-devel-4.6.21/api_c/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_c/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. All rights reserved.</font> </body> </html>
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