<!--$Id: db_set_h_nelem.so,v 10.22 2002/08/18 21:15:56 bostic Exp $--> <!--Copyright 1997-2002 by Sleepycat Software, Inc.--> <!--All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DB->set_h_nelem</title> <meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> <meta name="keywords" content="embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++"> </head> <body bgcolor=white> <a name="2"><!--meow--></a> <table width="100%"><tr valign=top> <td> <h1>DB->set_h_nelem</h1> </td> <td align=right> <a href="../../db4-devel-4.1.25/api_c/c_index.html"><img src="../../db4-4.1.25/images/api.gif" alt="API"></a><a href="../reftoc.html"><img src="../../db4-4.1.25/images/ref.gif" alt="Ref"></a> </td></tr></table> <hr size=1 noshade> <tt> <h3><pre> #include <db.h> <p> int DB->set_h_nelem(DB *db, u_int32_t h_nelem); </pre></h3> <h1>Description</h1> <p>Set an estimate of the final size of the hash table. <p>In order for the estimate to be used when creating the database, the <a href="../../db4-devel-4.1.25/api_c/db_set_h_ffactor.html">DB->set_h_ffactor</a> method must also be called. If the estimate or fill factor are not set or are set too low, hash tables will still expand gracefully as keys are entered, although a slight performance degradation may be noticed. <p>The DB->set_h_nelem method configures a database, not only operations performed using the specified <a href="../../db4-devel-4.1.25/api_c/db_class.html">DB</a> handle. <p>The DB->set_h_nelem interface may not be called after the <a href="../../db4-devel-4.1.25/api_c/db_open.html">DB->open</a> interface is called. If the database already exists when <a href="../../db4-devel-4.1.25/api_c/db_open.html">DB->open</a> is called, the information specified to DB->set_h_nelem will be ignored. <p>The DB->set_h_nelem method returns a non-zero error value on failure and 0 on success. <h1>Errors</h1> <p>The DB->set_h_nelem method may fail and return a non-zero error for the following conditions: <p><dl compact> <p><dt>EINVAL<dd>An invalid flag value or parameter was specified. <p>Called after <a href="../../db4-devel-4.1.25/api_c/db_open.html">DB->open</a> was called. </dl> <p>The DB->set_h_nelem method may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions. If a catastrophic error has occurred, the DB->set_h_nelem method may fail and return <a href="../../db4-devel-4.1.25/ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a>, in which case all subsequent Berkeley DB calls will fail in the same way. <h1>Class</h1> <a href="../../db4-devel-4.1.25/api_c/db_class.html">DB</a> <h1>See Also</h1> <a href="../../db4-devel-4.1.25/api_c/db_list.html">Databases and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../../db4-devel-4.1.25/api_c/c_index.html"><img src="../../db4-4.1.25/images/api.gif" alt="API"></a><a href="../reftoc.html"><img src="../../db4-4.1.25/images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1><a href="http://www.sleepycat.com">Copyright Sleepycat Software</a></font> </body> </html>