<!--$Id: callback.so,v 1.5 2000/10/26 15:20:40 bostic Exp $--> <!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB Reference Guide: Release 3.2: DB callback functions, app_private field</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><dl><dt>Berkeley DB Reference Guide:<dd>Upgrading Berkeley DB Applications</dl></b></td> <td align=right><a href="../upgrade.3.2/set_flags.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../upgrade.3.2/renumber.html"><img src="../../images/next.gif" alt="Next"></a> </td></tr></table> <p align=center><b>Release 3.2: DB callback functions, app_private field</b></p> <p>In the Berkeley DB 3.2 release, four application callback functions (the callback functions set by <a href="../../api_c/db_set_bt_compare.html">DB->set_bt_compare</a>, <a href="../../api_c/db_set_bt_prefix.html">DB->set_bt_prefix</a>, <a href="../../api_c/db_set_dup_compare.html">DB->set_dup_compare</a> and <a href="../../api_c/db_set_h_hash.html">DB->set_h_hash</a>) were modified to take a reference to a <a href="../../api_c/db_class.html">DB</a> object as their first argument. This change allows the Berkeley DB Java API to reasonably support these interfaces. There is currently no need for the callback functions to do anything with this additional argument.</p> <p>C and C++ applications that specify their own Btree key comparison, Btree prefix comparison, duplicate data item comparison or Hash functions should modify these functions to take a reference to a <a href="../../api_c/db_class.html">DB</a> structure as their first argument. No further change is required.</p> <p>The app_private field of the <a href="../../api_c/dbt_class.html">DBT</a> structure (accessible only from the Berkeley DB C API) has been removed in the 3.2 release. It was replaced with app_private fields in the <a href="../../api_c/env_class.html">DB_ENV</a> and <a href="../../api_c/db_class.html">DB</a> handles. Applications using this field will have to convert to using one of the replacement fields.</p> <table width="100%"><tr><td><br></td><td align=right><a href="../upgrade.3.2/set_flags.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../upgrade.3.2/renumber.html"><img src="../../images/next.gif" alt="Next"></a> </td></tr></table> <p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> </body> </html>