1<!--$Id: enomem.so,v 1.2 2004/09/28 14:13:09 bostic Exp $--> 2<!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> 3<!--See the file LICENSE for redistribution information.--> 4<html> 5<head> 6<title>Berkeley DB Reference Guide: Release 4.3: ENOMEM and DbMemoryException</title> 7<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> 8<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> 9</head> 10<body bgcolor=white> 11<table width="100%"><tr valign=top> 12<td><b><dl><dt>Berkeley DB Reference Guide:<dd>Upgrading Berkeley DB Applications</dl></b></td> 13<td align=right><a href="../upgrade.4.3/fileopen.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../upgrade.4.3/repl.html"><img src="../../images/next.gif" alt="Next"></a> 14</td></tr></table> 15<p align=center><b>Release 4.3: ENOMEM and DbMemoryException</b></p> 16<p>In versions of Berkeley DB before 4.3, the error <b>ENOMEM</b> was used to 17indicate that the buffer in a <a href="../../api_c/dbt_class.html">DBT</a> configured with 18<a href="../../api_c/dbt_class.html#DB_DBT_USERMEM">DB_DBT_USERMEM</a> was too small to hold a key or data item being 19retrieved. The 4.3 release adds a new error, <a href="../../api_c/dbt_class.html#DB_BUFFER_SMALL">DB_BUFFER_SMALL</a>, 20that is returned in this case.</p> 21<p>The reason for the change is that the use of <b>ENOMEM</b> was 22ambiguous: calls such as <a href="../../api_c/db_get.html">DB->get</a> or <a href="../../api_c/dbc_get.html">DBcursor->get</a> could return 23<b>ENOMEM</b> either if a <a href="../../api_c/dbt_class.html">DBT</a> was too small or if some resource 24was exhausted.</p> 25<p>The result is that starting with the 4.3 release, C applications should 26always treat <b>ENOMEM</b> as a fatal error. Code that checked for 27the <b>ENOMEM</b> return and allocated a new buffer should be changed 28to check for <a href="../../api_c/dbt_class.html#DB_BUFFER_SMALL">DB_BUFFER_SMALL</a>.</p> 29<p>In C++ applications configured for exceptions, a 30<a href="../../api_cxx/memp_class.html">DbMemoryException</a> will continue to be thrown in both cases, 31and applications should check the errno in the exception to determine 32which error occurred.</p> 33<p>In Java applications, a <b>DbMemoryException</b> will be thrown 34when a <b>Dbt</b> is too small to hold a return value, and an 35<b>OutOfMemoryError</b> will be thrown in all cases of resource 36exhaustion.</p> 37<table width="100%"><tr><td><br></td><td align=right><a href="../upgrade.4.3/fileopen.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../upgrade.4.3/repl.html"><img src="../../images/next.gif" alt="Next"></a> 38</td></tr></table> 39<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 40</body> 41</html> 42
