1<!--$Id: log_file.so,v 10.34 2004/08/13 03:38:57 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: DbEnv::log_file</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> 13<b>DbEnv::log_file</b> 14</td> 15<td align=right> 16<a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a> 17<a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td> 18</tr></table> 19<hr size=1 noshade> 20<tt> 21<b><pre> 22#include <db_cxx.h> 23<p> 24int 25DbEnv::log_file(const DbLsn *lsn, char *namep, size_t len); 26</pre></b> 27<hr size=1 noshade> 28<b>Description: DbEnv::log_file</b> 29<p>The DbEnv::log_file method maps 30<a href="../api_cxx/lsn_class.html">DbLsn</a> objects 31to filenames, returning the name of the file containing the record named 32by <b>lsn</b>.</p> 33<p>This mapping of 34<a href="../api_cxx/lsn_class.html">DbLsn</a> objects 35to files is needed for database administration. For example, a 36transaction manager typically records the earliest <a href="../api_cxx/lsn_class.html">DbLsn</a> needed 37for restart, and the database administrator may want to archive log 38files to tape when they contain only <a href="../api_cxx/lsn_class.html">DbLsn</a> entries before the 39earliest one needed for restart.</p> 40<p>The DbEnv::log_file method 41either returns a non-zero error value 42or throws an exception that encapsulates a non-zero error value on 43failure, and returns 0 on success. 44</p> 45<b>Parameters</b> <br> 46 <b>lsn</b><ul compact><li>The <b>lsn</b> parameter is the 47<a href="../api_cxx/lsn_class.html">DbLsn</a> object 48for which a filename is wanted.</ul> 49 <b>namep</b><ul compact><li>The <b>namep</b> parameter references memory into which 50 the name of the file containing the record named by <b>lsn</b> is copied.</ul> 51 <b>len</b><ul compact><li>The <b>len</b> parameter is the length of the <b>namep</b> buffer in 52bytes. If <b>namep</b> is too short to hold the filename, 53DbEnv::log_file will fail. (Log filenames are normally quite short, 54on the order of 10 characters.)</ul> 55<br> 56<br><b>Errors</b> 57<p>The DbEnv::log_file method 58may fail and throw 59<a href="../api_cxx/except_class.html">DbException</a>, 60encapsulating one of the following non-zero errors, or return one of 61the following non-zero errors:</p> 62<br> 63<b>EINVAL</b><ul compact><li>If supplied buffer was too small to hold the log filename; or if an 64invalid flag value or parameter was specified.</ul> 65<br> 66<hr size=1 noshade> 67<br><b>Class</b> 68<a href="../api_cxx/env_class.html">DbEnv</a>, <a href="../api_cxx/logc_class.html">DbLogc</a>, <a href="../api_cxx/lsn_class.html">DbLsn</a> 69<br><b>See Also</b> 70<a href="../api_cxx/log_list.html">Logging Subsystem and Related Methods</a> 71</tt> 72<table width="100%"><tr><td><br></td><td align=right> 73<a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> 74</td></tr></table> 75<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 76</body> 77</html> 78
