1<!--$Id: env_set_msgcall.so,v 10.7 2006/05/17 20:47:46 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: DB_ENV->set_msgcall</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>DB_ENV->set_msgcall</b> 14</td> 15<td align=right> 16<a href="../api_c/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.h> 23<p> 24void 25DB_ENV->set_msgcall(DB_ENV *dbenv, 26 void (*db_msgcall_fcn)(const DB_ENV *dbenv, const char *msg)); 27</pre></b> 28<hr size=1 noshade> 29<b>Description: DB_ENV->set_msgcall</b> 30<p>There are interfaces in the Berkeley DB library which either directly output 31informational messages or statistical information, or configure the 32library to output such messages when performing other operations, for 33example, <a href="../api_c/env_set_verbose.html">DB_ENV->set_verbose</a> and <a href="../api_c/env_stat.html">DB_ENV->stat_print</a>.</p> 34<p>The DB_ENV->set_msgcall and DB->set_msgcall methods are used to 35pass these messages to the application, and Berkeley DB will call 36<b>db_msgcall_fcn</b> with each message. It is up to the 37<b>db_msgcall_fcn</b> function to display the message in an appropriate 38manner.</p> 39<p>Setting <b>db_msgcall_fcn</b> to NULL unconfigures the callback interface.</p> 40<p>Alternatively, you can use the <a href="../api_c/db_set_msgfile.html">DB->set_msgfile</a> or 41<a href="../api_c/env_set_msgfile.html">DB_ENV->set_msgfile</a> methods to display the messages via a C library FILE *.</p> 42<p>The DB_ENV->set_msgcall method configures operations performed using the specified 43<a href="../api_c/env_class.html">DB_ENV</a> handle, not all operations performed on the underlying 44database environment.</p> 45<p>The DB_ENV->set_msgcall method may be called at any time during the life of the 46application.</p> 47<b>Parameters</b> <br> 48 <b>db_msgcall_fcn</b><ul compact><li>The <b>db_msgcall_fcn</b> parameter is the application-specified message 49reporting function. The function takes two parameters: 50<br> 51<b><b>dbenv</b></b><ul compact><li>The <b>dbenv</b> parameter is the enclosing database environment.</ul> 52<b><b>msg</b></b><ul compact><li>The <b>msg</b> parameter is the message string.</ul> 53<br></ul> 54<p>Berkeley DB is not re-entrant. Callback functions should not attempt to make 55library calls (for example, to release locks or close open handles). 56Re-entering Berkeley DB is not guaranteed to work correctly, and the results 57are undefined.</p> 58<br> 59<hr size=1 noshade> 60<br><b>Class</b> 61<a href="../api_c/env_class.html">DB_ENV</a> 62<br><b>See Also</b> 63<a href="../api_c/env_list.html">Database Environments and Related Methods</a> 64</tt> 65<table width="100%"><tr><td><br></td><td align=right> 66<a href="../api_c/api_core.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> 67</td></tr></table> 68<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 69</body> 70</html> 71
