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: DbEnv::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>DbEnv::set_msgcall</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> 24void DbEnv::set_msgcall(void (*db_msgcall_fcn)(const DbEnv *dbenv, const char *msg)); 25</pre></b> 26<hr size=1 noshade> 27<b>Description: DbEnv::set_msgcall</b> 28<p>There are interfaces in the Berkeley DB library which either directly output 29informational messages or statistical information, or configure the 30library to output such messages when performing other operations, for 31example, <a href="../api_cxx/env_set_verbose.html">DbEnv::set_verbose</a> and <a href="../api_cxx/env_stat.html">DbEnv::stat_print</a>.</p> 32<p>The DbEnv::set_msgcall and Db::set_msgcall methods are used to 33pass these messages to the application, and Berkeley DB will call 34<b>db_msgcall_fcn</b> with each message. It is up to the 35<b>db_msgcall_fcn</b> function to display the message in an appropriate 36manner.</p> 37<p>Setting <b>db_msgcall_fcn</b> to NULL unconfigures the callback interface.</p> 38<p>Alternatively, you can use the <a href="../api_cxx/env_set_msg_stream.html">DbEnv::set_message_stream</a> and 39<a href="../api_cxx/db_set_msg_stream.html">Db::set_message_stream</a> methods to display the messages via an output 40stream, or the <a href="../api_cxx/db_set_msgfile.html">Db::set_msgfile</a> or <a href="../api_cxx/env_set_msgfile.html">DbEnv::set_msgfile</a> methods 41to display the messages via a C library FILE *.</p> 42<p>The DbEnv::set_msgcall method configures operations performed using the specified 43<a href="../api_cxx/env_class.html">DbEnv</a> handle, not all operations performed on the underlying 44database environment.</p> 45<p>The DbEnv::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_cxx/env_class.html">DbEnv</a> 62<br><b>See Also</b> 63<a href="../api_cxx/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_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> 67</td></tr></table> 68<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 69</body> 70</html> 71