1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
<!--$Id: db_set_errcall.so,v 10.10 2002/08/18 21:15:54 bostic Exp $-->
<!--$Id: env_set_errcall.so,v 10.39 2006/05/17 20:47:46 bostic Exp $-->
<!--Copyright 1997-2006 by Oracle Corporation-->
<!--All rights reserved.-->
<!--See the file LICENSE for redistribution information.-->
<html>
<head>
<title>Berkeley DB: Db::set_errcall</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>
<h3>Db::set_errcall</h3>
</td>
<td align=right>
<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></td>
</tr></table>
<hr size=1 noshade>
<tt>
<h3><pre>
#include <db_cxx.h>
<p>
void Db::set_errcall(void (*db_errcall_fcn)
(const DbEnv *dbenv, const char *errpfx, const char *msg));
</pre></h3>
<hr size=1 noshade>
<h3>Description: Db::set_errcall</h3>
When an error occurs in the Berkeley DB library, an exception is thrown or an
error return value is returned by the interface. In some cases,
however, the <b>errno</b> value may be insufficient to completely
describe the cause of the error, especially during initial application
debugging.
<p>The <a href="../api_cxx/env_set_errcall.html">DbEnv::set_errcall</a> and Db::set_errcall methods are used to
enhance the mechanism for reporting error messages to the application.
In some cases, when an error occurs, Berkeley DB will call
<b>db_errcall_fcn</b> with additional error information. It is up to
the <b>db_errcall_fcn</b> function to display the error message in an
appropriate manner.</p>
<p>Setting <b>db_errcall_fcn</b> to NULL unconfigures the callback interface.</p>
<p>Alternatively, you can use the <a href="../api_cxx/env_set_error_stream.html">DbEnv::set_error_stream</a> and
<a href="../api_cxx/db_set_error_stream.html">Db::set_error_stream</a> methods to display the additional information via
an output stream, or the <a href="../api_cxx/db_set_errfile.html">Db::set_errfile</a> or
<a href="../api_cxx/env_set_errfile.html">DbEnv::set_errfile</a> methods to display the additional information via a C
library FILE *. You should not mix these approaches.</p>
<p>This error-logging enhancement does not slow performance or significantly
increase application size, and may be run during normal operation as well
as during application debugging.</p>
<p>For <a href="../api_cxx/db_class.html">Db</a> handles opened inside of Berkeley DB environments, calling the
Db::set_errcall method affects the entire environment and is equivalent to calling
the <a href="../api_cxx/env_set_errcall.html">DbEnv::set_errcall</a> method.</p>
<p>The Db::set_errcall method configures operations performed using the specified
<a href="../api_cxx/db_class.html">Db</a> handle, not all operations performed on the underlying
database.</p>
<p>The Db::set_errcall method may be called at any time during the life of the
application.</p>
<h3>Parameters</h3>
<dl compact>
<dt><b>db_errcall_fcn</b><dd>The <b>db_errcall_fcn</b> parameter is the application-specified error
reporting function. The function takes three parameters:
<dl compact>
<dt><b>dbenv</b><dd>The <b>dbenv</b> parameter is the enclosing database environment.
<dt><b>errpfx</b><dd>The <b>errpfx</b> parameter is the prefix string (as previously set by
<a href="../api_cxx/db_set_errpfx.html">Db::set_errpfx</a> or <a href="../api_cxx/env_set_errpfx.html">DbEnv::set_errpfx</a>).
<dt><b>msg</b><dd>The <b>msg</b> parameter is the error message string.
</dl>
<p>Berkeley DB is not re-entrant. Callback functions should not attempt to make
library calls (for example, to release locks or close open handles).
Re-entering Berkeley DB is not guaranteed to work correctly, and the results
are undefined.</p>
</dl>
<hr size=1 noshade>
<h3>Class</h3>
<a href="../api_cxx/db_class.html">Db</a>
<h3>See Also</h3>
<a href="../api_cxx/db_list.html">Databases and Related Methods</a>
</tt>
<table width="100%"><tr><td><br></td><td align=right>
<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>
</td></tr></table>
<p><font size=1>Copyright (c) 1996-2006 Oracle Corporation - All rights reserved.</font>
</body>
</html>
|
