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
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Db::set_append_recno()</title>
<link rel="stylesheet" href="apiReference.css" type="text/css" />
<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
<link rel="start" href="index.html" title="Berkeley DB C++ API Reference" />
<link rel="up" href="db.html" title="Chapter 2. The Db Handle" />
<link rel="prev" href="dbset_alloc.html" title="Db::set_alloc()" />
<link rel="next" href="dbset_bt_compare.html" title="Db::set_bt_compare()" />
</head>
<body>
<div xmlns="" class="navheader">
<div class="libver">
<p>Library Version 11.2.5.3</p>
</div>
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">Db::set_append_recno()</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="dbset_alloc.html">Prev</a> </td>
<th width="60%" align="center">Chapter 2.
The Db Handle
</th>
<td width="20%" align="right"> <a accesskey="n" href="dbset_bt_compare.html">Next</a></td>
</tr>
</table>
<hr />
</div>
<div class="sect1" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both"><a id="dbset_append_recno"></a>Db::set_append_recno()</h2>
</div>
</div>
</div>
<pre class="programlisting">#include <db_cxx.h>
int
Db::set_append_recno(int (*db_append_recno_fcn)(DB *dbp, Dbt *data,
db_recno_t recno));</pre>
<p>
When using the <a class="link" href="dbput.html#dbput_DB_APPEND">DB_APPEND</a>
option of the <a class="xref" href="dbput.html" title="Db::put()">Db::put()</a> method, it may be
useful to modify the stored data based on the generated key. If a
callback function is specified using the
<code class="methodname">Db::set_append_recno()</code>
method, it will be called after the record number has been selected,
but before the data has been stored.
</p>
<p>
The <code class="methodname">Db::set_append_recno()</code> method configures operations performed
using the specified <a class="link" href="db.html" title="Chapter 2. The Db Handle">Db</a>
handle, not all operations performed on the underlying database.
</p>
<p>
The <code class="methodname">Db::set_append_recno()</code> method may not be called after the
<a class="xref" href="dbopen.html" title="Db::open()">Db::open()</a> method is called.
</p>
<p>
The <code class="methodname">Db::set_append_recno()</code> <span>
<span>
method either returns a non-zero error value or throws an
exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
</span>
</span>
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>
<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>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp4868328"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp4599528"></a>db_append_recno_fcn</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>db_append_recno_fcn</strong></span> parameter is
a function to call after the record number has been selected but
before the data has been stored into the database. The function takes
three parameters:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
<code class="literal">dbp</code>
</p>
<p>
The <span class="bold"><strong>dbp</strong></span> parameter is the enclosing
database handle.
</p>
</li>
<li>
<p>
<code class="literal">data</code>
</p>
<p>
The <span class="bold"><strong>data</strong></span> parameter is the data
<a class="link" href="dbt.html" title="Chapter 4. The Dbt Handle">Dbt</a> to be stored.
</p>
</li>
<li>
<p>
<code class="literal">recno</code>
</p>
<p>
The <span class="bold"><strong>recno</strong></span> parameter is the generated
record number.
</p>
</li>
</ul>
</div>
<p>
The called function may modify the data
<a class="link" href="dbt.html" title="Chapter 4. The Dbt Handle">Dbt</a>. If the function needs to allocate
memory for the <span class="bold"><strong>data</strong></span> field, the
<span class="bold"><strong>flags</strong></span> field of
the returned <a class="link" href="dbt.html" title="Chapter 4. The Dbt Handle">Dbt</a>
should be set to <code class="literal">DB_DBT_APPMALLOC</code>, which indicates that
Berkeley DB should free the memory when it is done with it.
</p>
<p>
The callback function must return 0 on success and
<span class="bold"><strong>errno</strong></span> or a value outside of
the Berkeley DB error name space on failure.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp4785640"></a>Errors</h3>
</div>
</div>
</div>
<p>
The <code class="methodname">Db::set_append_recno()</code> <span>
<span>
method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a>
exception, encapsulating one of the following non-zero errors, or return one
of the following non-zero errors:
</span>
</span>
</p>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp3919096"></a>EINVAL</h4>
</div>
</div>
</div>
<p>
If the method was called after <a class="xref" href="dbopen.html" title="Db::open()">Db::open()</a>
was called; or if an invalid flag value or parameter was specified.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp3851616"></a>Class</h3>
</div>
</div>
</div>
<p>
<a class="link" href="db.html" title="Chapter 2. The Db Handle">Db</a>
</p>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp4073016"></a>See Also</h3>
</div>
</div>
</div>
<p>
<a class="xref" href="db.html#dblist" title="Database and Related Methods">Database and Related Methods</a>
</p>
</div>
</div>
<div class="navfooter">
<hr />
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left"><a accesskey="p" href="dbset_alloc.html">Prev</a> </td>
<td width="20%" align="center">
<a accesskey="u" href="db.html">Up</a>
</td>
<td width="40%" align="right"> <a accesskey="n" href="dbset_bt_compare.html">Next</a></td>
</tr>
<tr>
<td width="40%" align="left" valign="top">Db::set_alloc() </td>
<td width="20%" align="center">
<a accesskey="h" href="index.html">Home</a>
</td>
<td width="40%" align="right" valign="top"> Db::set_bt_compare()</td>
</tr>
</table>
</div>
</body>
</html>
|
