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
|
<?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_env_set_func_file_map</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="setfunc.html" title="Appendix C. Berkeley DB Application Space Static Functions" />
<link rel="prev" href="db_env_set_func_exists.html" title="db_env_set_func_exists" />
<link rel="next" href="db_env_set_func_free.html" title="db_env_set_func_free" />
</head>
<body>
<div class="navheader">
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">db_env_set_func_file_map</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="db_env_set_func_exists.html">Prev</a> </td>
<th width="60%" align="center">Appendix C.
Berkeley DB Application Space Static Functions
</th>
<td width="20%" align="right"> <a accesskey="n" href="db_env_set_func_free.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="db_env_set_func_file_map"></a>db_env_set_func_file_map</h2>
</div>
</div>
</div>
<pre class="programlisting">#include <db.h>
int
db_env_set_func_file_map(int (*func_file_map)(DB_ENV *dbenv, char *path,
size_t len, int is_rdonly, void **addr),
int (*func_file_unmap)(DB_ENV *dbenv, void *addr)); </pre>
<p>
The Berkeley DB library optionally uses the ability to map a file into
memory.
</p>
<p>
The <code class="function">db_env_set_func_file_map()</code> function configures all operations
performed by a process and all of its threads of control, not
operations confined to a single database environment.
</p>
<p>
Although the <code class="function">db_env_set_func_file_map()</code> function may be called at any time
during the life of the application, it should normally be called
before making calls to the <a class="xref" href="envcreate.html" title="db_env_create">db_env_create</a> or
<a class="xref" href="dbcreate.html" title="db_create">db_create</a> methods.
</p>
<p>
The <code class="function">db_env_set_func_file_map()</code> <span>
function returns a non-zero error value on failure and 0 on success.
</span>
</p>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp55216896"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp55217088"></a>func_file_map</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>func_file_map</strong></span> parameter is the
function which maps a file into memory. The function takes 5
parameters:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
<span class="bold"><strong>dbenv</strong></span>
</p>
<p>
The <span class="bold"><strong>dbenv</strong></span> parameter is the enclosing
database environment handle.
</p>
</li>
<li>
<p>
<span class="bold"><strong>path</strong></span>
</p>
<p>
The <span class="bold"><strong>path</strong></span> parameter is the name of
file. Repeated requests for the mapping of the same name should
return a reference to the same memory.
</p>
</li>
<li>
<p>
<span class="bold"><strong>len</strong></span>
</p>
<p>
The <span class="bold"><strong>len</strong></span> parameter is the length, in
bytes, of the file.
</p>
</li>
<li>
<p>
<span class="bold"><strong>is_rdonly</strong></span>
</p>
<p>
The <span class="bold"><strong>is_rdonly</strong></span> parameter will be
non-zero if the mapped file is read-only.
</p>
</li>
<li>
<p>
<span class="bold"><strong>addr</strong></span>
</p>
<p>
The <span class="bold"><strong>addr</strong></span> parameter is the memory
location into which a pointer to the mapped file is returned.
</p>
</li>
</ul>
</div>
<p>
The <span class="bold"><strong>func_file_map</strong></span> function must
return the value of <span class="bold"><strong>errno</strong></span> on failure
and 0 on success.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp55201664"></a>func_file_unmap</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>func_file_unmap</strong></span> parameter is the
function which unmaps a file from memory. The function takes 2
parameters:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
<span class="bold"><strong>dbenv</strong></span>
</p>
<p>
The <span class="bold"><strong>dbenv</strong></span> parameter is the enclosing
database environment handle.
</p>
</li>
<li>
<p>
<code class="literal">addr</code>
</p>
<p>
The <span class="bold"><strong>addr</strong></span> parameter is the value
returned by the <span class="bold"><strong>func_file_map</strong></span>
function when the file or region was mapped into memory.
</p>
</li>
</ul>
</div>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp55233520"></a>See Also</h3>
</div>
</div>
</div>
<p>
<a href="../../programmer_reference/program_runtime.html" class="olink">Run-time configuration</a>
</p>
</div>
</div>
<div class="navfooter">
<hr />
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left"><a accesskey="p" href="db_env_set_func_exists.html">Prev</a> </td>
<td width="20%" align="center">
<a accesskey="u" href="setfunc.html">Up</a>
</td>
<td width="40%" align="right"> <a accesskey="n" href="db_env_set_func_free.html">Next</a></td>
</tr>
<tr>
<td width="40%" align="left" valign="top">db_env_set_func_exists </td>
<td width="20%" align="center">
<a accesskey="h" href="index.html">Home</a>
</td>
<td width="40%" align="right" valign="top"> db_env_set_func_free</td>
</tr>
</table>
</div>
</body>
</html>
|
