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
|
<?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>Dynamic shared libraries</title>
<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
<link rel="start" href="index.html" title="Berkeley DB Installation and Build Guide" />
<link rel="up" href="build_unix.html" title="Chapter 7. Building Berkeley DB for UNIX/POSIX" />
<link rel="prev" href="build_unix_install.html" title="Installing Berkeley DB" />
<link rel="next" href="build_unix_test.html" title="Running the test suite under UNIX" />
</head>
<body>
<div xmlns="" class="navheader">
<div class="libver">
<p>Library Version 12.1.6.1</p>
</div>
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">Dynamic shared libraries</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="build_unix_install.html">Prev</a> </td>
<th width="60%" align="center">Chapter 7. Building Berkeley DB for UNIX/POSIX
</th>
<td width="20%" align="right"> <a accesskey="n" href="build_unix_test.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="build_unix_shlib"></a>Dynamic shared libraries</h2>
</div>
</div>
</div>
<p>
<span class="bold"><strong>Warning</strong></span>: the following
information is intended to be generic and is likely to be
correct for most UNIX systems. Unfortunately, dynamic shared
libraries are not standard between UNIX systems, so there may
be information here that is not correct for your system. If
you have problems, consult your compiler and linker manual
pages, or your system administrator.
</p>
<p>
The Berkeley DB dynamic shared libraries are created with
the name libdb-<span class="bold"><strong>major</strong></span>.<span class="bold"><strong>minor</strong></span>.
so, where <span class="bold"><strong>major</strong></span> is the major version number and
<span class="bold"><strong>minor</strong></span> is the minor
version number. Other shared libraries are created if Java and
Tcl support are enabled: specifically, libdb_java-<span class="bold"><strong>major</strong></span>.<span class="bold"><strong>minor</strong></span>.so
and libdb_tcl-<span class="bold"><strong>major</strong></span>.<span class="bold"><strong>minor</strong></span>.so.
</p>
<p>
On most UNIX systems, when any shared library is created,
the linker stamps it with a "SONAME". In the case of Berkeley
DB, the SONAME is libdb-<span class="bold"><strong>major</strong></span>.<span class="bold"><strong>minor</strong></span>.so.
It is important to realize that applications linked against a shared
library remember the SONAMEs of the libraries they use and not the
underlying names in the filesystem.
</p>
<p>
When the Berkeley DB shared library is installed, links are
created in the install lib directory so that libdb-<span class="bold"><strong>major</strong></span>.<span class="bold"><strong>minor</strong></span>.so,
libdb-<span class="bold"><strong>major</strong></span>.so, and libdb.so all refer to the same
library. This library will have an SONAME of libdb-<span class="bold"><strong>major</strong></span>.<span class="bold"><strong>minor</strong></span>.so.
</p>
<p>
Any previous versions of the Berkeley DB libraries that are
present in the install directory (such as libdb-2.7.so or
libdb-2.so) are left unchanged. (Removing or moving old shared
libraries is one drastic way to identify applications that
have been linked against those vintage releases.)
</p>
<p>
Once you have installed the Berkeley DB libraries, unless
they are installed in a directory where the linker normally
looks for shared libraries, you will need to specify the
installation directory as part of compiling and linking
against Berkeley DB. Consult your system manuals or system
administrator for ways to specify a shared library directory
when compiling and linking applications with the Berkeley DB
libraries. Many systems support environment variables (for
example, LD_LIBRARY_PATH or LD_RUN_PATH), or system
configuration files (for example, /etc/ld.so.conf) for this
purpose.
</p>
<p>
<span class="bold"><strong>Warning</strong></span>: some UNIX
installations may have an already existing
<code class="filename">/usr/lib/libdb.so</code>, and this library
may be an incompatible version of Berkeley DB.
</p>
<p>
We recommend that applications link against libdb.so (for
example, using -ldb). Even though the linker uses the file
named libdb.so, the executable file for the application
remembers the library's SONAME
(libdb-<span class="bold"><strong>major</strong></span>.<span class="bold"><strong>minor</strong></span>.so).
This has the effect of marking the applications with the versions they
need at link time. Because applications locate their needed SONAMEs when they are
executed, all previously linked applications will continue to
run using the library they were linked with, even when a new
version of Berkeley DB is installed and the file
<code class="filename">libdb.so</code> is replaced with a new
version.
</p>
<p>
Applications that know they are using features specific to
a particular Berkeley DB release can be linked to that
release. For example, an application wanting to link to
Berkeley DB major release "3" can link using -ldb-3, and
applications that know about a particular minor release number
can specify both major and minor release numbers; for example,
-ldb-3.5.
</p>
<p>
If you want to link with Berkeley DB before performing
library installation, the "make" command will have created a
shared library object in the <code class="filename">.libs</code>
subdirectory of the build directory, such as
<code class="filename">build_unix/.libs/libdb-major.minor.so</code>.
If you want to link a file against this library, with, for
example, a major number of "3" and a minor number of "5", you
should be able to do something like the following:
</p>
<pre class="programlisting">cc -L BUILD_DIRECTORY/.libs -o testprog testprog.o -ldb-3.5
env LD_LIBRARY_PATH="BUILD_DIRECTORY/.libs:$LD_LIBRARY_PATH" ./testprog</pre>
<p>
where <span class="bold"><strong>BUILD_DIRECTORY</strong></span> is
the full directory path to the directory where you built
Berkeley DB.
</p>
<p>
The libtool program (which is configured in the build
directory) can be used to set the shared library path and run
a program. For example, the following runs the gdb debugger on
the db_dump utility after setting the appropriate paths:
</p>
<pre class="programlisting">libtool gdb db_dump</pre>
<p>
Libtool may not know what to do with arbitrary commands (it
is hardwired to recognize "gdb" and some other commands). If
it complains the mode argument will usually resolve the
problem:
</p>
<pre class="programlisting">libtool --mode=execute my_debugger db_dump</pre>
<p>
On most systems, using libtool in this way is exactly
equivalent to setting the LD_LIBRARY_PATH environment variable
and then executing the program. On other systems, using
libtool has the virtue of knowing about any other details on
systems that don't behave in this typical way.
</p>
</div>
<div class="navfooter">
<hr />
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left"><a accesskey="p" href="build_unix_install.html">Prev</a> </td>
<td width="20%" align="center">
<a accesskey="u" href="build_unix.html">Up</a>
</td>
<td width="40%" align="right"> <a accesskey="n" href="build_unix_test.html">Next</a></td>
</tr>
<tr>
<td width="40%" align="left" valign="top">Installing Berkeley
DB </td>
<td width="20%" align="center">
<a accesskey="h" href="index.html">Home</a>
</td>
<td width="40%" align="right" valign="top"> Running the test suite under
UNIX</td>
</tr>
</table>
</div>
</body>
</html>
|
