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5 <title>Libxml Frequently asqued Questions</title>
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11<h1 align="center">Libxml Frequently Asqued Questions</h1>
12
13<p>Location: <a
14href="http://xmlsoft.org/FAQ.html">http://xmlsoft.org/FAQ.html</a></p>
15
16<p>Libxml home page: <a href="http://xmlsoft.org/">http://xmlsoft.org/</a></p>
17
18<p>Mailing-list archive: <a
19href="http://xmlsoft.org/messages/">http://xmlsoft.org/messages/</a></p>
20
Daniel Veillardbe40c8b2000-07-14 12:10:59 +0000[diff] [blame]21<p>Version: $Revision$</p>
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]22
23<p>Table of Content:</p>
24<ul>
25 <li><a href="#Licence">Licence(s)</a></li>
26 <li><a href="#Installati">Installation</a></li>
27 <li><a href="#Compilatio">Compilation</a></li>
28 <li><a href="#Developper">Developper corner</a></li>
29</ul>
30
31<h2><a name="Licence">Licence</a>(s)</h2>
32<ol>
33 <li><em>Licensing Terms for libxml</em>
34 <p>libxml is released under 2 (compatible) licences:</p>
35 <ul>
36 <li>the <a href="http://www.gnu.org/copyleft/lgpl.html">LGPL</a>: GNU
37 Library General Public License</li>
38 <li>the <a
39 href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C
40 IPR</a>: very similar to the XWindow licence</li>
41 </ul>
42 </li>
43 <li><em>Can I embed libxml in a proprietary application ?</em>
44 <p>Yes. The W3C IPR allows you to also keep proprietary the changes you
45 made to libxml, but it would be graceful to provide back bugfixes and
46 improvements as patches for possible incorporation in the main
47 developement tree</p>
48 </li>
49</ol>
50
51<h2><a name="Installati">Installation</a></h2>
52<ol>
53 <li><em>Where can I get libxml</em> ?
54 <p>The original distribution comes from <a
55 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a
56 href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">gnome.org</a></p>
57 <p>Most linux and Bsd distribution includes libxml, this is probably the
58 safer way for end-users</p>
59 <p>David Doolin provides precompiled Windows versions at <a
Daniel Veillarde9202a02000-10-16 16:58:19 +0000[diff] [blame^]60 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]61 </li>
62 <li><em>I see libxml and libxml2 releases, which one should I install ?</em>
63 <ul>
64 <li>If you are not concerned by any existing backward compatibility with
65 existing application, install libxml2 only</li>
66 <li>If you are not doing development, you can safely install both.
67 usually the packages <a
68 href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a
69 href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a> are
70 compatible (this is not the case for development packages)</li>
71 <li>If you are a developper and your system provides separate packaging
72 for shared libraries and the development components, it is possible to
73 install libxml and libxml2, and depending on your development needs
74 have either <a
75 href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>
76 or <a
77 href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>
78 too</li>
79 <li>If you are developping a new application, please develop against
80 libxml2(-devel)</li>
81 </ul>
82 </li>
83 <li><em>I can't install the libxml package it conflicts with libxml0</em>
84 <p>You probably have an old libxml0 package used to provide the shared
85 library for libxml.so.0, you can probably safely remove it. Anyway the
86 libxml packages provided on <a
87 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provides
88 libxml.so.0</p>
89 </li>
90</ol>
91
92<h2><a name="Compilatio">Compilation</a></h2>
93<ol>
94 <li><em>What is the process to compile libxml ?</em>
95 <p>As most UNIX libraries libxml follows the "standard":</p>
96 <p><code>gunzip -c xxx.tar.gz | tar xvf -</code></p>
97 <p><code>cd libxml-xxxx</code></p>
98 <p><code>./configure --help</code></p>
99 <p>to see the options, then the compilation/installation proper</p>
100 <p><code>./configure [possible options]</code></p>
101 <p><code>make</code></p>
102 <p><code>make install</code></p>
103 <p>At that point you may have to rerun ldconfig or similar utility to
104 update your list of installed shared libs.</p>
105 </li>
106 <li><em>What other libraries are needed to compile/install libxml ?</em>
107 <p>Libxml does not requires any other library, the normal C ANSI API
108 should be sufficient (please report any violation to this rule you may
109 find).</p>
110 <p>However if found at configuration time libxml will deect and use the
111 following libs:</p>
112 <ul>
113 <li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a>: a
114 highly portable and available widely compression library</li>
115 <li>iconv: a powerful character encoding conversion library. It's
116 included by default on recent glibc libraries, so it doesn't need to
117 be installed specifically on linux. It seems it's now <a
118 href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part of
Daniel Veillarde9202a02000-10-16 16:58:19 +0000[diff] [blame^]119 the official UNIX</a> specification. Here is one <a
120 href="http://clisp.cons.org/~haible/packages-libiconv.html">implementation
121 of the library</a> which source can be found <a
122 href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>. </li>
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]123 </ul>
124 </li>
125 <li><em>The Makefile for the example gjobread is not generated</em>
126 <p>This is due to a circular dependancy in automake. No solution found so
127 far (if you know how to fix this the patch will be very welcome), that
128 failure won't affect the actually building of the xml library. You can
129 later go in and create the example Makefile by hand or reuse the
130 following:</p>
131 <pre>CC=gcc
132 CFLAGS=`xml-config --cflags`
133 LDFLAGS=`xml-config --libs`
134
135 all: gjobread
136
137 clean:
Daniel Veillarde9202a02000-10-16 16:58:19 +0000[diff] [blame^]138 &lt;TAB&gt;@(rm -f gjobread gjobread.o)
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]139
140 gjobread.o : gjobread.c
Daniel Veillarde9202a02000-10-16 16:58:19 +0000[diff] [blame^]141 &lt;TAB&gt;$(CC) $(CFLAGS) -c gjobread.c
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]142
143 gjobread: gjobread.o
Daniel Veillarde9202a02000-10-16 16:58:19 +0000[diff] [blame^]144 &lt;TAB&gt;$(CC) -o gjobread gjobread.o $(LDFLAGS)</pre>
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]145 </li>
146 <li><em>libxml does not compile with HP-UX's optional ANSI-C compiler</em>
147 <p>this is due to macro limitations. Try to add " -Wp,-H16800 -Ae" to the
148 CFLAGS</p>
149 <p>you can also install and use gcc instead or use a precompiled version
150 of libxml, both available from the <a
151 href="http://hpux.cae.wisc.edu/hppd/auto/summary_all.html">HP-UX Porting
152 and Archive Centre</a></p>
153 </li>
154 <li><em>make check fails on some platforms</em>
155 <p>Sometime the regression tests results don't completely match the value
156 produced by the parser, and the makefile uses diff to print the delta. On
157 some platforms the diff return breaks the compilation process, if the diff
158 is small this is probably not a serious problem</p>
159 </li>
160</ol>
161
162<h2><a name="Developper">Developper</a> corner</h2>
163<ol>
164 <li><em>I get compilation errors of existing code like when accessing
165 <strong>root</strong> or <strong>childs fields</strong> of nodes</em>
166 <p>You are compiling code developped for libxml version 1 and using a
167 libxml2 developement environment. Either switch back to libxml v1 devel or
168 even better fix the code to compile with libxml2 (or both) by <a
169 href="upgrade.html">following the instructions</a>.</p>
170 </li>
171 <li><em>I get compilation errors about non existing
172 <strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong>
173 fields</em>
174 <p>The source code you are using has been <a
175 href="upgrade.html">upgraded</a> to be able to compile with both libxml
176 and libxml2, but you need to install a more recent version: libxml(-devel)
Daniel Veillarde9202a02000-10-16 16:58:19 +0000[diff] [blame^]177 &gt;= 1.8.8 or libxml2(-devel) &gt;= 2.1.0</p>
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]178 </li>
179 <li><em>XPath implementation looks seriously broken</em>
180 <p>True, it's incomplete and the version released in 2.0.0 was nearly
181 unusable. A set of patches from <a href="http://www.picdar.co.uk/">Picdar
182 Technology</a> have been integrated in 2.1.0 fixing the most nasty bugs.
183 But there is still bugs and its incomplete. Patches and bug reports are
184 welcome. This will be worked out, XPath implementation is not abandonned,
185 just a momentary lack of time.</p>
186 </li>
187 <li><em>The example provided in the web page does not compile</em>
188 <p>It's hard to maintain the documentation in sync with the code
Daniel Veillarde9202a02000-10-16 16:58:19 +0000[diff] [blame^]189 &lt;grin/&gt; ...</p>
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]190 <p>Check the previous points 1/ and 2/ raised before, and send
191 patches.</p>
192 </li>
193 <li><em>Where can I get more examples and informations than in the web
194 page</em>
195 <p>Ideally a libxml book would be nice. I have no such plan ... But you
196 can:</p>
197 <ul>
Daniel Veillarde9202a02000-10-16 16:58:19 +0000[diff] [blame^]198 <li>check more deeply the <a href="html/libxml-lib.html">existing
199 generated doc</a></li>
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]200 <li>looks for examples of use for libxml function using the Gnome code
201 for example the following will query the full Gnome CVs base for the
202 use of the <strong>xmlAddChild()</strong> function:
203 <p><a
204 href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p>
205 <p>This may be slow, a large hardware donation to the gnome project
206 could cure this :-)</p>
207 </li>
208 <li><a
Daniel Veillarde9202a02000-10-16 16:58:19 +0000[diff] [blame^]209 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Browse
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]210 the libxml source</a>, I try to write code as clean and documented as
211 possible, so looking at it may be helpful</li>
212 </ul>
213 </li>
214 <li>What about C++ ?
215 <p>libxml is written in pure C in order to allow easy reuse on a number of
216 platforms, including embedded systems. I don't intend to convert to
217 C++.</p>
218 <p>There is however a C++ wrapper provided by Ari Johnson
Daniel Veillarde9202a02000-10-16 16:58:19 +0000[diff] [blame^]219 &lt;ari@btigate.com&gt; which may fullfill your needs:</p>
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]220 <p>Website: <a
221 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
222 <p>Download: <a
223 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
224 </li>
225 <li>How to validate a document a posteriori ?
226 <p>It is possible to validate documents which had not been validated at
227 initial parsing time or documents who have been built from scratch using
228 the API. Use the <a
Daniel Veillard32c3ad92000-07-03 13:04:50 +0000[diff] [blame]229 href="http://xmlsoft.org/html/gnome-xml-valid.html#XMLVALIDATEDTD">xmlValidateDtd()</a>
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]230 function. It is also possible to simply add a Dtd to an existing
231 document:</p>
232 <pre>xmlDocPtr doc; /* your existing document */
233 xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */
Daniel Veillarde9202a02000-10-16 16:58:19 +0000[diff] [blame^]234 dtd-&gt;name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]235
Daniel Veillarde9202a02000-10-16 16:58:19 +0000[diff] [blame^]236 doc-&gt;intSubset = dtd;
237 if (doc-&gt;children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
238 else xmlAddPrevSibling(doc-&gt;children, (xmlNodePtr)dtd);
Daniel Veillardaf743792000-07-01 11:49:28 +0000[diff] [blame]239 </pre>
240 </li>
241 <li>etc ...</li>
242</ol>
243
244<p><a href="mailto:Daniel.Veillard@w3.org">Daniel Veillard</a></p>
245
246<p>$Id$</p>
247</body>
248</html>