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<h1 align="center">The XML C parser and toolkit of Gnome</h1>
<h1>Note: this is the flat content of the <a
href="index.html">website</a></h1>
<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1>
<p></p>
<p
style="text-align: right; font-style: italic; font-size: 10pt">"Programmingwith
libxml2 is like the thrilling embrace of an exotic stranger." <a
href="http://diveintomark.org/archives/2004/02/18/libxml2">MarkPilgrim</a></p>
<p>Libxml2 is the XML C parser and toolkit developed for the Gnome
project(but usable outside of the Gnome platform), it is free software
availableunder the <a
href="http://www.opensource.org/licenses/mit-license.html">MITLicense</a>.
XML itself is a metalanguage to design markup languages, i.e.text language
where semantic and structure are added to the content usingextra "markup"
information enclosed between angle brackets. HTML is the mostwell-known
markup language. Though the library is written in C <a href="python.html">a
variety of language bindings</a>make it available inother environments.</p>
<p>Libxml2 is known to be very portable, the library should build and
workwithout serious troubles on a variety of systems (Linux, Unix,
Windows,CygWin, MacOS, MacOS X, RISC Os, OS/2, VMS, QNX, MVS, ...)</p>
<p>Libxml2 implements a number of existing standards related to
markuplanguages:</p>
<ul>
<li>the XML standard: <a
href="http://www.w3.org/TR/REC-xml">http://www.w3.org/TR/REC-xml</a></li>
<li>Namespaces in XML: <a
href="http://www.w3.org/TR/REC-xml-names/">http://www.w3.org/TR/REC-xml-names/</a></li>
<li>XML Base: <a
href="http://www.w3.org/TR/xmlbase/">http://www.w3.org/TR/xmlbase/</a></li>
<li><a href="http://www.cis.ohio-state.edu/rfc/rfc2396.txt">RFC
2396</a>:Uniform Resource Identifiers <a
href="http://www.ietf.org/rfc/rfc2396.txt">http://www.ietf.org/rfc/rfc2396.txt</a></li>
<li>XML Path Language (XPath) 1.0: <a
href="http://www.w3.org/TR/xpath">http://www.w3.org/TR/xpath</a></li>
<li>HTML4 parser: <a
href="http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</a></li>
<li>XML Pointer Language (XPointer) Version 1.0: <a
href="http://www.w3.org/TR/xptr">http://www.w3.org/TR/xptr</a></li>
<li>XML Inclusions (XInclude) Version 1.0: <a
href="http://www.w3.org/TR/xinclude/">http://www.w3.org/TR/xinclude/</a></li>
<li>ISO-8859-x encodings, as well as <a
href="http://www.cis.ohio-state.edu/rfc/rfc2044.txt">rfc2044</a>[UTF-8]and
<a
href="http://www.cis.ohio-state.edu/rfc/rfc2781.txt">rfc2781</a>[UTF-16]
Unicode encodings, and more if using iconv support</li>
<li>part of SGML Open Technical Resolution TR9401:1997</li>
<li>XML Catalogs Working Draft 06 August 2001: <a
href="http://www.oasis-open.org/committees/entity/spec-2001-08-06.html">http://www.oasis-open.org/committees/entity/spec-2001-08-06.html</a></li>
<li>Canonical XML Version 1.0: <a
href="http://www.w3.org/TR/xml-c14n">http://www.w3.org/TR/xml-c14n</a>and
the Exclusive XML Canonicalization CR draft <a
href="http://www.w3.org/TR/xml-exc-c14n">http://www.w3.org/TR/xml-exc-c14n</a></li>
<li>Relax NG, ISO/IEC 19757-2:2003, <a
href="http://www.oasis-open.org/committees/relax-ng/spec-20011203.html">http://www.oasis-open.org/committees/relax-ng/spec-20011203.html</a></li>
<li>W3C XML Schemas Part 2: Datatypes <a
href="http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/">REC 02
May2001</a></li>
<li>W3C <a href="http://www.w3.org/TR/xml-id/">xml:id</a>Working Draft
7April 2004</li>
</ul>
<p>In most cases libxml2 tries to implement the specifications in arelatively
strictly compliant way. As of release 2.4.16, libxml2 passed all1800+ tests
from the <a
href="http://www.oasis-open.org/committees/xml-conformance/">OASIS XML
TestsSuite</a>.</p>
<p>To some extent libxml2 provides support for the following
additionalspecifications but doesn't claim to implement them completely:</p>
<ul>
<li>Document Object Model (DOM) <a
href="http://www.w3.org/TR/DOM-Level-2-Core/">http://www.w3.org/TR/DOM-Level-2-Core/</a>the
document model, but it doesn't implement the API itself, gdome2 doesthis
on top of libxml2</li>
<li><a href="http://www.cis.ohio-state.edu/rfc/rfc959.txt">RFC
959</a>:libxml2 implements a basic FTP client code</li>
<li><a href="http://www.cis.ohio-state.edu/rfc/rfc1945.txt">RFC
1945</a>:HTTP/1.0, again a basic HTTP client code</li>
<li>SAX: a SAX2 like interface and a minimal SAX1 implementation
compatiblewith early expat versions</li>
</ul>
<p>A partial implementation of <a
href="http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/">XML Schemas Part1:
Structure</a>is being worked on but it would be far too early to make
anyconformance statement about it at the moment.</p>
<p>Separate documents:</p>
<ul>
<li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a>providing
animplementation of XSLT 1.0 and common extensions like EXSLT
forlibxml2</li>
<li><a href="http://www.cs.unibo.it/~casarini/gdome2/">the gdome2 page</a>:
a standard DOM2 implementation for libxml2</li>
<li><a href="http://www.aleksey.com/xmlsec/">the XMLSec page</a>:
animplementation of <a href="http://www.w3.org/TR/xmldsig-core/">W3C
XMLDigital Signature</a>for libxml2</li>
<li>also check the related links section below for more related and
activeprojects.</li>
</ul>
<!----------------<p>Results of the <a
href="http://xmlbench.sourceforge.net/results/benchmark/index.html">xmlbench
benchmark</a> on sourceforge February 2004 (smaller is better):</p>
<p align="center"><img src="benchmark.png"
alt="benchmark results for Expat Xerces libxml2 Oracle and Sun toolkits"></p>
-------------->
<p>Logo designed by <a href="mailto:liyanage@access.ch">Marc Liyanage</a>.</p>
<h2><a name="Introducti">Introduction</a></h2>
<p>This document describes libxml, the <a
href="http://www.w3.org/XML/">XML</a>C parser and toolkit developed for the<a
href="http://www.gnome.org/">Gnome</a>project. <a
href="http://www.w3.org/XML/">XML is a standard</a>for building
tag-basedstructured documents/data.</p>
<p>Here are some key points about libxml:</p>
<ul>
<li>Libxml2 exports Push (progressive) and Pull (blocking) type
parserinterfaces for both XML and HTML.</li>
<li>Libxml2 can do DTD validation at parse time, using a parsed
documentinstance, or with an arbitrary DTD.</li>
<li>Libxml2 includes complete <a
href="http://www.w3.org/TR/xpath">XPath</a>, <a
href="http://www.w3.org/TR/xptr">XPointer</a>and <a
href="http://www.w3.org/TR/xinclude">XInclude</a>implementations.</li>
<li>It is written in plain C, making as few assumptions as possible,
andsticking closely to ANSI C/POSIX for easy embedding. Works
onLinux/Unix/Windows, ported to a number of other platforms.</li>
<li>Basic support for HTTP and FTP client allowing applications to
fetchremote resources.</li>
<li>The design is modular, most of the extensions can be compiled out.</li>
<li>The internal document representation is as close as possible to the <a
href="http://www.w3.org/DOM/">DOM</a>interfaces.</li>
<li>Libxml2 also has a <a
href="http://www.megginson.com/SAX/index.html">SAX like interface</a>;the
interface is designed to be compatible with <a
href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
<li>This library is released under the <a
href="http://www.opensource.org/licenses/mit-license.html">MITLicense</a>.
See the Copyright file in the distribution for the precisewording.</li>
</ul>
<p>Warning: unless you are forced to because your application links with
aGnome-1.X library requiring it, <strong><span
style="background-color: #FF0000">Do Not Use libxml1</span></strong>,
uselibxml2</p>
<h2><a name="FAQ">FAQ</a></h2>
<p>Table of Contents:</p>
<ul>
<li><a href="FAQ.html#License">License(s)</a></li>
<li><a href="FAQ.html#Installati">Installation</a></li>
<li><a href="FAQ.html#Compilatio">Compilation</a></li>
<li><a href="FAQ.html#Developer">Developer corner</a></li>
</ul>
<h3><a name="License">License</a>(s)</h3>
<ol>
<li><em>Licensing Terms for libxml</em>
<p>libxml2 is released under the <a
href="http://www.opensource.org/licenses/mit-license.html">MITLicense</a>;
see the file Copyright in the distribution for the precisewording</p>
</li>
<li><em>Can I embed libxml2 in a proprietary application ?</em>
<p>Yes. The MIT License allows you to keep proprietary the changes
youmade to libxml, but it would be graceful to send-back bug fixes
andimprovements as patches for possible incorporation in the
maindevelopment tree.</p>
</li>
</ol>
<h3><a name="Installati">Installation</a></h3>
<ol>
<li><strong><span style="background-color: #FF0000">Do Not
Uselibxml1</span></strong>, use libxml2</li>
<li><em>Where can I get libxml</em>?
<p>The original distribution comes from <a
href="ftp://xmlsoft.org/libxml2/">xmlsoft.org</a>or <a
href="ftp://ftp.gnome.org/pub/GNOME/sources/libxml2/2.6/">gnome.org</a></p>
<p>Most Linux and BSD distributions include libxml, this is probably
thesafer way for end-users to use libxml.</p>
<p>David Doolin provides precompiled Windows versions at <a
href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
</li>
<li><em>I see libxml and libxml2 releases, which one should I install ?</em>
<ul>
<li>If you are not constrained by backward compatibility issues
withexisting applications, install libxml2 only</li>
<li>If you are not doing development, you can safely install
both.Usually the packages <a
href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a>and <a
href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a>arecompatible
(this is not the case for development packages).</li>
<li>If you are a developer and your system provides separate
packagingfor shared libraries and the development components, it is
possibleto install libxml and libxml2, and also <a
href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>and
<a
href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>too
for libxml2 &gt;= 2.3.0</li>
<li>If you are developing a new application, please develop
againstlibxml2(-devel)</li>
</ul>
</li>
<li><em>I can't install the libxml package, it conflicts with libxml0</em>
<p>You probably have an old libxml0 package used to provide the
sharedlibrary for libxml.so.0, you can probably safely remove it. The
libxmlpackages provided on <a
href="ftp://xmlsoft.org/libxml2/">xmlsoft.org</a>providelibxml.so.0</p>
</li>
<li><em>I can't install the libxml(2) RPM package due to
faileddependencies</em>
<p>The most generic solution is to re-fetch the latest src.rpm ,
andrebuild it locally with</p>
<p><code>rpm --rebuild libxml(2)-xxx.src.rpm</code>.</p>
<p>If everything goes well it will generate two binary rpm packages
(oneproviding the shared libs and xmllint, and the other one, the
-develpackage, providing includes, static libraries and scripts needed to
buildapplications with libxml(2)) that you can install locally.</p>
</li>
</ol>
<h3><a name="Compilatio">Compilation</a></h3>
<ol>
<li><em>What is the process to compile libxml2 ?</em>
<p>As most UNIX libraries libxml2 follows the "standard":</p>
<p><code>gunzip -c xxx.tar.gz | tar xvf -</code></p>
<p><code>cd libxml-xxxx</code></p>
<p><code>./configure --help</code></p>
<p>to see the options, then the compilation/installation proper</p>
<p><code>./configure [possible options]</code></p>
<p><code>make</code></p>
<p><code>make install</code></p>
<p>At that point you may have to rerun ldconfig or a similar utility
toupdate your list of installed shared libs.</p>
</li>
<li><em>What other libraries are needed to compile/install libxml2 ?</em>
<p>Libxml2 does not require any other library, the normal C ANSI
APIshould be sufficient (please report any violation to this rule you
mayfind).</p>
<p>However if found at configuration time libxml2 will detect and use
thefollowing libs:</p>
<ul>
<li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a>:
ahighly portable and available widely compression library.</li>
<li>iconv: a powerful character encoding conversion library. It
isincluded by default in recent glibc libraries, so it doesn't need
tobe installed specifically on Linux. It now seems a <a
href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">partof
the official UNIX</a>specification. Here is one <a
href="http://www.gnu.org/software/libiconv/">implementation of
thelibrary</a>which source can be found <a
href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>.</li>
</ul>
</li>
<li><em>Make check fails on some platforms</em>
<p>Sometimes the regression tests' results don't completely match
thevalue produced by the parser, and the makefile uses diff to print
thedelta. On some platforms the diff return breaks the compilation
process;if the diff is small this is probably not a serious problem.</p>
<p>Sometimes (especially on Solaris) make checks fail due to
limitationsin make. Try using GNU-make instead.</p>
</li>
<li><em>I use the CVS version and there is no configure script</em>
<p>The configure script (and other Makefiles) are generated. Use
theautogen.sh script to regenerate the configure script and
Makefiles,like:</p>
<p><code>./autogen.sh --prefix=/usr --disable-shared</code></p>
</li>
<li><em>I have troubles when running make tests with gcc-3.0</em>
<p>It seems the initial release of gcc-3.0 has a problem with
theoptimizer which miscompiles the URI module. Please use
anothercompiler.</p>
</li>
</ol>
<h3><a name="Developer">Developer</a>corner</h3>
<ol>
<li><em>Troubles compiling or linking programs using libxml2</em>
<p>Usually the problem comes from the fact that the compiler doesn't
getthe right compilation or linking flags. There is a small shell
script<code>xml2-config</code>which is installed as part of libxml2
usualinstall process which provides those flags. Use</p>
<p><code>xml2-config --cflags</code></p>
<p>to get the compilation flags and</p>
<p><code>xml2-config --libs</code></p>
<p>to get the linker flags. Usually this is done directly from
theMakefile as:</p>
<p><code>CFLAGS=`xml2-config --cflags`</code></p>
<p><code>LIBS=`xml2-config --libs`</code></p>
</li>
<li><em>I want to install my own copy of libxml2 in my home directory
andlink my programs against it, but it doesn't work</em>
<p>There are many different ways to accomplish this. Here is one way
todo this under Linux. Suppose your home directory is
<code>/home/user.</code>Then:</p>
<ul>
<li>Create a subdirectory, let's call it <code>myxml</code></li>
<li>unpack the libxml2 distribution into that subdirectory</li>
<li>chdir into the unpacked distribution(<code>/home/user/myxml/libxml2
</code>)</li>
<li>configure the library using the "<code>--prefix</code>"
switch,specifying an installation subdirectory
in<code>/home/user/myxml</code>, e.g.
<p><code>./configure --prefix
/home/user/myxml/xmlinst</code>{otherconfiguration options}</p>
</li>
<li>now run <code>make</code>followed by <code>make install</code></li>
<li>At this point, the installation subdirectory contains the
complete"private" include files, library files and binary program
files (e.g.xmllint), located in
<p><code>/home/user/myxml/xmlinst/lib,/home/user/myxml/xmlinst/include
</code>and <code>/home/user/myxml/xmlinst/bin</code></p>
respectively.</li>
<li>In order to use this "private" library, you should first add it
tothe beginning of your default PATH (so that your own private
programfiles such as xmllint will be used instead of the normal
systemones). To do this, the Bash command would be
<p><code>export PATH=/home/user/myxml/xmlinst/bin:$PATH</code></p>
</li>
<li>Now suppose you have a program <code>test1.c</code>that you
wouldlike to compile with your "private" library. Simply compile it
usingthe command
<p><code>gcc `xml2-config --cflags --libs` -o test test.c</code></p>
Note that, because your PATH has been set with
<code>/home/user/myxml/xmlinst/bin</code>at the beginning, the
xml2-configprogram which you just installed will be used instead of
the systemdefault one, and this will <em>automatically</em>get the
correctlibraries linked with your program.</li>
</ul>
</li>
<p></p>
<li><em>xmlDocDump() generates output on one line.</em>
<p>Libxml2 will not <strong>invent</strong>spaces in the content of
adocument since <strong>all spaces in the content of a document
aresignificant</strong>. If you build a tree from the API and
wantindentation:</p>
<ol>
<li>the correct way is to generate those yourself too.</li>
<li>the dangerous way is to ask libxml2 to add those blanks to
yourcontent <strong>modifying the content of your document in
theprocess</strong>. The result may not be what you expect. There
is<strong>NO</strong>way to guarantee that such a modification
won'taffect other parts of the content of your document. See <a
href="http://xmlsoft.org/html/libxml-parser.html#xmlKeepBlanksDefault">xmlKeepBlanksDefault()</a>and
<a
href="http://xmlsoft.org/html/libxml-tree.html#xmlSaveFormatFile">xmlSaveFormatFile()</a></li>
</ol>
</li>
<li>Extra nodes in the document:
<p><em>For a XML file as below:</em></p>
<pre>&lt;?xml version="1.0"?&gt;
&lt;PLAN xmlns="http://www.argus.ca/autotest/1.0/"&gt;
&lt;NODE CommFlag="0"/&gt;
&lt;NODE CommFlag="1"/&gt;
&lt;/PLAN&gt;</pre>
<p><em>after parsing it with the
functionpxmlDoc=xmlParseFile(...);</em></p>
<p><em>I want to the get the content of the first node (node with
theCommFlag="0")</em></p>
<p><em>so I did it as following;</em></p>
<pre>xmlNodePtr pnode;
pnode=pxmlDoc-&gt;children-&gt;children;</pre>
<p><em>but it does not work. If I change it to</em></p>
<pre>pnode=pxmlDoc-&gt;children-&gt;children-&gt;next;</pre>
<p><em>then it works. Can someone explain it to me.</em></p>
<p></p>
<p>In XML all characters in the content of the document are
significant<strong>including blanks and formatting line
breaks</strong>.</p>
<p>The extra nodes you are wondering about are just that, text nodes
withthe formatting spaces which are part of the document but that people
tendto forget. There is a function <a
href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault()</a>to
remove those at parse time, but that's an heuristic, and itsuse should be
limited to cases where you are certain there is nomixed-content in the
document.</p>
</li>
<li><em>I get compilation errors of existing code like when
accessing<strong>root</strong>or <strong>child fields</strong>of
nodes.</em>
<p>You are compiling code developed for libxml version 1 and using
alibxml2 development environment. Either switch back to libxml v1 devel
oreven better fix the code to compile with libxml2 (or both) by <a
href="upgrade.html">following the instructions</a>.</p>
</li>
<li><em>I get compilation errors about non
existing<strong>xmlRootNode</strong>or
<strong>xmlChildrenNode</strong>fields.</em>
<p>The source code you are using has been <a
href="upgrade.html">upgraded</a>to be able to compile with both libxmland
libxml2, but you need to install a more recent version:libxml(-devel)
&gt;= 1.8.8 or libxml2(-devel) &gt;= 2.1.0</p>
</li>
<li><em>XPath implementation looks seriously broken</em>
<p>XPath implementation prior to 2.3.0 was really incomplete. Upgrade toa
recent version, there are no known bugs in the current version.</p>
</li>
<li><em>The example provided in the web page does not compile.</em>
<p>It's hard to maintain the documentation in sync with the
code&lt;grin/&gt; ...</p>
<p>Check the previous points 1/ and 2/ raised before, and please
sendpatches.</p>
</li>
<li><em>Where can I get more examples and information than provided on
theweb page?</em>
<p>Ideally a libxml2 book would be nice. I have no such plan ... But
youcan:</p>
<ul>
<li>check more deeply the <a
href="html/libxml-lib.html">existinggenerated doc</a></li>
<li>have a look at <a href="examples/index.html">the set
ofexamples</a>.</li>
<li>look for examples of use for libxml2 function using the Gnome
code.For example the following will query the full Gnome CVS base for
theuse of the <strong>xmlAddChild()</strong>function:
<p><a
href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p>
<p>This may be slow, a large hardware donation to the gnome
projectcould cure this :-)</p>
</li>
<li><a
href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Browsethe
libxml2 source</a>, I try to write code as clean and documentedas
possible, so looking at it may be helpful. In particular the codeof
xmllint.c and of the various testXXX.c test programs shouldprovide
good examples of how to do things with the library.</li>
</ul>
</li>
<li>What about C++ ?
<p>libxml2 is written in pure C in order to allow easy reuse on a
numberof platforms, including embedded systems. I don't intend to convert
toC++.</p>
<p>There is however a C++ wrapper which may fulfill your needs:</p>
<ul>
<li>by Ari Johnson &lt;ari@btigate.com&gt;:
<p>Website: <a
href="http://libxmlplusplus.sourceforge.net/">http://libxmlplusplus.sourceforge.net/</a></p>
<p>Download: <a
href="http://sourceforge.net/project/showfiles.php?group_id=12999">http://sourceforge.net/project/showfiles.php?group_id=12999</a></p>
</li>
<!-- Website is currently unavailable as of 2003-08-02
<li>by Peter Jones &lt;pjones@pmade.org&gt;
<p>Website: <a
href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
</li>
-->
</ul>
</li>
<li>How to validate a document a posteriori ?
<p>It is possible to validate documents which had not been validated
atinitial parsing time or documents which have been built from
scratchusing the API. Use the <a
href="http://xmlsoft.org/html/libxml-valid.html#xmlValidateDtd">xmlValidateDtd()</a>function.
It is also possible to simply add a DTD to an existingdocument:</p>
<pre>xmlDocPtr doc; /* your existing document */
xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */
dtd-&gt;name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */
doc-&gt;intSubset = dtd;
if (doc-&gt;children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
else xmlAddPrevSibling(doc-&gt;children, (xmlNodePtr)dtd);
</pre>
</li>
<li>So what is this funky "xmlChar" used all the time?
<p>It is a null terminated sequence of utf-8 characters. And only
utf-8!You need to convert strings encoded in different ways to utf-8
beforepassing them to the API. This can be accomplished with the iconv
libraryfor instance.</p>
</li>
<li>etc ...</li>
</ol>
<p></p>
<h2><a name="Documentat">Developer Menu</a></h2>
<p>There are several on-line resources related to using libxml:</p>
<ol>
<li>Use the <a href="search.php">search engine</a>to look
upinformation.</li>
<li>Check the <a href="FAQ.html">FAQ.</a></li>
<li>Check the <a
href="http://xmlsoft.org/html/libxml-lib.html">extensivedocumentation</a>automatically
extracted from code comments.</li>
<li>Look at the documentation about <a
href="encoding.html">libxmlinternationalization support</a>.</li>
<li>This page provides a global overview and <a
href="example.html">someexamples</a>on how to use libxml.</li>
<li><a href="examples/index.html">Code examples</a></li>
<li>John Fleck's libxml2 tutorial: <a href="tutorial/index.html">html</a>or
<a href="tutorial/xmltutorial.pdf">pdf</a>.</li>
<li>If you need to parse large files, check the <a
href="xmlreader.html">xmlReader</a>API tutorial</li>
<li><a href="mailto:james@daa.com.au">James Henstridge</a>wrote <a
href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some
nicedocumentation</a>explaining how to use the libxml SAX interface.</li>
<li>George Lebl wrote <a
href="http://www-106.ibm.com/developerworks/library/l-gnome3/">an
articlefor IBM developerWorks</a>about using libxml.</li>
<li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the
TODOfile</a>.</li>
<li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>description.
If you are starting a new project using libxml you shouldreally use the
2.x version.</li>
<li>And don't forget to look at the <a
href="http://mail.gnome.org/archives/xml/">mailing-list archive</a>.</li>
</ol>
<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
<p>Well, bugs or missing features are always possible, and I will make apoint
of fixing them in a timely fashion. The best way to report a bug is touse the
<a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Gnomebug
tracking database</a>(make sure to use the "libxml2" module name). Ilook at
reports there regularly and it's good to have a reminder when a bugis still
open. Be sure to specify that the bug is for the package libxml2.</p>
<p>For small problems you can try to get help on IRC, the #xml channel
onirc.gnome.org (port 6667) usually have a few person subscribed which may
help(but there is no garantee and if a real issue is raised it should go on
themailing-list for archival).</p>
<p>There is also a mailing-list <a
href="mailto:xml@gnome.org">xml@gnome.org</a>for libxml, with an <a
href="http://mail.gnome.org/archives/xml/">on-line archive</a>(<a
href="http://xmlsoft.org/messages">old</a>). To subscribe to this list,please
visit the <a href="http://mail.gnome.org/mailman/listinfo/xml">associated
Web</a>page andfollow the instructions. <strong>Do not send code, I won't
debug it</strong>(but patches are really appreciated!).</p>
<p>Please note that with the current amount of virus and SPAM, sending mailto
the list without being subscribed won't work. There is *far too manybounces*
(in the order of a thousand a day !) I cannot approve them manuallyanymore.
If your mail to the list bounced waiting for administrator approval,it is
LOST ! Repost it and fix the problem triggering the error. Also pleasenote
that <span style="color: #FF0000; background-color: #FFFFFF">emails witha
legal warning asking to not copy or redistribute freely the informationsthey
contain</span>are <strong>NOT</strong>acceptable for the mailing-list,such
mail will as much as possible be discarded automatically, and are lesslikely
to be answered if they made it to the list, <strong>DO NOT</strong>post to
the list from an email address where such legal requirements areautomatically
added, get private paying support if you can't shareinformations.</p>
<p>Check the following <strong><span
style="color: #FF0000">beforeposting</span></strong>:</p>
<ul>
<li>Read the <a href="FAQ.html">FAQ</a>and <a href="search.php">use
thesearch engine</a>to get information related to your problem.</li>
<li>Make sure you are <a href="ftp://xmlsoft.org/libxml2/">using a
recentversion</a>, and that the problem still shows up in a recent
version.</li>
<li>Check the <a
href="http://mail.gnome.org/archives/xml/">listarchives</a>to see if the
problem was reported already. In this casethere is probably a fix
available, similarly check the <a
href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">registeredopen
bugs</a>.</li>
<li>Make sure you can reproduce the bug with xmllint or one of the
testprograms found in source in the distribution.</li>
<li>Please send the command showing the error as well as the input (as
anattachment)</li>
</ul>
<p>Then send the bug with associated information to reproduce it to the <a
href="mailto:xml@gnome.org">xml@gnome.org</a>list; if it's really
libxmlrelated I will approve it. Please do not send mail to me directly, it
makesthings really hard to track and in some cases I am not the best person
toanswer a given question, ask on the list.</p>
<p>To <span style="color: #E50000">be really clear about support</span>:</p>
<ul>
<li>Support or help <span style="color: #E50000">requests MUST be sent
tothe list or on bugzilla</span>in case of problems, so that the
Questionand Answers can be shared publicly. Failing to do so carries the
implicitmessage "I want free support but I don't want to share the
benefits withothers" and is not welcome. I will automatically Carbon-Copy
thexml@gnome.org mailing list for any technical reply made about libxml2
orlibxslt.</li>
<li>There is <span style="color: #E50000">no garantee of support</span>,
ifyour question remains unanswered after a week, repost it, making sure
yougave all the detail needed and the information requested.</li>
<li>Failing to provide information as requested or double checking firstfor
prior feedback also carries the implicit message "the time of thelibrary
maintainers is less valuable than my time" and might not bewelcome.</li>
</ul>
<p>Of course, bugs reported with a suggested patch for fixing them
willprobably be processed faster than those without.</p>
<p>If you're looking for help, a quick look at <a
href="http://mail.gnome.org/archives/xml/">the list archive</a>may
actuallyprovide the answer. I usually send source samples when answering
libxml2usage questions. The <a
href="http://xmlsoft.org/html/book1.html">auto-generated
documentation</a>isnot as polished as I would like (i need to learn more
about DocBook), butit's a good starting point.</p>
<h2><a name="help">How to help</a></h2>
<p>You can help the project in various ways, the best thing to do first is
tosubscribe to the mailing-list as explained before, check the <a
href="http://mail.gnome.org/archives/xml/">archives </a>and the <a
href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Gnome
bugdatabase</a>:</p>
<ol>
<li>Provide patches when you find problems.</li>
<li>Provide the diffs when you port libxml2 to a new platform. They may
notbe integrated in all cases but help pinpointing portability
problemsand</li>
<li>Provide documentation fixes (either as patches to the code comments
oras HTML diffs).</li>
<li>Provide new documentations pieces (translations, examples, etc...).</li>
<li>Check the TODO file and try to close one of the items.</li>
<li>Take one of the points raised in the archive or the bug database
andprovide a fix. <a href="mailto:daniel@veillard.com">Get in touch with
me</a>before to avoid synchronization problems and check that the
suggestedfix will fit in nicely :-)</li>
</ol>
<h2><a name="Downloads">Downloads</a></h2>
<p>The latest versions of libxml2 can be found on the <a
href="ftp://xmlsoft.org/libxml2/">xmlsoft.org</a>server ( <a
href="http://xmlsoft.org/sources/">HTTP</a>, <a
href="ftp://xmlsoft.org/libxml2/">FTP</a>and rsync are available), there is
alsomirrors (<a href="ftp://ftp.planetmirror.com/pub/xmlsoft/">Australia</a>(
<a href="http://xmlsoft.planetmirror.com/">Web</a>), <a
href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a
href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a>as <a
href="ftp://ftp.gnome.org/pub/GNOME/sources/libxml2/2.6/">source archive</a>,
Antonin Sprinzl also provide <a
href="ftp://gd.tuwien.ac.at/pub/libxml/">amirror in Austria</a>. (NOTE that
you need both the <a
href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a>and <a
href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>packages
installed to compile applications using libxml.)</p>
<p>You can find all the history of libxml(2) and libxslt releases in the <a
href="http://xmlsoft.org/sources/old/">old</a>directory. The
precompiledWindows binaries made by Igor Zlatovic are available in the <a
href="http://xmlsoft.org/sources/win32/">win32</a>directory.</p>
<p>Binary ports:</p>
<ul>
<li>Red Hat RPMs for i386 are available directly on <a
href="ftp://xmlsoft.org/libxml2/">xmlsoft.org</a>, the source RPM will
compile onany architecture supported by Red Hat.</li>
<li><a href="mailto:igor@zlatkovic.com">Igor Zlatkovic</a>is now
themaintainer of the Windows port, <a
href="http://www.zlatkovic.com/projects/libxml/index.html">he
providesbinaries</a>.</li>
<li>Blastwave provides <a
href="http://www.blastwave.org/packages.php/libxml2">Solarisbinaries</a>.</li>
<li><a href="mailto:Steve.Ball@explain.com.au">Steve Ball</a>provides <a
href="http://www.explain.com.au/oss/libxml2xslt.html">Mac Os
Xbinaries</a>.</li>
<li>The HP-UX porting center provides <a
href="http://hpux.connect.org.uk/hppd/hpux/Gnome/">HP-UX binaries</a></li>
<li>Bull provides precompiled <a
href="http://gnome.bullfreeware.com/new_index.html">RPMs for
AIX</a>aspatr of their GNOME packages</li>
</ul>
<p>If you know other supported binary ports, please <a
href="http://veillard.com/">contact me</a>.</p>
<p><a name="Snapshot">Snapshot:</a></p>
<ul>
<li>Code from the W3C cvs base libxml2 module, updated hourly <a
href="ftp://xmlsoft.org/libxml2/libxml2-cvs-snapshot.tar.gz">libxml2-cvs-snapshot.tar.gz</a>.</li>
<li>Docs, content of the web site, the list archive included <a
href="ftp://xmlsoft.org/libxml2/libxml-docs.tar.gz">libxml-docs.tar.gz</a>.</li>
</ul>
<p><a name="Contribs">Contributions:</a></p>
<p>I do accept external contributions, especially if compiling on
anotherplatform, get in touch with the list to upload the package, wrappers
forvarious languages have been provided, and can be found in the <a
href="python.html">bindings section</a></p>
<p>Libxml2 is also available from CVS:</p>
<ul>
<li><p>The <a href="http://cvs.gnome.org/viewcvs/libxml2/">Gnome
CVSbase</a>. Check the <a
href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a>page;
the CVS module is <b>libxml2</b>.</p>
</li>
<li>The <strong>libxslt</strong>module is also present there</li>
</ul>
<h2><a name="News">Releases</a></h2>
<p>Items not finished and worked on, get in touch with the list if you wantto
help those</p>
<ul>
<li>More testing on RelaxNG</li>
<li>Finishing up <a
href="http://www.w3.org/TR/xmlschema-1/">XMLSchemas</a></li>
</ul>
<p>The <a href="ChangeLog.html">change log</a>describes the recents commitsto
the <a href="http://cvs.gnome.org/viewcvs/libxml2/">CVS</a>code base.</p>
<p>There is the list of public releases:</p>
<h3>2.6.25: Jun 6 2006</h3>
<ul>
<li>portability fixes: Python detection (Joseph Sacco), compilation error
(William Brack and Graham Bennett), LynxOS patch (Olli Savia)</li>
<li>bug fixes: encoding buffer problem, mix of code and data in xmlIO.c
(Kjartan Maraas), entities in XSD validation (Kasimier Buchcik), various
XSD validation fixes (Kasimier), memory leak in pattern (Rob Richards and
Kasimier), attribute with colon in name (Rob Richards), XPath leak in
error reporting (Aleksey Sanin), XInclude text include of self
document.</li>
<li>improvements: Xpath optimizations (Kasimier), XPath object cache
(Kasimier), </li>
</ul>
<h3>2.6.24: Apr 28 2006</h3>
<ul>
<li>Portability fixes: configure on Windows, testapi compile on
windows(Kasimier Buchcik, venkat naidu), Borland C++ 6 compile (Eric
Zurcher),HP-UX compiler workaround (Rick Jones), xml2-config bugfix,
gcc-4.1cleanups, Python detection scheme (Joseph Sacco), UTF-8 file paths
onWindows (Roland Schwingel).</li>
<li>Improvements: xmlDOMWrapReconcileNamespaces xmlDOMWrapCloneNode
(KasimierBuchcik), XML catalog debugging (Rick Jones), update to Unicode
4.01.</li>
<li>Bug fixes: xmlParseChunk() problem in 2.6.23, xmlParseInNodeContext()on
HTML docs, URI behaviour on Windows (Rob Richards), comment streamingbug,
xmlParseComment (with William Brack), regexp bug fixes (DV &amp;Youri
Golovanov), xmlGetNodePath on text/CDATA (Kasimier),one Relax-NG
interleave bug, xmllint --path and --valid,XSD bugfixes (Kasimier),
remove debugleft in Python bindings (Nic Ferrier), xmlCatalogAdd bug
(Martin Cole),xmlSetProp fixes (Rob Richards), HTML IDness (Rob
Richards), a largenumber of cleanups and small fixes based on Coverity
reports, bugin character ranges, Unicode tables const (Aivars Kalvans),
schemasfix (Stefan Kost), xmlRelaxNGParse error
deallocation,xmlSchemaAddSchemaDoc error deallocation, error handling on
unallowedcode point, ixmllint --nonet to never reach the net (Gary
Coady),line break in writer after end PI (Jason Viers).</li>
<li>Documentation: man pages updates and cleanups (Daniel Leidert).</li>
<li>New features: Relax NG structure error handlers.</li>
</ul>
<h3>2.6.23: Jan 5 2006</h3>
<ul>
<li>portability fixes: Windows (Rob Richards), getaddrinfo on Windows(Kolja
Nowak, Rob Richards), icc warnings (Kjartan Maraas),--with-minimum
compilation fixes (William Brack), error case handling fixon Solaris
(Albert Chin), don't use 'list' as parameter name reported bySamuel Diaz
Garcia, more old Unices portability fixes (Albert Chin),MinGW compilation
(Mark Junker), HP-UX compiler warnings (RickJones),</li>
<li>code cleanup: xmlReportError (Adrian Mouat), remove
xmlBufferClose(Geert Jansen), unreachable code (Oleksandr Kononenko),
refactoringparsing code (Bjorn Reese)</li>
<li>bug fixes: xmlBuildRelativeURI and empty path (William
Brack),combinatory explosion and performances in regexp code, leak
inxmlTextReaderReadString(), xmlStringLenDecodeEntities problem
(MassimoMorara), Identity Constraints bugs and a segfault (Kasimier
Buchcik),XPath pattern based evaluation bugs (DV &amp;
Kasimier),xmlSchemaContentModelDump() memory leak (Kasimier), potential
leak inxmlSchemaCheckCSelectorXPath(), xmlTextWriterVSprintf() misuse
ofvsnprintf (William Brack), XHTML serialization fix (Rob Richards),
CRLFsplit problem (William), issues with non-namespaced attributes
inxmlAddChild() xmlAddNextSibling() and xmlAddPrevSibling() (Rob
Richards),HTML parsing of script, Python must not output to stdout (Nic
Ferrier),exclusive C14N namespace visibility (Aleksey Sanin), XSD
dataypetotalDigits bug (Kasimier Buchcik), error handling when writing to
anxmlBuffer (Rob Richards), runtest schemas error not reported
(HisashiFujinaka), signed/unsigned problem in date/time code (Albert
Chin), fixXSI driven XSD validation (Kasimier), parsing of xs:decimal
(Kasimier),fix DTD writer output (Rob Richards), leak in
xmlTextReaderReadInnerXml(Gary Coady), regexp bug affecting schemas
(Kasimier), configuration ofruntime debugging (Kasimier),
xmlNodeBufGetContent bug on entity refs(Oleksandr Kononenko),
xmlRegExecPushString2 bug (Sreeni Nair),compilation and build fixes
(Michael Day), removed dependancies onxmlSchemaValidError (Kasimier), bug
with &lt;xml:foo/&gt;, more XPathpattern based evaluation fixes
(Kasimier)</li>
<li>improvements: XSD Schemas redefinitions/restrictions (KasimierBuchcik),
node copy checks and fix for attribute (Rob Richards), countedtransition
bug in regexps, ctxt-&gt;standalone = -2 to indicate nostandalone
attribute was found, add xmlSchemaSetParserStructuredErrors()(Kasimier
Buchcik), add xmlTextReaderSchemaValidateCtxt() to API(Kasimier), handle
gzipped HTTP resources (Gary Coady), addhtmlDocDumpMemoryFormat. (Rob
Richards),</li>
<li>documentation: typo (Michael Day), libxml man page (Albert Chin),
savefunction to XML buffer (Geert Jansen), small doc fix (Aron
Stansvik),</li>
</ul>
<h3>2.6.22: Sep 12 2005</h3>
<ul>
<li>build fixes: compile without schematron (Stéphane Bidoul)</li>
<li>bug fixes: xmlDebugDumpNode on namespace node (Oleg Paraschenko)i,CDATA
push parser bug, xmlElemDump problem with XHTML1 doc,XML_FEATURE_xxx
clash with expat headers renamed XML_WITH_xxx, fix someoutput formatting
for meta element (Rob Richards), script and styleXHTML1 serialization
(David Madore), Attribute derivation fixups in XSD(Kasimier Buchcik),
better IDC error reports (Kasimier Buchcik)</li>
<li>improvements: add XML_SAVE_NO_EMPTY xmlSaveOption (Rob Richards),
addXML_SAVE_NO_XHTML xmlSaveOption, XML Schemas improvements preparing
forderive (Kasimier Buchcik).</li>
<li>documentation: generation of gtk-doc like docs, integration
withdevhelp.</li>
</ul>
<h3>2.6.21: Sep 4 2005</h3>
<ul>
<li>build fixes: Cygwin portability fixes (Gerrit P. Haase),
callingconvention problems on Windows (Marcus Boerger), cleanups based on
Linus'sparse tool, update of win32/configure.js (Rob Richards), remove
warningson Windows(Marcus Boerger), compilation without SAX1, detection
of thePython binary, use $GCC inestad of $CC = 'gcc' (Andrew W.
Nosenko),compilation/link with threads and old gcc, compile problem by
C370 onZ/OS,</li>
<li>bug fixes: http_proxy environments (Peter Breitenlohner), HTML UTF-8bug
(Jiri Netolicky), XPath NaN compare bug (William Brack),htmlParseScript
potential bug, Schemas regexp handling of spaces, Base64Schemas
comparisons NIST passes, automata build error xsd:all,xmlGetNodePath for
namespaced attributes (Alexander Pohoyda), xmlSchemasforeign namespaces
handling, XML Schemas facet comparison (KupriyanovAnatolij),
xmlSchemaPSimpleTypeErr error report (Kasimier Buchcik), xml:namespace
ahndling in Schemas (Kasimier), empty model group in Schemas(Kasimier),
wilcard in Schemas (Kasimier), URI composition (William),xs:anyType in
Schemas (Kasimier), Python resolver emmitting errormessages directly,
Python xmlAttr.parent (Jakub Piotr Clapa), trying tofix the file path/URI
conversion, xmlTextReaderGetAttribute fix (RobRichards),
xmlSchemaFreeAnnot memleak (Kasimier), HTML UTF-8serialization, streaming
XPath, Schemas determinism detection problem,XInclude bug, Schemas
context type (Dean Hill), validation fix (DerekPoon),
xmlTextReaderGetAttribute[Ns] namespaces (Rob Richards), Schemastype fix
(Kuba Nowakowski), UTF-8 parser bug, error in encoding
handling,xmlGetLineNo fixes, bug on entities handling, entity name
extraction inerror handling with XInclude, text nodes in HTML body tags
(Gary Coady),xml:id and IDness at the treee level fixes, XPath streaming
patternsbugs.</li>
<li>improvements: structured interfaces for schemas and RNG error
reports(Marcus Boerger), optimization of the char data inner loop
parsing(thanks to Behdad Esfahbod for the idea), schematron validation
thoughnot finished yet, xmlSaveOption to omit XML declaration, keyref
matcherror reports (Kasimier), formal expression handling code not
pluggedyet, more lax mode for the HTML parser, parser XML_PARSE_COMPACT
optionfor text nodes allocation.</li>
<li>documentation: xmllint man page had --nonet duplicated</li>
</ul>
<h3>2.6.20: Jul 10 2005</h3>
<ul>
<li>build fixes: Windows build (Rob Richards), Mingw compilation
(IgorZlatkovic), Windows Makefile (Igor), gcc warnings (Kasimier
andandriy@google.com), use gcc weak references to pthread to avoid
thepthread dependancy on Linux, compilation problem (Steve Nairn),
compilingof subset (Morten Welinder), IPv6/ss_family compilation (William
Brack),compilation when disabling parts of the library, standalone
testdistribution.</li>
<li>bug fixes: bug in lang(), memory cleanup on errors (William Brack),HTTP
query strings (Aron Stansvik), memory leak in DTD (William),
integeroverflow in XPath (William), nanoftp buffer size, pattern "." apth
fixup(Kasimier), leak in tree reported by Malcolm Rowe, replaceNode
patch(Brent Hendricks), CDATA with NULL content (Mark Vakoc), xml:base
fixupon XInclude (William), pattern fixes (William), attribute bug
inexclusive c14n (Aleksey Sanin), xml:space and xml:lang with SAX2
(RobRichards), namespace trouble in complex parsing (Malcolm Rowe), XSD
typeQNames fixes (Kasimier), XPath streaming fixups (William), RelaxNG
bug(Rob Richards), Schemas for Schemas fixes (Kasimier), removal of ID
(RobRichards), a small RelaxNG leak, HTML parsing in push mode bug
(JamesBursa), failure to detect UTF-8 parsing bugs in CDATA
sections,areBlanks() heuristic failure, duplicate attributes in DTD
bug(William).</li>
<li>improvements: lot of work on Schemas by Kasimier Buchcik both
onconformance and streaming, Schemas validation messages (Kasimier
Buchcik,Matthew Burgess), namespace removal at the python level
(BrentHendricks), Update to new Schemas regression tests from
W3C/Nist(Kasimier), xmlSchemaValidateFile() (Kasimier), implementation
ofxmlTextReaderReadInnerXml and xmlTextReaderReadOuterXml (James
Wert),standalone test framework and programs, new DOM import
APIsxmlDOMWrapReconcileNamespaces() xmlDOMWrapAdoptNode()
andxmlDOMWrapRemoveNode(), extension of xmllint capabilities for SAX
andSchemas regression tests, xmlStopParser() available in pull mode
too,ienhancement to xmllint --shell namespaces support, Windows port of
thestandalone testing tools (Kasimier and
William),xmlSchemaValidateStream() xmlSchemaSAXPlug() and
xmlSchemaSAXUnplug() SAXSchemas APIs, Schemas xmlReader support.</li>
</ul>
<h3>2.6.19: Apr 02 2005</h3>
<ul>
<li>build fixes: drop .la from RPMs, --with-minimum build fix
(WilliamBrack), use XML_SOCKLEN_T instead of SOCKLEN_T because it breaks
with AIX5.3 compiler, fixed elfgcchack.h generation and PLT reduction
code onLinux/ELF/gcc4</li>
<li>bug fixes: schemas type decimal fixups (William Brack), xmmlint
returncode (Gerry Murphy), small schemas fixes (Matthew Burgess and
GUYFabrice), workaround "DAV:" namespace brokeness in c14n (Aleksey
Sanin),segfault in Schemas (Kasimier Buchcik), Schemas attribute
validation(Kasimier), Prop related functions and xmlNewNodeEatName (Rob
Richards),HTML serialization of name attribute on a elements, Python
error handlersleaks and improvement (Brent Hendricks), uninitialized
variable inencoding code, Relax-NG validation bug, potential crash
ifgnorableWhitespace is NULL, xmlSAXParseDoc and xmlParseDoc
signatures,switched back to assuming UTF-8 in case no encoding is given
atserialization time</li>
<li>improvements: lot of work on Schemas by Kasimier Buchcik on
facetschecking and also mixed handling.</li>
<li></li>
</ul>
<h3>2.6.18: Mar 13 2005</h3>
<ul>
<li>build fixes: warnings (Peter Breitenlohner), testapi.c
generation,Bakefile support (Francesco Montorsi), Windows compilation
(Joel Reed),some gcc4 fixes, HP-UX portability fixes (Rick Jones).</li>
<li>bug fixes: xmlSchemaElementDump namespace (Kasimier Buchcik), push
andxmlreader stopping on non-fatal errors, thread support for
dictionnariesreference counting (Gary Coady), internal subset and push
problem, URLsaved in xmlCopyDoc, various schemas bug fixes (Kasimier),
Python pathsfixup (Stephane Bidoul), xmlGetNodePath and namespaces,
xmlSetNsProp fix(Mike Hommey), warning should not count as error (William
Brack),xmlCreatePushParser empty chunk, XInclude parser flags (William),
cleanupFTP and HTTP code to reuse the uri parsing and IPv6
(William),xmlTextWriterStartAttributeNS fix (Rob Richards),
XMLLINT_INDENT beingempty (William), xmlWriter bugs (Rob Richards),
multithreading on Windows(Rich Salz), xmlSearchNsByHref fix (Kasimier),
Python binding leak (BrentHendricks), aliasing bug exposed by gcc4 on
s390, xmlTextReaderNext bug(Rob Richards), Schemas decimal type fixes
(William Brack),xmlByteConsumed static buffer (Ben Maurer).</li>
<li>improvement: speedup parsing comments and DTDs, dictionnary support
forhash tables, Schemas Identity constraints (Kasimier), streaming
XPathsubset, xmlTextReaderReadString added (Bjorn Reese), Schemas
canonicalvalues handling (Kasimier), add xmlTextReaderByteConsumed
(AronStansvik),</li>
<li>Documentation: Wiki support (Joel Reed)</li>
</ul>
<h3>2.6.17: Jan 16 2005</h3>
<ul>
<li>build fixes: Windows, warnings removal (William Brack),maintainer-clean
dependency(William), build in a different directory(William), fixing
--with-minimum configure build (William), BeOS build(Marcin Konicki),
Python-2.4 detection (William), compilation on AIX (DanMcNichol)</li>
<li>bug fixes: xmlTextReaderHasAttributes (Rob Richards),
xmlCtxtReadFile()to use the catalog(s), loop on output (William Brack),
XPath memory leak,ID deallocation problem (Steve Shepard), debugDumpNode
crash (William),warning not using error callback (William), xmlStopParser
bug (William),UTF-16 with BOM on DTDs (William), namespace bug on empty
elements inpush mode (Rob Richards), line and col computations fixups
(AlekseySanin), xmlURIEscape fix (William), xmlXPathErr on bad range
(William),patterns with too many steps, bug in RNG choice optimization,
line numbersometimes missing.</li>
<li>improvements: XSD Schemas (Kasimier Buchcik), python
generator(William), xmlUTF8Strpos speedup (William), unicode Python
strings(William), XSD error reports (Kasimier Buchcik), Python __str__
callserialize().</li>
<li>new APIs: added xmlDictExists(), GetLineNumber and GetColumnNumber
forthe xmlReader (Aleksey Sanin), Dynamic Shared Libraries APIs (mostly
JoelReed), error extraction API from regexps, new XMLSave option for
format(Phil Shafer)</li>
<li>documentation: site improvement (John Fleck), FAQ entries(William).</li>
</ul>
<h3>2.6.16: Nov 10 2004</h3>
<ul>
<li>general hardening and bug fixing crossing all the API based on
newautomated regression testing</li>
<li>build fix: IPv6 build and test on AIX (Dodji Seketeli)</li>
<li>bug fixes: problem with XML::Libxml reported by Petr Pajas,
encodingconversion functions return values, UTF-8 bug affecting XPath
reported byMarkus Bertheau, catalog problem with NULL entries (William
Brack)</li>
<li>documentation: fix to xmllint man page, some API function
descritpionwere updated.</li>
<li>improvements: DTD validation APIs provided at the Python level
(BrentHendricks)</li>
</ul>
<h3>2.6.15: Oct 27 2004</h3>
<ul>
<li>security fixes on the nanoftp and nanohttp modules</li>
<li>build fixes: xmllint detection bug in configure, building outside
thesource tree (Thomas Fitzsimmons)</li>
<li>bug fixes: HTML parser on broken ASCII chars in names (William),
Pythonpaths (Malcolm Tredinnick), xmlHasNsProp and default namespace
(William),saving to python file objects (Malcolm Tredinnick), DTD lookup
fix(Malcolm), save back &lt;group&gt; in catalogs (William), tree
buildfixes (DV and Rob Richards), Schemas memory bug, structured error
handleron Python 64bits, thread local memory deallocation, memory leak
reportedby Volker Roth, xmlValidateDtd in the presence of an internal
subset,entities and _private problem (William), xmlBuildRelativeURI
error(William).</li>
<li>improvements: better XInclude error reports (William), tree
debuggingmodule and tests, convenience functions at the Reader API
(GrahamBennett), add support for PI in the HTML parser.</li>
</ul>
<h3>2.6.14: Sep 29 2004</h3>
<ul>
<li>build fixes: configure paths for xmllint and xsltproc,
compilationwithout HTML parser, compilation warning cleanups (William
Brack &amp;Malcolm Tredinnick), VMS makefile update (Craig Berry),</li>
<li>bug fixes: xmlGetUTF8Char (William Brack), QName properties
(KasimierBuchcik), XInclude testing, Notation serialization,
UTF8ToISO8859xtranscoding (Mark Itzcovitz), lots of XML Schemas cleanup
and fixes(Kasimier), ChangeLog cleanup (Stepan Kasal), memory fixes (Mark
Vakoc),handling of failed realloc(), out of bound array adressing in
Schemasdate handling, Python space/tabs cleanups (Malcolm Tredinnick),
NMTOKENSE20 validation fix (Malcolm),</li>
<li>improvements: added W3C XML Schemas testsuite (Kasimier Buchcik),
addxmlSchemaValidateOneElement (Kasimier), Python exception
hierearchy(Malcolm Tredinnick), Python libxml2 driver improvement
(MalcolmTredinnick), Schemas support for
xsi:schemaLocation,xsi:noNamespaceSchemaLocation, xsi:type (Kasimier
Buchcik)</li>
</ul>
<h3>2.6.13: Aug 31 2004</h3>
<ul>
<li>build fixes: Windows and zlib (Igor Zlatkovic), -O flag with
gcc,Solaris compiler warning, fixing RPM BuildRequires,</li>
<li>fixes: DTD loading on Windows (Igor), Schemas error reports
APIs(Kasimier Buchcik), Schemas validation crash, xmlCheckUTF8 (William
Brackand Julius Mittenzwei), Schemas facet check (Kasimier), default
namespaceproblem (William), Schemas hexbinary empty values, encoding
error couldgenrate a serialization loop.</li>
<li>Improvements: Schemas validity improvements (Kasimier), added --pathand
--load-trace options to xmllint</li>
<li>documentation: tutorial update (John Fleck)</li>
</ul>
<h3>2.6.12: Aug 22 2004</h3>
<ul>
<li>build fixes: fix --with-minimum, elfgcchack.h fixes
(PeterBreitenlohner), perl path lookup (William), diff on Solaris
(AlbertChin), some 64bits cleanups.</li>
<li>Python: avoid a warning with 2.3 (William Brack), tab and space
mixes(William), wrapper generator fixes (William), Cygwin support (Gerrit
P.Haase), node wrapper fix (Marc-Antoine Parent), XML Schemas
support(Torkel Lyng)</li>
<li>Schemas: a lot of bug fixes and improvements from Kasimier Buchcik</li>
<li>fixes: RVT fixes (William), XPath context resets bug (William),
memorydebug (Steve Hay), catalog white space handling (Peter
Breitenlohner),xmlReader state after attribute reading (William),
structured errorhandler (William), XInclude generated xml:base fixup
(William), Windowsmemory reallocation problem (Steve Hay), Out of Memory
conditionshandling (William and Olivier Andrieu), htmlNewDoc() charset
bug,htmlReadMemory init (William), a posteriori validation DTD
base(William), notations serialization missing, xmlGetNodePath
(Dodji),xmlCheckUTF8 (Diego Tartara), missing line numbers on
entity(William)</li>
<li>improvements: DocBook catalog build scrip (William), xmlcatalog
tool(Albert Chin), xmllint --c14n option, no_proxy environment (Mike
Hommey),xmlParseInNodeContext() addition, extend xmllint --shell, allow
XIncludeto not generate start/end nodes, extend xmllint --version to
include CVStag (William)</li>
<li>documentation: web pages fixes, validity API docs fixes
(William)schemas API fix (Eric Haszlakiewicz), xmllint man page (John
Fleck)</li>
</ul>
<h3>2.6.11: July 5 2004</h3>
<ul>
<li>Schemas: a lot of changes and improvements by Kasimier Buchcik
forattributes, namespaces and simple types.</li>
<li>build fixes: --with-minimum (William Brack), some gcc
cleanup(William), --with-thread-alloc (William)</li>
<li>portability: Windows binary package change (Igor Zlatkovic),
Catalogpath on Windows</li>
<li>documentation: update to the tutorial (John Fleck), xmllint return
code(John Fleck), man pages (Ville Skytta),</li>
<li>bug fixes: C14N bug serializing namespaces (Aleksey Sanin),
testSAXproperly initialize the library (William), empty node set in
XPath(William), xmlSchemas errors (William), invalid charref problem
pointedby Morus Walter, XInclude xml:base generation (William), Relax-NG
bugwith div processing (William), XPointer and xml:base
problem(William),Reader and entities, xmllint return code for schemas
(William), readerstreaming problem (Steve Ball), DTD serialization
problem (William),libxml.m4 fixes (Mike Hommey), do not provide
destructors as methods onPython classes, xmlReader buffer bug, Python
bindings memory interfacesimprovement (with Stéphane Bidoul), Fixed the
push parser to be back tosynchronous behaviour.</li>
<li>improvement: custom per-thread I/O enhancement (Rob Richards),
registernamespace in debug shell (Stefano Debenedetti), Python based
regressiontest for non-Unix users (William), dynamically increase the
number ofXPath extension functions in Python and fix a memory leak
(Marc-AntoineParent and William)</li>
<li>performance: hack done with Arjan van de Ven to reduce ELF footprintand
generated code on Linux, plus use gcc runtime profiling to optimizethe
code generated in the RPM packages.</li>
</ul>
<h3>2.6.10: May 17 2004</h3>
<ul>
<li>Web page generated for ChangeLog</li>
<li>build fixes: --without-html problems, make check without make all</li>
<li>portability: problem with xpath.c on Windows (MSC and Borland),
memcmpvs. strncmp on Solaris, XPath tests on Windows (Mark Vakoc), C++ do
notuse "list" as parameter name, make tests work with Python 1.5
(EdDavis),</li>
<li>improvements: made xmlTextReaderMode public, small buffers
resizing(Morten Welinder), add --maxmem option to xmllint,
addxmlPopInputCallback() for Matt Sergeant, refactoring of
serializationescaping, added escaping customization</li>
<li>bugfixes: xsd:extension (Taihei Goi), assorted regexp bugs
(WilliamBrack), xmlReader end of stream problem, node deregistration with
reader,URI escaping and filemanes, XHTML1 formatting (Nick Wellnhofer),
regexptransition reduction (William), various XSD Schemas fixes
(KasimierBuchcik), XInclude fallback problem (William), weird problems
with DTD(William), structured error handler callback context (William),
reversexmlEncodeSpecialChars() behaviour back to escaping '"'</li>
</ul>
<h3>2.6.9: Apr 18 2004</h3>
<ul>
<li>implement xml:id Working Draft, relaxed XPath id() checking</li>
<li>bugfixes: xmlCtxtReset (Brent Hendricks), line number and CDATA
(DaveBeckett), Relax-NG compilation (William Brack), Regexp patches
(withWilliam), xmlUriEscape (Mark Vakoc), a Relax-NG notAllowed problem
(withWilliam), Relax-NG name classes compares (William), XInclude
duplicatefallback (William), external DTD encoding detection (William), a
DTDvalidation bug (William), xmlReader Close() fix, recusive
extentionschemas</li>
<li>improvements: use xmlRead* APIs in test tools (Mark Vakoc),
indentingsave optimization, better handle IIS broken HTTP redirect
behaviour (IanHummel), HTML parser frameset (James Bursa), libxml2-python
RPMdependancy, XML Schemas union support (Kasimier Buchcik), warning
removalclanup (William), keep ChangeLog compressed when installing from
RPMs</li>
<li>documentation: examples and xmlDocDumpMemory docs (John Fleck),
newexample (load, xpath, modify, save), xmlCatalogDump() comments,</li>
<li>Windows: Borland C++ builder (Eric Zurcher), work around
Microsoftcompiler NaN handling bug (Mark Vakoc)</li>
</ul>
<h3>2.6.8: Mar 23 2004</h3>
<ul>
<li>First step of the cleanup of the serialization code and APIs</li>
<li>XML Schemas: mixed content (Adam Dickmeiss), QName handling fixes
(AdamDickmeiss), anyURI for "" (John Belmonte)</li>
<li>Python: Canonicalization C14N support added (Anthony Carrico)</li>
<li>xmlDocCopyNode() extension (William)</li>
<li>Relax-NG: fix when processing XInclude results (William),
externalreference in interleave (William), missing error on
&lt;choice&gt;failure (William), memory leak in schemas datatype
facets.</li>
<li>xmlWriter: patch for better DTD support (Alfred Mickautsch)</li>
<li>bug fixes: xmlXPathLangFunction memory leak (Mike Hommey and
WilliamBrack), no ID errors if using HTML_PARSE_NOERROR, xmlcatalog
fallbacks toURI on SYSTEM lookup failure, XInclude parse flags
inheritance (William),XInclude and XPointer fixes for entities (William),
XML parser bugreported by Holger Rauch, nanohttp fd leak (William),
regexps chargroups '-' handling (William), dictionnary reference counting
problems,do not close stderr.</li>
<li>performance patches from Petr Pajas</li>
<li>Documentation fixes: XML_CATALOG_FILES in man pages (Mike Hommey)</li>
<li>compilation and portability fixes: --without-valid, catalog
cleanups(Peter Breitenlohner), MingW patch (Roland Schwingel),
cross-compilationto Windows (Christophe de Vienne), --with-html-dir
fixup (Julio MerinoVidal), Windows build (Eric Zurcher)</li>
</ul>
<h3>2.6.7: Feb 23 2004</h3>
<ul>
<li>documentation: tutorial updates (John Fleck), benchmark results</li>
<li>xmlWriter: updates and fixes (Alfred Mickautsch, Lucas Brasilino)</li>
<li>XPath optimization (Petr Pajas)</li>
<li>DTD ID handling optimization</li>
<li>bugfixes: xpath number with &gt; 19 fractional (William Brack),
pushmode with unescaped '&gt;' characters, fix xmllint --stream --timing,
fixxmllint --memory --stream memory usage,
xmlAttrSerializeTxtContenthandling NULL, trying to fix Relax-NG/Perl
interface.</li>
<li>python: 2.3 compatibility, whitespace fixes (Malcolm Tredinnick)</li>
<li>Added relaxng option to xmllint --shell</li>
</ul>
<h3>2.6.6: Feb 12 2004</h3>
<ul>
<li>nanohttp and nanoftp: buffer overflow error on URI parsing (Igor
andWilliam) reported by Yuuichi Teranishi</li>
<li>bugfixes: make test and path issues, xmlWriter attribute
serialization(William Brack), xmlWriter indentation (William), schemas
validation(Eric Haszlakiewicz), XInclude dictionnaries issues (William
and OlegParaschenko), XInclude empty fallback (William), HTML warnings
(William),XPointer in XInclude (William), Python namespace
serialization,isolat1ToUTF8 bound error (Alfred Mickautsch), output of
parameterentities in internal subset (William), internal subset bug in
push mode,&lt;xs:all&gt; fix (Alexey Sarytchev)</li>
<li>Build: fix for automake-1.8 (Alexander Winston), warnings
removal(Philip Ludlam), SOCKLEN_T detection fixes (Daniel Richard),
fix--with-minimum configuration.</li>
<li>XInclude: allow the 2001 namespace without warning.</li>
<li>Documentation: missing example/index.html (John Fleck),
versiondependancies (John Fleck)</li>
<li>reader API: structured error reporting (Steve Ball)</li>
<li>Windows compilation: mingw, msys (Mikhail Grushinskiy),
functionprototype (Cameron Johnson), MSVC6 compiler warnings,
_WINSOCKAPI_patch</li>
<li>Parsers: added xmlByteConsumed(ctxt) API to get the byte offest
ininput.</li>
</ul>
<h3>2.6.5: Jan 25 2004</h3>
<ul>
<li>Bugfixes: dictionnaries for schemas (William Brack), regexp
segfault(William), xs:all problem (William), a number of XPointer
bugfixes(William), xmllint error go to stderr, DTD validation problem
withnamespace, memory leak (William), SAX1 cleanup and minimal options
fixes(Mark Vadoc), parser context reset on error (Shaun McCance), XPath
unionevaluation problem (William) , xmlReallocLoc with NULL (Aleksey
Sanin),XML Schemas double free (Steve Ball), XInclude with no href,
argumentcallbacks order for XPath callbacks (Frederic Peters)</li>
<li>Documentation: python scripts (William Brack), xslt stylesheets
(JohnFleck), doc (Sven Zimmerman), I/O example.</li>
<li>Python bindings: fixes (William), enum support (Stéphane
Bidoul),structured error reporting (Stéphane Bidoul)</li>
<li>XInclude: various fixes for conformance, problem related to
dictionnaryreferences (William &amp; me), recursion (William)</li>
<li>xmlWriter: indentation (Lucas Brasilino), memory leaks
(AlfredMickautsch),</li>
<li>xmlSchemas: normalizedString datatype (John Belmonte)</li>
<li>code cleanup for strings functions (William)</li>
<li>Windows: compiler patches (Mark Vakoc)</li>
<li>Parser optimizations, a few new XPath and dictionnary APIs for
futureXSLT optimizations.</li>
</ul>
<h3>2.6.4: Dec 24 2003</h3>
<ul>
<li>Windows build fixes (Igor Zlatkovic)</li>
<li>Some serious XInclude problems reported by Oleg Paraschenko and</li>
<li>Unix and Makefile packaging fixes (me, William Brack,</li>
<li>Documentation improvements (John Fleck, William Brack), example
fix(Lucas Brasilino)</li>
<li>bugfixes: xmlTextReaderExpand() with xmlReaderWalker, XPath handling
ofNULL strings (William Brack) , API building reader or parser
fromfiledescriptor should not close it, changed XPath sorting to be
stableagain (William Brack), xmlGetNodePath() generating '(null)'
(WilliamBrack), DTD validation and namespace bug (William Brack), XML
Schemasdouble inclusion behaviour</li>
</ul>
<h3>2.6.3: Dec 10 2003</h3>
<ul>
<li>documentation updates and cleanup (DV, William Brack, John Fleck)</li>
<li>added a repository of examples, examples from Aleksey Sanin,
DodjiSeketeli, Alfred Mickautsch</li>
<li>Windows updates: Mark Vakoc, Igor Zlatkovic, Eric Zurcher,
Mingw(Kenneth Haley)</li>
<li>Unicode range checking (William Brack)</li>
<li>code cleanup (William Brack)</li>
<li>Python bindings: doc (John Fleck), bug fixes</li>
<li>UTF-16 cleanup and BOM issues (William Brack)</li>
<li>bug fixes: ID and xmlReader validation, XPath (William Brack),xmlWriter
(Alfred Mickautsch), hash.h inclusion problem, HTML parser(James Bursa),
attribute defaulting and validation, some serializationcleanups,
XML_GET_LINE macro, memory debug when using threads (WilliamBrack),
serialization of attributes and entities content, xmlWriter(Daniel
Schulman)</li>
<li>XInclude bugfix, new APIs and update to the last version including
thenamespace change.</li>
<li>XML Schemas improvements: include (Robert Stepanek), import
andnamespace handling, fixed the regression tests troubles, added
examplesbased on Eric van der Vlist book, regexp fixes</li>
<li>preliminary pattern support for streaming (needed for
schemasconstraints), added xmlTextReaderPreservePattern() to collect
subdocumentwhen streaming.</li>
<li>various fixes in the structured error handling</li>
</ul>
<h3>2.6.2: Nov 4 2003</h3>
<ul>
<li>XPath context unregistration fixes</li>
<li>text node coalescing fixes (Mark Lilback)</li>
<li>API to screate a W3C Schemas from an existing document (Steve Ball)</li>
<li>BeOS patches (Marcin 'Shard' Konicki)</li>
<li>xmlStrVPrintf function added (Aleksey Sanin)</li>
<li>compilation fixes (Mark Vakoc)</li>
<li>stdin parsing fix (William Brack)</li>
<li>a posteriori DTD validation fixes</li>
<li>xmlReader bug fixes: Walker fixes, python bindings</li>
<li>fixed xmlStopParser() to really stop the parser and errors</li>
<li>always generate line numbers when using the new xmlReadxxxfunctions</li>
<li>added XInclude support to the xmlReader interface</li>
<li>implemented XML_PARSE_NONET parser option</li>
<li>DocBook XSLT processing bug fixed</li>
<li>HTML serialization for &lt;p&gt; elements (William Brack and me)</li>
<li>XPointer failure in XInclude are now handled as resource errors</li>
<li>fixed xmllint --html to use the HTML serializer on output
(added--xmlout to implement the previous behaviour of saving it using the
XMLserializer)</li>
</ul>
<h3>2.6.1: Oct 28 2003</h3>
<ul>
<li>Mostly bugfixes after the big 2.6.0 changes</li>
<li>Unix compilation patches: libxml.m4 (Patrick Welche), warnings
cleanup(William Brack)</li>
<li>Windows compilation patches (Joachim Bauch, Stephane Bidoul,
IgorZlatkovic)</li>
<li>xmlWriter bugfix (Alfred Mickautsch)</li>
<li>chvalid.[ch]: couple of fixes from Stephane Bidoul</li>
<li>context reset: error state reset, push parser reset (GrahamBennett)</li>
<li>context reuse: generate errors if file is not readable</li>
<li>defaulted attributes for element coming from internal entities(Stephane
Bidoul)</li>
<li>Python: tab and spaces mix (William Brack)</li>
<li>Error handler could crash in DTD validation in 2.6.0</li>
<li>xmlReader: do not use the document or element _private field</li>
<li>testSAX.c: avoid a problem with some PIs (Massimo Morara)</li>
<li>general bug fixes: mandatory encoding in text decl, serializingDocument
Fragment nodes, xmlSearchNs 2.6.0 problem (Kasimier Buchcik),XPath errors
not reported, slow HTML parsing of large documents.</li>
</ul>
<h3>2.6.0: Oct 20 2003</h3>
<ul>
<li>Major revision release: should be API and ABI compatible but got a
lotof change</li>
<li>Increased the library modularity, far more options can be stripped
out,a --with-minimum configuration will weight around 160KBytes</li>
<li>Use per parser and per document dictionnary, allocate names and
smalltext nodes from the dictionnary</li>
<li>Switch to a SAX2 like parser rewrote most of the XML parser
core,provides namespace resolution and defaulted attributes, minimize
memoryallocations and copies, namespace checking and specific error
handling,immutable buffers, make predefined entities static structures,
etc...</li>
<li>rewrote all the error handling in the library, all errors can
beintercepted at a structured level, with precise
informationavailable.</li>
<li>New simpler and more generic XML and HTML parser APIs, allowing
toeasilly modify the parsing options and reuse parser context for
multipleconsecutive documents.</li>
<li>Similar new APIs for the xmlReader, for options and reuse, provided
newfunctions to access content as const strings, use them for
Pythonbindings</li>
<li>a lot of other smaller API improvements: xmlStrPrintf (Aleksey
Sanin),Walker i.e. reader on a document tree based on Alfred Mickautsch
code,make room in nodes for line numbers, reference counting and future
PSVIextensions, generation of character ranges to be checked with
fasteralgorithm (William), xmlParserMaxDepth (Crutcher Dunnavant),
bufferaccess</li>
<li>New xmlWriter API provided by Alfred Mickautsch</li>
<li>Schemas: base64 support by Anthony Carrico</li>
<li>Parser&lt;-&gt;HTTP integration fix, proper processing of the
Mime-Typeand charset informations if available.</li>
<li>Relax-NG: bug fixes including the one reported by Martijn Faassen
andzeroOrMore, better error reporting.</li>
<li>Python bindings (Stéphane Bidoul), never use stdout for
errorsoutput</li>
<li>Portability: all the headers have macros for export and
callingconvention definitions (Igor Zlatkovic), VMS update (Craig A.
Berry),Windows: threads (Jesse Pelton), Borland compiler (Eric Zurcher,
Igor),Mingw (Igor), typos (Mark Vakoc), beta version (Stephane
Bidoul),warning cleanups on AIX and MIPS compilers (William Brack), BeOS
(Marcin'Shard' Konicki)</li>
<li>Documentation fixes and README (William Brack), search fix
(William),tutorial updates (John Fleck), namespace docs (Stefan Kost)</li>
<li>Bug fixes: xmlCleanupParser (Dave Beckett), threading
uninitializedmutexes, HTML doctype lowercase, SAX/IO (William),
compression detectionand restore (William), attribute declaration in DTDs
(William), namespaceon attribute in HTML output (William), input filename
(Rob Richards),namespace DTD validation, xmlReplaceNode (Chris Ryland),
I/O callbacks(Markus Keim), CDATA serialization (Shaun McCance),
xmlReader (PeterDerr), high codepoint charref like &amp;#x10FFFF;, buffer
access in pushmode (Justin Fletcher), TLS threads on Windows (Jesse
Pelton), XPath bug(William), xmlCleanupParser (Marc Liyanage), CDATA
output (William), HTTPerror handling.</li>
<li>xmllint options: --dtdvalidfpi for Tobias Reif, --sax1 for
compattesting, --nodict for building without tree dictionnary, --nocdata
toreplace CDATA by text, --nsclean to remove surperfluous
namespacedeclarations</li>
<li>added xml2-config --libtool-libs option from Kevin P. Fleming</li>
<li>a lot of profiling and tuning of the code, speedup patch
forxmlSearchNs() by Luca Padovani. The xmlReader should do far
lessallocation and it speed should get closer to SAX. Chris Anderson
workedon speeding and cleaning up repetitive checking code.</li>
<li>cleanup of "make tests"</li>
<li>libxml-2.0-uninstalled.pc from Malcolm Tredinnick</li>
<li>deactivated the broken docBook SGML parser code and plugged the
XMLparser instead.</li>
</ul>
<h3>2.5.11: Sep 9 2003</h3>
<p>A bugfix only release:</p>
<ul>
<li>risk of crash in Relax-NG</li>
<li>risk of crash when using multithreaded programs</li>
</ul>
<h3>2.5.10: Aug 15 2003</h3>
<p>A bugfixes only release</p>
<ul>
<li>Windows Makefiles (William Brack)</li>
<li>UTF-16 support fixes (Mark Itzcovitz)</li>
<li>Makefile and portability (William Brack) automake, Linux alpha, Mingwon
Windows (Mikhail Grushinskiy)</li>
<li>HTML parser (Oliver Stoeneberg)</li>
<li>XInclude performance problem reported by Kevin Ruscoe</li>
<li>XML parser performance problem reported by Grant Goodale</li>
<li>xmlSAXParseDTD() bug fix from Malcolm Tredinnick</li>
<li>and a couple other cleanup</li>
</ul>
<h3>2.5.9: Aug 9 2003</h3>
<ul>
<li>bugfixes: IPv6 portability, xmlHasNsProp (Markus Keim), Windows
build(Wiliam Brake, Jesse Pelton, Igor), Schemas (Peter Sobisch),
threading(Rob Richards), hexBinary type (), UTF-16 BOM (Dodji
Seketeli),xmlReader, Relax-NG schemas compilation, namespace handling,
EXSLT (SeanGriffin), HTML parsing problem (William Brack), DTD validation
for mixedcontent + namespaces, HTML serialization, library
initialization,progressive HTML parser</li>
<li>better interfaces for Relax-NG error handling (Joachim Bauch, )</li>
<li>adding xmlXIncludeProcessTree() for XInclud'ing in a subtree</li>
<li>doc fixes and improvements (John Fleck)</li>
<li>configure flag for -with-fexceptions when embedding in C++</li>
<li>couple of new UTF-8 helper functions (William Brack)</li>
<li>general encoding cleanup + ISO-8859-x without iconv (Peter Jacobi)</li>
<li>xmlTextReader cleanup + enum for node types (Bjorn Reese)</li>
<li>general compilation/warning cleanup Solaris/HP-UX/...
(WilliamBrack)</li>
</ul>
<h3>2.5.8: Jul 6 2003</h3>
<ul>
<li>bugfixes: XPath, XInclude, file/URI mapping, UTF-16 save
(MarkItzcovitz), UTF-8 checking, URI saving, error printing (William
Brack),PI related memleak, compilation without schemas or without xpath
(JoergSchmitz-Linneweber/Garry Pennington), xmlUnlinkNode problem with
DTDs,rpm problem on , i86_64, removed a few compilation problems from
2.5.7,xmlIOParseDTD, and xmlSAXParseDTD (Malcolm Tredinnick)</li>
<li>portability: DJGPP (MsDos) , OpenVMS (Craig A. Berry)</li>
<li>William Brack fixed multithreading lock problems</li>
<li>IPv6 patch for FTP and HTTP accesses (Archana Shah/Wipro)</li>
<li>Windows fixes (Igor Zlatkovic, Eric Zurcher), threading
(StéphaneBidoul)</li>
<li>A few W3C Schemas Structure improvements</li>
<li>W3C Schemas Datatype improvements (Charlie Bozeman)</li>
<li>Python bindings for thread globals (Stéphane Bidoul), and
method/classgenerator</li>
<li>added --nonet option to xmllint</li>
<li>documentation improvements (John Fleck)</li>
</ul>
<h3>2.5.7: Apr 25 2003</h3>
<ul>
<li>Relax-NG: Compiling to regexp and streaming validation on top of
thexmlReader interface, added to xmllint --stream</li>
<li>xmlReader: Expand(), Next() and DOM access glue, bug fixes</li>
<li>Support for large files: RGN validated a 4.5GB instance</li>
<li>Thread support is now configured in by default</li>
<li>Fixes: update of the Trio code (Bjorn), WXS Date and Duration
fixes(Charles Bozeman), DTD and namespaces (Brent Hendricks), HTML push
parserand zero bytes handling, some missing Windows file path
conversions,behaviour of the parser and validator in the presence of "out
of memory"error conditions</li>
<li>extended the API to be able to plug a garbage collecting
memoryallocator, added xmlMallocAtomic() and modified the
allocationsaccordingly.</li>
<li>Performances: removed excessive malloc() calls, speedup of the push
andxmlReader interfaces, removed excessive thread locking</li>
<li>Documentation: man page (John Fleck), xmlReader documentation</li>
<li>Python: adding binding for xmlCatalogAddLocal (Brent M Hendricks)</li>
</ul>
<h3>2.5.6: Apr 1 2003</h3>
<ul>
<li>Fixed W3C XML Schemas datatype, should be compliant now except
forbinHex and base64 which are not supported yet.</li>
<li>bug fixes: non-ASCII IDs, HTML output, XInclude on large docs
andXInclude entities handling, encoding detection on external subsets,
XMLSchemas bugs and memory leaks, HTML parser (James Bursa)</li>
<li>portability: python/trio (Albert Chin), Sun compiler warnings</li>
<li>documentation: added --relaxng option to xmllint man page (John)</li>
<li>improved error reporting: xml:space, start/end tag mismatches, Relax
NGerrors</li>
</ul>
<h3>2.5.5: Mar 24 2003</h3>
<ul>
<li>Lot of fixes on the Relax NG implementation. More testing
includingDocBook and TEI examples.</li>
<li>Increased the support for W3C XML Schemas datatype</li>
<li>Several bug fixes in the URI handling layer</li>
<li>Bug fixes: HTML parser, xmlReader, DTD validation, XPath,
encodingconversion, line counting in the parser.</li>
<li>Added support for $XMLLINT_INDENT environment variable, FTP delete</li>
<li>Fixed the RPM spec file name</li>
</ul>
<h3>2.5.4: Feb 20 2003</h3>
<ul>
<li>Conformance testing and lot of fixes on Relax NG and
XIncludeimplementation</li>
<li>Implementation of XPointer element() scheme</li>
<li>Bug fixes: XML parser, XInclude entities merge, validity checking
onnamespaces,
<p>2 serialization bugs, node info generation problems, a DTD
regexpgeneration problem.</p>
</li>
<li>Portability: windows updates and path canonicalization (Igor)</li>
<li>A few typo fixes (Kjartan Maraas)</li>
<li>Python bindings generator fixes (Stephane Bidoul)</li>
</ul>
<h3>2.5.3: Feb 10 2003</h3>
<ul>
<li>RelaxNG and XML Schemas datatypes improvements, and added a
firstversion of RelaxNG Python bindings</li>
<li>Fixes: XLink (Sean Chittenden), XInclude (Sean Chittenden), API fix
forserializing namespace nodes, encoding conversion bug,
XHTML1serialization</li>
<li>Portability fixes: Windows (Igor), AMD 64bits RPM spec file</li>
</ul>
<h3>2.5.2: Feb 5 2003</h3>
<ul>
<li>First implementation of RelaxNG, added --relaxng flag to xmllint</li>
<li>Schemas support now compiled in by default.</li>
<li>Bug fixes: DTD validation, namespace checking, XInclude and
entities,delegateURI in XML Catalogs, HTML parser, XML reader (Stéphane
Bidoul),XPath parser and evaluation, UTF8ToUTF8 serialization, XML
reader memoryconsumption, HTML parser, HTML serialization in the presence
ofnamespaces</li>
<li>added an HTML API to check elements and attributes.</li>
<li>Documentation improvement, PDF for the tutorial (John Fleck),
docpatches (Stefan Kost)</li>
<li>Portability fixes: NetBSD (Julio Merino), Windows (Igor Zlatkovic)</li>
<li>Added python bindings for XPointer, contextual error reporting(Stéphane
Bidoul)</li>
<li>URI/file escaping problems (Stefano Zacchiroli)</li>
</ul>
<h3>2.5.1: Jan 8 2003</h3>
<ul>
<li>Fixes a memory leak and configuration/compilation problems in 2.5.0</li>
<li>documentation updates (John)</li>
<li>a couple of XmlTextReader fixes</li>
</ul>
<h3>2.5.0: Jan 6 2003</h3>
<ul>
<li>New <a href="xmlreader.html">XmltextReader interface</a>based on C#API
(with help of Stéphane Bidoul)</li>
<li>Windows: more exports, including the new API (Igor)</li>
<li>XInclude fallback fix</li>
<li>Python: bindings for the new API, packaging (Stéphane
Bidoul),drv_libxml2.py Python xml.sax driver (Stéphane Bidoul), fixes,
speedupand iterators for Python-2.2 (Hannu Krosing)</li>
<li>Tutorial fixes (john Fleck and Niraj Tolia) xmllint man
update(John)</li>
<li>Fix an XML parser bug raised by Vyacheslav Pindyura</li>
<li>Fix for VMS serialization (Nigel Hall) and config (Craig A. Berry)</li>
<li>Entities handling fixes</li>
<li>new API to optionally track node creation and deletion
(LukasSchroeder)</li>
<li>Added documentation for the XmltextReader interface and some <a
href="guidelines.html">XML guidelines</a></li>
</ul>
<h3>2.4.30: Dec 12 2002</h3>
<ul>
<li>2.4.29 broke the python bindings, rereleasing</li>
<li>Improvement/fixes of the XML API generator, and couple of minor
codefixes.</li>
</ul>
<h3>2.4.29: Dec 11 2002</h3>
<ul>
<li>Windows fixes (Igor): Windows CE port, pthread linking, python
bindings(Stéphane Bidoul), Mingw (Magnus Henoch), and export list
updates</li>
<li>Fix for prev in python bindings (ERDI Gergo)</li>
<li>Fix for entities handling (Marcus Clarke)</li>
<li>Refactored the XML and HTML dumps to a single code path, fixed
XHTML1dump</li>
<li>Fix for URI parsing when handling URNs with fragment identifiers</li>
<li>Fix for HTTP URL escaping problem</li>
<li>added an TextXmlReader (C#) like API (work in progress)</li>
<li>Rewrote the API in XML generation script, includes a C parser and
savesmore informations needed for C# bindings</li>
</ul>
<h3>2.4.28: Nov 22 2002</h3>
<ul>
<li>a couple of python binding fixes</li>
<li>2 bug fixes in the XML push parser</li>
<li>potential memory leak removed (Martin Stoilov)</li>
<li>fix to the configure script for Unix (Dimitri Papadopoulos)</li>
<li>added encoding support for XInclude parse="text"</li>
<li>autodetection of XHTML1 and specific serialization rules added</li>
<li>nasty threading bug fixed (William Brack)</li>
</ul>
<h3>2.4.27: Nov 17 2002</h3>
<ul>
<li>fixes for the Python bindings</li>
<li>a number of bug fixes: SGML catalogs,
xmlParseBalancedChunkMemory(),HTML parser, Schemas (Charles Bozeman),
document fragment support(Christian Glahn), xmlReconciliateNs (Brian
Stafford), XPointer,xmlFreeNode(), xmlSAXParseMemory (Peter Jones),
xmlGetNodePath (PetrPajas), entities processing</li>
<li>added grep to xmllint --shell</li>
<li>VMS update patch from Craig A. Berry</li>
<li>cleanup of the Windows build with support for more compilers
(Igor),better thread support on Windows</li>
<li>cleanup of Unix Makefiles and spec file</li>
<li>Improvements to the documentation (John Fleck)</li>
</ul>
<h3>2.4.26: Oct 18 2002</h3>
<ul>
<li>Patches for Windows CE port, improvements on Windows paths handling</li>
<li>Fixes to the validation code (DTD and Schemas), xmlNodeGetPath() ,HTML
serialization, Namespace compliance, and a number of smallproblems</li>
</ul>
<h3>2.4.25: Sep 26 2002</h3>
<ul>
<li>A number of bug fixes: XPath, validation, Python bindings, DOM andtree,
xmlI/O, Html</li>
<li>Serious rewrite of XInclude</li>
<li>Made XML Schemas regexp part of the default build and APIs, small
fixand improvement of the regexp core</li>
<li>Changed the validation code to reuse XML Schemas regexp APIs</li>
<li>Better handling of Windows file paths, improvement of Makefiles
(Igor,Daniel Gehriger, Mark Vakoc)</li>
<li>Improved the python I/O bindings, the tests, added resolver and
regexpAPIs</li>
<li>New logos from Marc Liyanage</li>
<li>Tutorial improvements: John Fleck, Christopher Harris</li>
<li>Makefile: Fixes for AMD x86_64 (Mandrake), DESTDIR
(ChristopheMerlet)</li>
<li>removal of all stderr/perror use for error reporting</li>
<li>Better error reporting: XPath and DTD validation</li>
<li>update of the trio portability layer (Bjorn Reese)</li>
</ul>
<p><strong>2.4.24: Aug 22 2002</strong></p>
<ul>
<li>XPath fixes (William), xf:escape-uri() (Wesley Terpstra)</li>
<li>Python binding fixes: makefiles (William), generator, rpm build,
x86-64(fcrozat)</li>
<li>HTML &lt;style&gt; and boolean attributes serializer fixes</li>
<li>C14N improvements by Aleksey</li>
<li>doc cleanups: Rick Jones</li>
<li>Windows compiler makefile updates: Igor and Elizabeth Barham</li>
<li>XInclude: implementation of fallback and xml:base fixup added</li>
</ul>
<h3>2.4.23: July 6 2002</h3>
<ul>
<li>performances patches: Peter Jacobi</li>
<li>c14n fixes, testsuite and performances: Aleksey Sanin</li>
<li>added xmlDocFormatDump: Chema Celorio</li>
<li>new tutorial: John Fleck</li>
<li>new hash functions and performances: Sander Vesik, portability fix
fromPeter Jacobi</li>
<li>a number of bug fixes: XPath (William Brack, Richard Jinks), XML
andHTML parsers, ID lookup function</li>
<li>removal of all remaining sprintf: Aleksey Sanin</li>
</ul>
<h3>2.4.22: May 27 2002</h3>
<ul>
<li>a number of bug fixes: configure scripts, base handling, parser,
memoryusage, HTML parser, XPath, documentation (Christian
Cornelssen),indentation, URI parsing</li>
<li>Optimizations for XMLSec, fixing and making public some of the
networkprotocol handlers (Aleksey)</li>
<li>performance patch from Gary Pennington</li>
<li>Charles Bozeman provided date and time support for XML
Schemasdatatypes</li>
</ul>
<h3>2.4.21: Apr 29 2002</h3>
<p>This release is both a bug fix release and also contains the early
XMLSchemas <a href="http://www.w3.org/TR/xmlschema-1/">structures</a>and <a
href="http://www.w3.org/TR/xmlschema-2/">datatypes</a>code, beware,
allinterfaces are likely to change, there is huge holes, it is clearly a work
inprogress and don't even think of putting this code in a production
system,it's actually not compiled in by default. The real fixes are:</p>
<ul>
<li>a couple of bugs or limitations introduced in 2.4.20</li>
<li>patches for Borland C++ and MSC by Igor</li>
<li>some fixes on XPath strings and conformance patches by RichardJinks</li>
<li>patch from Aleksey for the ExcC14N specification</li>
<li>OSF/1 bug fix by Bjorn</li>
</ul>
<h3>2.4.20: Apr 15 2002</h3>
<ul>
<li>bug fixes: file descriptor leak, XPath, HTML output, DTD validation</li>
<li>XPath conformance testing by Richard Jinks</li>
<li>Portability fixes: Solaris, MPE/iX, Windows, OSF/1, python
bindings,libxml.m4</li>
</ul>
<h3>2.4.19: Mar 25 2002</h3>
<ul>
<li>bug fixes: half a dozen XPath bugs, Validation, ISO-Latin to
UTF8encoder</li>
<li>portability fixes in the HTTP code</li>
<li>memory allocation checks using valgrind, and profiling tests</li>
<li>revamp of the Windows build and Makefiles</li>
</ul>
<h3>2.4.18: Mar 18 2002</h3>
<ul>
<li>bug fixes: tree, SAX, canonicalization, validation,
portability,XPath</li>
<li>removed the --with-buffer option it was becoming unmaintainable</li>
<li>serious cleanup of the Python makefiles</li>
<li>speedup patch to XPath very effective for DocBook stylesheets</li>
<li>Fixes for Windows build, cleanup of the documentation</li>
</ul>
<h3>2.4.17: Mar 8 2002</h3>
<ul>
<li>a lot of bug fixes, including "namespace nodes have no parents
inXPath"</li>
<li>fixed/improved the Python wrappers, added more examples and
moreregression tests, XPath extension functions can now return
node-sets</li>
<li>added the XML Canonicalization support from Aleksey Sanin</li>
</ul>
<h3>2.4.16: Feb 20 2002</h3>
<ul>
<li>a lot of bug fixes, most of them were triggered by the XML
Testsuitefrom OASIS and W3C. Compliance has been significantly
improved.</li>
<li>a couple of portability fixes too.</li>
</ul>
<h3>2.4.15: Feb 11 2002</h3>
<ul>
<li>Fixed the Makefiles, especially the python module ones</li>
<li>A few bug fixes and cleanup</li>
<li>Includes cleanup</li>
</ul>
<h3>2.4.14: Feb 8 2002</h3>
<ul>
<li>Change of License to the <a
href="http://www.opensource.org/licenses/mit-license.html">MITLicense</a>basically
for integration in XFree86 codebase, and removingconfusion around the
previous dual-licensing</li>
<li>added Python bindings, beta software but should already be
quitecomplete</li>
<li>a large number of fixes and cleanups, especially for all
treemanipulations</li>
<li>cleanup of the headers, generation of a reference API definition
inXML</li>
</ul>
<h3>2.4.13: Jan 14 2002</h3>
<ul>
<li>update of the documentation: John Fleck and Charlie Bozeman</li>
<li>cleanup of timing code from Justin Fletcher</li>
<li>fixes for Windows and initial thread support on Win32: Igor and
SergueiNarojnyi</li>
<li>Cygwin patch from Robert Collins</li>
<li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li>
</ul>
<h3>2.4.12: Dec 7 2001</h3>
<ul>
<li>a few bug fixes: thread (Gary Pennington), xmllint (Geert
Kloosterman),XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O
cleanups(robert)</li>
<li>Eric Lavigne contributed project files for MacOS</li>
<li>some makefiles cleanups</li>
</ul>
<h3>2.4.11: Nov 26 2001</h3>
<ul>
<li>fixed a couple of errors in the includes, fixed a few bugs, some
codecleanups</li>
<li>xmllint man pages improvement by Heiko Rupp</li>
<li>updated VMS build instructions from John A Fotheringham</li>
<li>Windows Makefiles updates from Igor</li>
</ul>
<h3>2.4.10: Nov 10 2001</h3>
<ul>
<li>URI escaping fix (Joel Young)</li>
<li>added xmlGetNodePath() (for paths or XPointers generation)</li>
<li>Fixes namespace handling problems when using DTD and validation</li>
<li>improvements on xmllint: Morus Walter patches for --format and--encode,
Stefan Kost and Heiko Rupp improvements on the --shell</li>
<li>fixes for xmlcatalog linking pointed by Weiqi Gao</li>
<li>fixes to the HTML parser</li>
</ul>
<h3>2.4.9: Nov 6 2001</h3>
<ul>
<li>fixes more catalog bugs</li>
<li>avoid a compilation problem, improve xmlGetLineNo()</li>
</ul>
<h3>2.4.8: Nov 4 2001</h3>
<ul>
<li>fixed SGML catalogs broken in previous release, updated
xmlcatalogtool</li>
<li>fixed a compile errors and some includes troubles.</li>
</ul>
<h3>2.4.7: Oct 30 2001</h3>
<ul>
<li>exported some debugging interfaces</li>
<li>serious rewrite of the catalog code</li>
<li>integrated Gary Pennington thread safety patch, added configure
optionand regression tests</li>
<li>removed an HTML parser bug</li>
<li>fixed a couple of potentially serious validation bugs</li>
<li>integrated the SGML DocBook support in xmllint</li>
<li>changed the nanoftp anonymous login passwd</li>
<li>some I/O cleanup and a couple of interfaces for Perl wrapper</li>
<li>general bug fixes</li>
<li>updated xmllint man page by John Fleck</li>
<li>some VMS and Windows updates</li>
</ul>
<h3>2.4.6: Oct 10 2001</h3>
<ul>
<li>added an updated man pages by John Fleck</li>
<li>portability and configure fixes</li>
<li>an infinite loop on the HTML parser was removed (William)</li>
<li>Windows makefile patches from Igor</li>
<li>fixed half a dozen bugs reported for libxml or libxslt</li>
<li>updated xmlcatalog to be able to modify SGML super catalogs</li>
</ul>
<h3>2.4.5: Sep 14 2001</h3>
<ul>
<li>Remove a few annoying bugs in 2.4.4</li>
<li>forces the HTML serializer to output decimal charrefs since someversion
of Netscape can't handle hexadecimal ones</li>
</ul>
<h3>1.8.16: Sep 14 2001</h3>
<ul>
<li>maintenance release of the old libxml1 branch, couple of bug
andportability fixes</li>
</ul>
<h3>2.4.4: Sep 12 2001</h3>
<ul>
<li>added --convert to xmlcatalog, bug fixes and cleanups of XMLCatalog</li>
<li>a few bug fixes and some portability changes</li>
<li>some documentation cleanups</li>
</ul>
<h3>2.4.3: Aug 23 2001</h3>
<ul>
<li>XML Catalog support see the doc</li>
<li>New NaN/Infinity floating point code</li>
<li>A few bug fixes</li>
</ul>
<h3>2.4.2: Aug 15 2001</h3>
<ul>
<li>adds xmlLineNumbersDefault() to control line number generation</li>
<li>lot of bug fixes</li>
<li>the Microsoft MSC projects files should now be up to date</li>
<li>inheritance of namespaces from DTD defaulted attributes</li>
<li>fixes a serious potential security bug</li>
<li>added a --format option to xmllint</li>
</ul>
<h3>2.4.1: July 24 2001</h3>
<ul>
<li>possibility to keep line numbers in the tree</li>
<li>some computation NaN fixes</li>
<li>extension of the XPath API</li>
<li>cleanup for alpha and ia64 targets</li>
<li>patch to allow saving through HTTP PUT or POST</li>
</ul>
<h3>2.4.0: July 10 2001</h3>
<ul>
<li>Fixed a few bugs in XPath, validation, and tree handling.</li>
<li>Fixed XML Base implementation, added a couple of examples to
theregression tests</li>
<li>A bit of cleanup</li>
</ul>
<h3>2.3.14: July 5 2001</h3>
<ul>
<li>fixed some entities problems and reduce memory requirement
whensubstituting them</li>
<li>lots of improvements in the XPath queries interpreter can
besubstantially faster</li>
<li>Makefiles and configure cleanups</li>
<li>Fixes to XPath variable eval, and compare on empty node set</li>
<li>HTML tag closing bug fixed</li>
<li>Fixed an URI reference computation problem when validating</li>
</ul>
<h3>2.3.13: June 28 2001</h3>
<ul>
<li>2.3.12 configure.in was broken as well as the push mode XML parser</li>
<li>a few more fixes for compilation on Windows MSC by Yon Derek</li>
</ul>
<h3>1.8.14: June 28 2001</h3>
<ul>
<li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li>
<li>Small Makefile fix</li>
</ul>
<h3>2.3.12: June 26 2001</h3>
<ul>
<li>lots of cleanup</li>
<li>a couple of validation fix</li>
<li>fixed line number counting</li>
<li>fixed serious problems in the XInclude processing</li>
<li>added support for UTF8 BOM at beginning of entities</li>
<li>fixed a strange gcc optimizer bugs in xpath handling of float,
gcc-3.0miscompile uri.c (William), Thomas Leitner provided a fix for
theoptimizer on Tru64</li>
<li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements
forcompilation on Windows MSC</li>
<li>update of libxml-doc.el (Felix Natter)</li>
<li>fixed 2 bugs in URI normalization code</li>
</ul>
<h3>2.3.11: June 17 2001</h3>
<ul>
<li>updates to trio, Makefiles and configure should fix some
portabilityproblems (alpha)</li>
<li>fixed some HTML serialization problems (pre, script, and
block/inlinehandling), added encoding aware APIs, cleanup of this
code</li>
<li>added xmlHasNsProp()</li>
<li>implemented a specific PI for encoding support in the DocBook
SGMLparser</li>
<li>some XPath fixes (-Infinity, / as a function parameter and
namespacesnode selection)</li>
<li>fixed a performance problem and an error in the validation code</li>
<li>fixed XInclude routine to implement the recursive behaviour</li>
<li>fixed xmlFreeNode problem when libxml is included statically twice</li>
<li>added --version to xmllint for bug reports</li>
</ul>
<h3>2.3.10: June 1 2001</h3>
<ul>
<li>fixed the SGML catalog support</li>
<li>a number of reported bugs got fixed, in XPath, iconv detection,XInclude
processing</li>
<li>XPath string function should now handle unicode correctly</li>
</ul>
<h3>2.3.9: May 19 2001</h3>
<p>Lots of bugfixes, and added a basic SGML catalog support:</p>
<ul>
<li>HTML push bugfix #54891 and another patch from Jonas Borgström</li>
<li>some serious speed optimization again</li>
<li>some documentation cleanups</li>
<li>trying to get better linking on Solaris (-R)</li>
<li>XPath API cleanup from Thomas Broyer</li>
<li>Validation bug fixed #54631, added a patch from Gary Pennington,
fixedxmlValidGetValidElements()</li>
<li>Added an INSTALL file</li>
<li>Attribute removal added to API: #54433</li>
<li>added a basic support for SGML catalogs</li>
<li>fixed xmlKeepBlanksDefault(0) API</li>
<li>bugfix in xmlNodeGetLang()</li>
<li>fixed a small configure portability problem</li>
<li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li>
</ul>
<h3>1.8.13: May 14 2001</h3>
<ul>
<li>bugfixes release of the old libxml1 branch used by Gnome</li>
</ul>
<h3>2.3.8: May 3 2001</h3>
<ul>
<li>Integrated an SGML DocBook parser for the Gnome project</li>
<li>Fixed a few things in the HTML parser</li>
<li>Fixed some XPath bugs raised by XSLT use, tried to fix the
floatingpoint portability issue</li>
<li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s forDOM+validation
using the XML REC as input and a 700MHz celeron).</li>
<li>incorporated more Windows cleanup</li>
<li>added xmlSaveFormatFile()</li>
<li>fixed problems in copying nodes with entities references (gdome)</li>
<li>removed some troubles surrounding the new validation module</li>
</ul>
<h3>2.3.7: April 22 2001</h3>
<ul>
<li>lots of small bug fixes, corrected XPointer</li>
<li>Non deterministic content model validation support</li>
<li>added xmlDocCopyNode for gdome2</li>
<li>revamped the way the HTML parser handles end of tags</li>
<li>XPath: corrections of namespaces support and number formatting</li>
<li>Windows: Igor Zlatkovic patches for MSC compilation</li>
<li>HTML output fixes from P C Chow and William M. Brack</li>
<li>Improved validation speed sensible for DocBook</li>
<li>fixed a big bug with ID declared in external parsed entities</li>
<li>portability fixes, update of Trio from Bjorn Reese</li>
</ul>
<h3>2.3.6: April 8 2001</h3>
<ul>
<li>Code cleanup using extreme gcc compiler warning options, found
andcleared half a dozen potential problem</li>
<li>the Eazel team found an XML parser bug</li>
<li>cleaned up the user of some of the string formatting function. used
thetrio library code to provide the one needed when the platform is
missingthem</li>
<li>xpath: removed a memory leak and fixed the predicate evaluationproblem,
extended the testsuite and cleaned up the result. XPointer seemsbroken
...</li>
</ul>
<h3>2.3.5: Mar 23 2001</h3>
<ul>
<li>Biggest change is separate parsing and evaluation of XPath
expressions,there is some new APIs for this too</li>
<li>included a number of bug fixes(XML push parser, 51876,
notations,52299)</li>
<li>Fixed some portability issues</li>
</ul>
<h3>2.3.4: Mar 10 2001</h3>
<ul>
<li>Fixed bugs #51860 and #51861</li>
<li>Added a global variable xmlDefaultBufferSize to allow default
buffersize to be application tunable.</li>
<li>Some cleanup in the validation code, still a bug left and this
partshould probably be rewritten to support ambiguous content model
:-\</li>
<li>Fix a couple of serious bugs introduced or raised by changes in
2.3.3parser</li>
<li>Fixed another bug in xmlNodeGetContent()</li>
<li>Bjorn fixed XPath node collection and Number formatting</li>
<li>Fixed a loop reported in the HTML parsing</li>
<li>blank space are reported even if the Dtd content model proves that
theyare formatting spaces, this is for XML conformance</li>
</ul>
<h3>2.3.3: Mar 1 2001</h3>
<ul>
<li>small change in XPath for XSLT</li>
<li>documentation cleanups</li>
<li>fix in validation by Gary Pennington</li>
<li>serious parsing performances improvements</li>
</ul>
<h3>2.3.2: Feb 24 2001</h3>
<ul>
<li>chasing XPath bugs, found a bunch, completed some TODO</li>
<li>fixed a Dtd parsing bug</li>
<li>fixed a bug in xmlNodeGetContent</li>
<li>ID/IDREF support partly rewritten by Gary Pennington</li>
</ul>
<h3>2.3.1: Feb 15 2001</h3>
<ul>
<li>some XPath and HTML bug fixes for XSLT</li>
<li>small extension of the hash table interfaces for DOM
gdome2implementation</li>
<li>A few bug fixes</li>
</ul>
<h3>2.3.0: Feb 8 2001 (2.2.12 was on 25 Jan but I didn't kept track)</h3>
<ul>
<li>Lots of XPath bug fixes</li>
<li>Add a mode with Dtd lookup but without validation error reporting
forXSLT</li>
<li>Add support for text node without escaping (XSLT)</li>
<li>bug fixes for xmlCheckFilename</li>
<li>validation code bug fixes from Gary Pennington</li>
<li>Patch from Paul D. Smith correcting URI path normalization</li>
<li>Patch to allow simultaneous install of libxml-devel
andlibxml2-devel</li>
<li>the example Makefile is now fixed</li>
<li>added HTML to the RPM packages</li>
<li>tree copying bugfixes</li>
<li>updates to Windows makefiles</li>
<li>optimization patch from Bjorn Reese</li>
</ul>
<h3>2.2.11: Jan 4 2001</h3>
<ul>
<li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
<li>added htmlHandleOmittedElem()</li>
<li>Applied Bjorn Reese's IPV6 first patch</li>
<li>Applied Paul D. Smith patches for validation of XInclude results</li>
<li>added XPointer xmlns() new scheme support</li>
</ul>
<h3>2.2.10: Nov 25 2000</h3>
<ul>
<li>Fix the Windows problems of 2.2.8</li>
<li>integrate OpenVMS patches</li>
<li>better handling of some nasty HTML input</li>
<li>Improved the XPointer implementation</li>
<li>integrate a number of provided patches</li>
</ul>
<h3>2.2.9: Nov 25 2000</h3>
<ul>
<li>erroneous release :-(</li>
</ul>
<h3>2.2.8: Nov 13 2000</h3>
<ul>
<li>First version of <a
href="http://www.w3.org/TR/xinclude">XInclude</a>support</li>
<li>Patch in conditional section handling</li>
<li>updated MS compiler project</li>
<li>fixed some XPath problems</li>
<li>added an URI escaping function</li>
<li>some other bug fixes</li>
</ul>
<h3>2.2.7: Oct 31 2000</h3>
<ul>
<li>added message redirection</li>
<li>XPath improvements (thanks TOM !)</li>
<li>xmlIOParseDTD() added</li>
<li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
<li>some cleanup of the Makefile, autoconf and the distribution content</li>
</ul>
<h3>2.2.6: Oct 25 2000:</h3>
<ul>
<li>Added an hash table module, migrated a number of internal structure
tothose</li>
<li>Fixed a posteriori validation problems</li>
<li>HTTP module cleanups</li>
<li>HTML parser improvements (tag errors, script/style handling,
attributenormalization)</li>
<li>coalescing of adjacent text nodes</li>
<li>couple of XPath bug fixes, exported the internal API</li>
</ul>
<h3>2.2.5: Oct 15 2000:</h3>
<ul>
<li>XPointer implementation and testsuite</li>
<li>Lot of XPath fixes, added variable and functions registration,
moretests</li>
<li>Portability fixes, lots of enhancements toward an easy Windows buildand
release</li>
<li>Late validation fixes</li>
<li>Integrated a lot of contributed patches</li>
<li>added memory management docs</li>
<li>a performance problem when using large buffer seems fixed</li>
</ul>
<h3>2.2.4: Oct 1 2000:</h3>
<ul>
<li>main XPath problem fixed</li>
<li>Integrated portability patches for Windows</li>
<li>Serious bug fixes on the URI and HTML code</li>
</ul>
<h3>2.2.3: Sep 17 2000</h3>
<ul>
<li>bug fixes</li>
<li>cleanup of entity handling code</li>
<li>overall review of all loops in the parsers, all sprintf usage has
beenchecked too</li>
<li>Far better handling of larges Dtd. Validating against DocBook XML
Dtdworks smoothly now.</li>
</ul>
<h3>1.8.10: Sep 6 2000</h3>
<ul>
<li>bug fix release for some Gnome projects</li>
</ul>
<h3>2.2.2: August 12 2000</h3>
<ul>
<li>mostly bug fixes</li>
<li>started adding routines to access xml parser context options</li>
</ul>
<h3>2.2.1: July 21 2000</h3>
<ul>
<li>a purely bug fixes release</li>
<li>fixed an encoding support problem when parsing from a memory block</li>
<li>fixed a DOCTYPE parsing problem</li>
<li>removed a bug in the function allowing to override the memoryallocation
routines</li>
</ul>
<h3>2.2.0: July 14 2000</h3>
<ul>
<li>applied a lot of portability fixes</li>
<li>better encoding support/cleanup and saving (content is now
alwaysencoded in UTF-8)</li>
<li>the HTML parser now correctly handles encodings</li>
<li>added xmlHasProp()</li>
<li>fixed a serious problem with &amp;#38;</li>
<li>propagated the fix to FTP client</li>
<li>cleanup, bugfixes, etc ...</li>
<li>Added a page about <a href="encoding.html">libxml
Internationalizationsupport</a></li>
</ul>
<h3>1.8.9: July 9 2000</h3>
<ul>
<li>fixed the spec the RPMs should be better</li>
<li>fixed a serious bug in the FTP implementation, released 1.8.9 to
solverpmfind users problem</li>
</ul>
<h3>2.1.1: July 1 2000</h3>
<ul>
<li>fixes a couple of bugs in the 2.1.0 packaging</li>
<li>improvements on the HTML parser</li>
</ul>
<h3>2.1.0 and 1.8.8: June 29 2000</h3>
<ul>
<li>1.8.8 is mostly a commodity package for upgrading to libxml2
accordingto <a href="upgrade.html">new instructions</a>. It fixes a nasty
problemabout &amp;#38; charref parsing</li>
<li>2.1.0 also ease the upgrade from libxml v1 to the recent version.
italso contains numerous fixes and enhancements:
<ul>
<li>added xmlStopParser() to stop parsing</li>
<li>improved a lot parsing speed when there is large CDATA blocs</li>
<li>includes XPath patches provided by Picdar Technology</li>
<li>tried to fix as much as possible DTD validation and
namespacerelated problems</li>
<li>output to a given encoding has been added/tested</li>
<li>lot of various fixes</li>
</ul>
</li>
</ul>
<h3>2.0.0: Apr 12 2000</h3>
<ul>
<li>First public release of libxml2. If you are using libxml, it's a
goodidea to check the 1.x to 2.x upgrade instructions. NOTE: while
initiallyscheduled for Apr 3 the release occurred only on Apr 12 due to
massiveworkload.</li>
<li>The include are now located under $prefix/include/libxml (instead
of$prefix/include/gnome-xml), they also are referenced by
<pre>#include &lt;libxml/xxx.h&gt;</pre>
<p>instead of</p>
<pre>#include "xxx.h"</pre>
</li>
<li>a new URI module for parsing URIs and following strictly RFC 2396</li>
<li>the memory allocation routines used by libxml can now be
overloadeddynamically by using xmlMemSetup()</li>
<li>The previously CVS only tool tester has been
renamed<strong>xmllint</strong>and is now installed as part of the
libxml2package</li>
<li>The I/O interface has been revamped. There is now ways to plug
inspecific I/O modules, either at the URI scheme detection level
usingxmlRegisterInputCallbacks() or by passing I/O functions when
creating aparser context using xmlCreateIOParserCtxt()</li>
<li>there is a C preprocessor macro LIBXML_VERSION providing the
versionnumber of the libxml module in use</li>
<li>a number of optional features of libxml can now be excluded atconfigure
time (FTP/HTTP/HTML/XPath/Debug)</li>
</ul>
<h3>2.0.0beta: Mar 14 2000</h3>
<ul>
<li>This is a first Beta release of libxml version 2</li>
<li>It's available only from<a
href="ftp://xmlsoft.org/libxml2/">xmlsoft.orgFTP</a>, it's packaged as
libxml2-2.0.0beta and available as tar andRPMs</li>
<li>This version is now the head in the Gnome CVS base, the old one
isavailable under the tag LIB_XML_1_X</li>
<li>This includes a very large set of changes. From a programmatic pointof
view applications should not have to be modified too much, check the<a
href="upgrade.html">upgrade page</a></li>
<li>Some interfaces may changes (especially a bit about encoding).</li>
<li>the updates includes:
<ul>
<li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems
correctlyhandled now</li>
<li>Better handling of entities, especially well-formedness checkingand
proper PEref extensions in external subsets</li>
<li>DTD conditional sections</li>
<li>Validation now correctly handle entities content</li>
<li><a
href="http://rpmfind.net/tools/gdome/messages/0039.html">changestructures
to accommodate DOM</a></li>
</ul>
</li>
<li>Serious progress were made toward compliance, <a
href="conf/result.html">here are the result of the test</a>against
theOASIS testsuite (except the Japanese tests since I don't support
thatencoding yet). This URL is rebuilt every couple of hours using the
CVShead version.</li>
</ul>
<h3>1.8.7: Mar 6 2000</h3>
<ul>
<li>This is a bug fix release:</li>
<li>It is possible to disable the ignorable blanks heuristic used
bylibxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this.
Notethat for adherence to XML spec, this behaviour will be disabled
bydefault in 2.x . The same function will allow to keep compatibility
forold code.</li>
<li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored
anymore,avoiding heuristic is really the Right Way :-\</li>
<li>The unchecked use of snprintf which was breaking
libxml-1.8.6compilation on some platforms has been fixed</li>
<li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when
processingURIs</li>
</ul>
<h3>1.8.6: Jan 31 2000</h3>
<ul>
<li>added a nanoFTP transport module, debugged until the new version of <a
href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a>can
useit without troubles</li>
</ul>
<h3>1.8.5: Jan 21 2000</h3>
<ul>
<li>adding APIs to parse a well balanced chunk of XML (production <a
href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a>of theXML
spec)</li>
<li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
<li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch
tryingto solve the zlib checks problems</li>
<li>The current state in gnome CVS base is expected to ship as 1.8.5
withgnumeric soon</li>
</ul>
<h3>1.8.4: Jan 13 2000</h3>
<ul>
<li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
<li>all exit() call should have been removed from libxml</li>
<li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
<li>added newDocFragment()</li>
</ul>
<h3>1.8.3: Jan 5 2000</h3>
<ul>
<li>a Push interface for the XML and HTML parsers</li>
<li>a shell-like interface to the document tree (try tester --shell :-)</li>
<li>lots of bug fixes and improvement added over XMas holidays</li>
<li>fixed the DTD parsing code to work with the xhtml DTD</li>
<li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
<li>Fixed bugs in xmlNewNs()</li>
<li>External entity loading code has been revamped, now it
usesxmlLoadExternalEntity(), some fix on entities processing were
added</li>
<li>cleaned up WIN32 includes of socket stuff</li>
</ul>
<h3>1.8.2: Dec 21 1999</h3>
<ul>
<li>I got another problem with includes and C++, I hope this issue is
fixedfor good this time</li>
<li>Added a few tree modification functions:
xmlReplaceNode,xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName
andxmlDocSetRootElement</li>
<li>Tried to improve the HTML output with help from <a
href="mailto:clahey@umich.edu">Chris Lahey</a></li>
</ul>
<h3>1.8.1: Dec 18 1999</h3>
<ul>
<li>various patches to avoid troubles when using libxml with C++
compilersthe "namespace" keyword and C escaping in include files</li>
<li>a problem in one of the core macros IS_CHAR was corrected</li>
<li>fixed a bug introduced in 1.8.0 breaking default namespace
processing,and more specifically the Dia application</li>
<li>fixed a posteriori validation (validation after parsing, or by using
aDtd not specified in the original document)</li>
<li>fixed a bug in</li>
</ul>
<h3>1.8.0: Dec 12 1999</h3>
<ul>
<li>cleanup, especially memory wise</li>
<li>the parser should be more reliable, especially the HTML one, it
shouldnot crash, whatever the input !</li>
<li>Integrated various patches, especially a speedup improvement for
largedataset from <a href="mailto:cnygard@bellatlantic.net">Carl
Nygard</a>,configure with --with-buffers to enable them.</li>
<li>attribute normalization, oops should have been added long ago !</li>
<li>attributes defaulted from DTDs should be available, xmlSetProp()
nowdoes entities escaping by default.</li>
</ul>
<h3>1.7.4: Oct 25 1999</h3>
<ul>
<li>Lots of HTML improvement</li>
<li>Fixed some errors when saving both XML and HTML</li>
<li>More examples, the regression tests should now look clean</li>
<li>Fixed a bug with contiguous charref</li>
</ul>
<h3>1.7.3: Sep 29 1999</h3>
<ul>
<li>portability problems fixed</li>
<li>snprintf was used unconditionally, leading to link problems on
systemwere it's not available, fixed</li>
</ul>
<h3>1.7.1: Sep 24 1999</h3>
<ul>
<li>The basic type for strings manipulated by libxml has been renamed
in1.7.1 from <strong>CHAR</strong>to <strong>xmlChar</strong>. The
reasonis that CHAR was conflicting with a predefined type on Windows.
Howeveron non WIN32 environment, compatibility is provided by the way of
a<strong>#define </strong>.</li>
<li>Changed another error : the use of a structure field called errno,
andleading to troubles on platforms where it's a macro</li>
</ul>
<h3>1.7.0: Sep 23 1999</h3>
<ul>
<li>Added the ability to fetch remote DTD or parsed entities, see the <a
href="html/libxml-nanohttp.html">nanohttp</a>module.</li>
<li>Added an errno to report errors by another mean than a simple
printflike callback</li>
<li>Finished ID/IDREF support and checking when validation</li>
<li>Serious memory leaks fixed (there is now a <a
href="html/libxml-xmlmemory.html">memory wrapper</a>module)</li>
<li>Improvement of <a
href="http://www.w3.org/TR/xpath">XPath</a>implementation</li>
<li>Added an HTML parser front-end</li>
</ul>
<h2><a name="XML">XML</a></h2>
<p><a href="http://www.w3.org/TR/REC-xml">XML is a
standard</a>formarkup-based structured documents. Here is <a
name="example">an example XMLdocument</a>:</p>
<pre>&lt;?xml version="1.0"?&gt;
&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
&lt;head&gt;
&lt;title&gt;Welcome to Gnome&lt;/title&gt;
&lt;/head&gt;
&lt;chapter&gt;
&lt;title&gt;The Linux adventure&lt;/title&gt;
&lt;p&gt;bla bla bla ...&lt;/p&gt;
&lt;image href="linus.gif"/&gt;
&lt;p&gt;...&lt;/p&gt;
&lt;/chapter&gt;
&lt;/EXAMPLE&gt;</pre>
<p>The first line specifies that it is an XML document and gives
usefulinformation about its encoding. Then the rest of the document is a
textformat whose structure is specified by tags between brackets.
<strong>Eachtag opened has to be closed</strong>. XML is pedantic about this.
However, ifa tag is empty (no content), a single tag can serve as both the
opening andclosing tag if it ends with <code>/&gt;</code>rather than
with<code>&gt;</code>. Note that, for example, the image tag has no content
(justan attribute) and is closed by ending the tag with
<code>/&gt;</code>.</p>
<p>XML can be applied successfully to a wide range of tasks, ranging fromlong
term structured document maintenance (where it follows the steps ofSGML) to
simple data encoding mechanisms like configuration file formatting(glade),
spreadsheets (gnumeric), or even shorter lived documents such asWebDAV where
it is used to encode remote calls between a client and aserver.</p>
<h2><a name="XSLT">XSLT</a></h2>
<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is alanguage
for transforming XML documents into other XML documents (orHTML/textual
output).</p>
<p>A separate library called libxslt is available implementing XSLT-1.0
forlibxml2. This module "libxslt" too can be found in the Gnome CVS base.</p>
<p>You can check the progresses on the libxslt <a
href="http://xmlsoft.org/XSLT/ChangeLog.html">Changelog</a>.</p>
<h2><a name="Python">Python and bindings</a></h2>
<p>There are a number of language bindings and wrappers available forlibxml2,
the list below is not exhaustive. Please contact the <a
href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a>(<a
href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) inorder to
get updates to this list or to discuss the specific topic of libxml2or
libxslt wrappers or bindings:</p>
<ul>
<li><a href="http://libxmlplusplus.sourceforge.net/">Libxml++</a>seems
themost up-to-date C++ bindings for libxml2, check the <a
href="http://libxmlplusplus.sourceforge.net/reference/html/hierarchy.html">documentation</a>and
the <a
href="http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/libxmlplusplus/libxml%2b%2b/examples/">examples</a>.</li>
<li>There is another <a href="http://libgdome-cpp.berlios.de/">C++
wrapperbased on the gdome2 bindings</a>maintained by Tobias Peters.</li>
<li>and a third C++ wrapper by Peter Jones &lt;pjones@pmade.org&gt;
<p>Website: <a
href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
</li>
<li><a
href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">MattSergeant</a>developed
<a href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper
forlibxml2/libxslt as part of the <a href="http://axkit.com/">AxKit
XMLapplication server</a>.</li>
<li>If you're interested into scripting XML processing, have a look at <a
href="http://xsh.sourceforge.net/">XSH</a>an XML editing shell based
onLibxml2 Perl bindings.</li>
<li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a>provides
anearlier version of the libxml/libxslt <a
href="http://www.rexx.com/~dkuhlman">wrappers for Python</a>.</li>
<li>Gopal.V and Peter Minten develop <a
href="http://savannah.gnu.org/projects/libxmlsharp">libxml#</a>, a set
ofC# libxml2 bindings.</li>
<li>Petr Kozelka provides <a
href="http://sourceforge.net/projects/libxml2-pas">Pascal units to
gluelibxml2</a>with Kylix, Delphi and other Pascal compilers.</li>
<li>Uwe Fechner also provides <a
href="http://sourceforge.net/projects/idom2-pas/">idom2</a>, a
DOM2implementation for Kylix2/D5/D6 from Borland.</li>
<li>There is <a href="http://libxml.rubyforge.org/">bindings for
Ruby</a>and libxml2 bindings are also available in Ruby through the <a
href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a>modulemaintained
by Tobias Peters.</li>
<li>Steve Ball and contributors maintains <a
href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings
forTcl</a>.</li>
<li>libxml2 and libxslt is the default XML library for PHP5.</li>
<li><a href="http://savannah.gnu.org/projects/classpathx/">LibxmlJ</a>isan
effort to create a 100% JAXP-compatible Java wrapper for libxml2
andlibxslt as part of GNU ClasspathX project.</li>
<li>Patrick McPhee provides Rexx bindings fof libxml2 and libxslt, look
for<a href="http://www.interlog.com/~ptjm/software.html">RexxXML</a>.</li>
<li><a
href="http://www.satimage.fr/software/en/xml_suite.html">Satimage</a>provides
<a
href="http://www.satimage.fr/software/en/downloads_osaxen.html">XMLLibosax</a>.
This is an osax for Mac OS X with a set of commands toimplement in
AppleScript the XML DOM, XPATH and XSLT. Also includescommands for
Property-lists (Apple's fast lookup table XML format.)</li>
<li>Francesco Montorsi developped <a
href="https://sourceforge.net/project/showfiles.php?group_id=51305&amp;package_id=45182">wxXml2</a>wrappers
that interface libxml2, allowing wxWidgets applications toload/save/edit
XML instances.</li>
</ul>
<p>The distribution includes a set of Python bindings, which are guaranteedto
be maintained as part of the library in the future, though the
Pythoninterface have not yet reached the completeness of the C API.</p>
<p>Note that some of the Python purist dislike the default set of
Pythonbindings, rather than complaining I suggest they have a look at <a
href="http://codespeak.net/lxml/">lxml the more pythonic bindings for
libxml2and libxslt</a>and <a
href="http://codespeak.net/mailman/listinfo/lxml-dev">help
MartijnFaassen</a>complete those.</p>
<p><a href="mailto:stephane.bidoul@softwareag.com">Stéphane
Bidoul</a>maintains <a href="http://users.skynet.be/sbi/libxml-python/">a
Windows portof the Python bindings</a>.</p>
<p>Note to people interested in building bindings, the API is formalized as<a
href="libxml2-api.xml">an XML API description file</a>which allows toautomate
a large part of the Python bindings, this includes functiondescriptions,
enums, structures, typedefs, etc... The Python script used tobuild the
bindings is python/generator.py in the source distribution.</p>
<p>To install the Python bindings there are 2 options:</p>
<ul>
<li>If you use an RPM based distribution, simply install the <a
href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-pythonRPM</a>(and
if needed the <a
href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-pythonRPM</a>).</li>
<li>Otherwise use the <a
href="ftp://xmlsoft.org/libxml2/python/">libxml2-pythonmodule
distribution</a>corresponding to your installed version oflibxml2 and
libxslt. Note that to install it you will need both libxml2and libxslt
installed and run "python setup.py build install" in themodule tree.</li>
</ul>
<p>The distribution includes a set of examples and regression tests for
thepython bindings in the <code>python/tests</code>directory. Here are
someexcerpts from those tests:</p>
<h3>tst.py:</h3>
<p>This is a basic test of the file interface and DOM navigation:</p>
<pre>import libxml2, sys
doc = libxml2.parseFile("tst.xml")
if doc.name != "tst.xml":
print "doc.name failed"
sys.exit(1)
root = doc.children
if root.name != "doc":
print "root.name failed"
sys.exit(1)
child = root.children
if child.name != "foo":
print "child.name failed"
sys.exit(1)
doc.freeDoc()</pre>
<p>The Python module is called libxml2; parseFile is the equivalent
ofxmlParseFile (most of the bindings are automatically generated, and the
xmlprefix is removed and the casing convention are kept). All node seen at
thebinding level share the same subset of accessors:</p>
<ul>
<li><code>name</code>: returns the node name</li>
<li><code>type</code>: returns a string indicating the node type</li>
<li><code>content</code>: returns the content of the node, it is based
onxmlNodeGetContent() and hence is recursive.</li>
<li><code>parent</code>, <code>children</code>,
<code>last</code>,<code>next</code>, <code>prev</code>,
<code>doc</code>,<code>properties</code>: pointing to the associated
element in the tree,those may return None in case no such link
exists.</li>
</ul>
<p>Also note the need to explicitly deallocate documents with freeDoc()
.Reference counting for libxml2 trees would need quite a lot of work
tofunction properly, and rather than risk memory leaks if not
implementedcorrectly it sounds safer to have an explicit function to free a
tree. Thewrapper python objects like doc, root or child are them
automatically garbagecollected.</p>
<h3>validate.py:</h3>
<p>This test check the validation interfaces and redirection of
errormessages:</p>
<pre>import libxml2
#deactivate error messages from the validation
def noerr(ctx, str):
pass
libxml2.registerErrorHandler(noerr, None)
ctxt = libxml2.createFileParserCtxt("invalid.xml")
ctxt.validate(1)
ctxt.parseDocument()
doc = ctxt.doc()
valid = ctxt.isValid()
doc.freeDoc()
if valid != 0:
print "validity check failed"</pre>
<p>The first thing to notice is the call to registerErrorHandler(), itdefines
a new error handler global to the library. It is used to avoid seeingthe
error messages when trying to validate the invalid document.</p>
<p>The main interest of that test is the creation of a parser context
withcreateFileParserCtxt() and how the behaviour can be changed before
callingparseDocument() . Similarly the informations resulting from the
parsing phaseare also available using context methods.</p>
<p>Contexts like nodes are defined as class and the libxml2 wrappers maps
theC function interfaces in terms of objects method as much as possible.
Thebest to get a complete view of what methods are supported is to look at
thelibxml2.py module containing all the wrappers.</p>
<h3>push.py:</h3>
<p>This test show how to activate the push parser interface:</p>
<pre>import libxml2
ctxt = libxml2.createPushParser(None, "&lt;foo", 4, "test.xml")
ctxt.parseChunk("/&gt;", 2, 1)
doc = ctxt.doc()
doc.freeDoc()</pre>
<p>The context is created with a special call based on
thexmlCreatePushParser() from the C library. The first argument is an
optionalSAX callback object, then the initial set of data, the length and the
name ofthe resource in case URI-References need to be computed by the
parser.</p>
<p>Then the data are pushed using the parseChunk() method, the last
callsetting the third argument terminate to 1.</p>
<h3>pushSAX.py:</h3>
<p>this test show the use of the event based parsing interfaces. In this
casethe parser does not build a document, but provides callback information
asthe parser makes progresses analyzing the data being provided:</p>
<pre>import libxml2
log = ""
class callback:
def startDocument(self):
global log
log = log + "startDocument:"
def endDocument(self):
global log
log = log + "endDocument:"
def startElement(self, tag, attrs):
global log
log = log + "startElement %s %s:" % (tag, attrs)
def endElement(self, tag):
global log
log = log + "endElement %s:" % (tag)
def characters(self, data):
global log
log = log + "characters: %s:" % (data)
def warning(self, msg):
global log
log = log + "warning: %s:" % (msg)
def error(self, msg):
global log
log = log + "error: %s:" % (msg)
def fatalError(self, msg):
global log
log = log + "fatalError: %s:" % (msg)
handler = callback()
ctxt = libxml2.createPushParser(handler, "&lt;foo", 4, "test.xml")
chunk = " url='tst'&gt;b"
ctxt.parseChunk(chunk, len(chunk), 0)
chunk = "ar&lt;/foo&gt;"
ctxt.parseChunk(chunk, len(chunk), 1)
reference = "startDocument:startElement foo {'url': 'tst'}:" + \
"characters: bar:endElement foo:endDocument:"
if log != reference:
print "Error got: %s" % log
print "Expected: %s" % reference</pre>
<p>The key object in that test is the handler, it provides a number of
entrypoints which can be called by the parser as it makes progresses to
indicatethe information set obtained. The full set of callback is larger than
whatthe callback class in that specific example implements (see the
SAXdefinition for a complete list). The wrapper will only call those supplied
bythe object when activated. The startElement receives the names of the
elementand a dictionary containing the attributes carried by this element.</p>
<p>Also note that the reference string generated from the callback shows
asingle character call even though the string "bar" is passed to the
parserfrom 2 different call to parseChunk()</p>
<h3>xpath.py:</h3>
<p>This is a basic test of XPath wrappers support</p>
<pre>import libxml2
doc = libxml2.parseFile("tst.xml")
ctxt = doc.xpathNewContext()
res = ctxt.xpathEval("//*")
if len(res) != 2:
print "xpath query: wrong node set size"
sys.exit(1)
if res[0].name != "doc" or res[1].name != "foo":
print "xpath query: wrong node set value"
sys.exit(1)
doc.freeDoc()
ctxt.xpathFreeContext()</pre>
<p>This test parses a file, then create an XPath context to evaluate
XPathexpression on it. The xpathEval() method execute an XPath query and
returnsthe result mapped in a Python way. String and numbers are natively
converted,and node sets are returned as a tuple of libxml2 Python nodes
wrappers. Likethe document, the XPath context need to be freed explicitly,
also not thatthe result of the XPath query may point back to the document
tree and hencethe document must be freed after the result of the query is
used.</p>
<h3>xpathext.py:</h3>
<p>This test shows how to extend the XPath engine with functions written
inpython:</p>
<pre>import libxml2
def foo(ctx, x):
return x + 1
doc = libxml2.parseFile("tst.xml")
ctxt = doc.xpathNewContext()
libxml2.registerXPathFunction(ctxt._o, "foo", None, foo)
res = ctxt.xpathEval("foo(1)")
if res != 2:
print "xpath extension failure"
doc.freeDoc()
ctxt.xpathFreeContext()</pre>
<p>Note how the extension function is registered with the context (but
thatpart is not yet finalized, this may change slightly in the future).</p>
<h3>tstxpath.py:</h3>
<p>This test is similar to the previous one but shows how the
extensionfunction can access the XPath evaluation context:</p>
<pre>def foo(ctx, x):
global called
#
# test that access to the XPath evaluation contexts
#
pctxt = libxml2.xpathParserContext(_obj=ctx)
ctxt = pctxt.context()
called = ctxt.function()
return x + 1</pre>
<p>All the interfaces around the XPath parser(or rather evaluation)
contextare not finalized, but it should be sufficient to do contextual work
at theevaluation point.</p>
<h3>Memory debugging:</h3>
<p>last but not least, all tests starts with the following prologue:</p>
<pre>#memory debug specific
libxml2.debugMemory(1)</pre>
<p>and ends with the following epilogue:</p>
<pre>#memory debug specific
libxml2.cleanupParser()
if libxml2.debugMemory(1) == 0:
print "OK"
else:
print "Memory leak %d bytes" % (libxml2.debugMemory(1))
libxml2.dumpMemory()</pre>
<p>Those activate the memory debugging interface of libxml2 where
allallocated block in the library are tracked. The prologue then cleans up
thelibrary state and checks that all allocated memory has been freed. If not
itcalls dumpMemory() which saves that list in a <code>.memdump</code>file.</p>
<h2><a name="architecture">libxml2 architecture</a></h2>
<p>Libxml2 is made of multiple components; some of them are optional, andmost
of the block interfaces are public. The main components are:</p>
<ul>
<li>an Input/Output layer</li>
<li>FTP and HTTP client layers (optional)</li>
<li>an Internationalization layer managing the encodings support</li>
<li>a URI module</li>
<li>the XML parser and its basic SAX interface</li>
<li>an HTML parser using the same SAX interface (optional)</li>
<li>a SAX tree module to build an in-memory DOM representation</li>
<li>a tree module to manipulate the DOM representation</li>
<li>a validation module using the DOM representation (optional)</li>
<li>an XPath module for global lookup in a DOM representation(optional)</li>
<li>a debug module (optional)</li>
</ul>
<p>Graphically this gives the following:</p>
<p><img src="libxml.gif" alt="a graphical view of the various"></p>
<p></p>
<h2><a name="tree">The tree output</a></h2>
<p>The parser returns a tree built during the document analysis. The
valuereturned is an <strong>xmlDocPtr</strong>(i.e., a pointer to
an<strong>xmlDoc</strong>structure). This structure contains information
suchas the file name, the document type, and a
<strong>children</strong>pointerwhich is the root of the document (or more
exactly the first child under theroot which is the document). The tree is
made of <strong>xmlNode</strong>s,chained in double-linked lists of siblings
and with a children&lt;-&gt;parentrelationship. An xmlNode can also carry
properties (a chain of xmlAttrstructures). An attribute may have a value
which is a list of TEXT orENTITY_REF nodes.</p>
<p>Here is an example (erroneous with respect to the XML spec since
thereshould be only one ELEMENT under the root):</p>
<p><img src="structure.gif" alt=" structure.gif "></p>
<p>In the source package there is a small program (not installed by
default)called <strong>xmllint</strong>which parses XML files given as
argument andprints them back as parsed. This is useful for detecting errors
both in XMLcode and in the XML parser itself. It has an option
<strong>--debug</strong>which prints the actual in-memory structure of the
document; here is theresult with the <a href="#example">example</a>given
before:</p>
<pre>DOCUMENT
version=1.0
standalone=true
ELEMENT EXAMPLE
ATTRIBUTE prop1
TEXT
content=gnome is great
ATTRIBUTE prop2
ENTITY_REF
TEXT
content= linux too
ELEMENT head
ELEMENT title
TEXT
content=Welcome to Gnome
ELEMENT chapter
ELEMENT title
TEXT
content=The Linux adventure
ELEMENT p
TEXT
content=bla bla bla ...
ELEMENT image
ATTRIBUTE href
TEXT
content=linus.gif
ELEMENT p
TEXT
content=...</pre>
<p>This should be useful for learning the internal representation model.</p>
<h2><a name="interface">The SAX interface</a></h2>
<p>Sometimes the DOM tree output is just too large to fit reasonably
intomemory. In that case (and if you don't expect to save back the XML
documentloaded using libxml), it's better to use the SAX interface of libxml.
SAX isa <strong>callback-based interface</strong>to the parser. Before
parsing,the application layer registers a customized set of callbacks which
arecalled by the library as it progresses through the XML input.</p>
<p>To get more detailed step-by-step guidance on using the SAX interface
oflibxml, see the <a
href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nicedocumentation</a>.written
by <a href="mailto:james@daa.com.au">JamesHenstridge</a>.</p>
<p>You can debug the SAX behaviour by using the
<strong>testSAX</strong>program located in the gnome-xml module (it's usually
not shipped in thebinary packages of libxml, but you can find it in the tar
sourcedistribution). Here is the sequence of callbacks that would be reported
bytestSAX when parsing the example XML document shown earlier:</p>
<pre>SAX.setDocumentLocator()
SAX.startDocument()
SAX.getEntity(amp)
SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
SAX.characters( , 3)
SAX.startElement(head)
SAX.characters( , 4)
SAX.startElement(title)
SAX.characters(Welcome to Gnome, 16)
SAX.endElement(title)
SAX.characters( , 3)
SAX.endElement(head)
SAX.characters( , 3)
SAX.startElement(chapter)
SAX.characters( , 4)
SAX.startElement(title)
SAX.characters(The Linux adventure, 19)
SAX.endElement(title)
SAX.characters( , 4)
SAX.startElement(p)
SAX.characters(bla bla bla ..., 15)
SAX.endElement(p)
SAX.characters( , 4)
SAX.startElement(image, href='linus.gif')
SAX.endElement(image)
SAX.characters( , 4)
SAX.startElement(p)
SAX.characters(..., 3)
SAX.endElement(p)
SAX.characters( , 3)
SAX.endElement(chapter)
SAX.characters( , 1)
SAX.endElement(EXAMPLE)
SAX.endDocument()</pre>
<p>Most of the other interfaces of libxml2 are based on the DOM
tree-buildingfacility, so nearly everything up to the end of this document
presupposes theuse of the standard DOM tree build. Note that the DOM tree
itself is built bya set of registered default callbacks, without internal
specificinterface.</p>
<h2><a name="Validation">Validation &amp; DTDs</a></h2>
<p>Table of Content:</p>
<ol>
<li><a href="#General5">General overview</a></li>
<li><a href="#definition">The definition</a></li>
<li><a href="#Simple">Simple rules</a>
<ol>
<li><a href="#reference">How to reference a DTD from a document</a></li>
<li><a href="#Declaring">Declaring elements</a></li>
<li><a href="#Declaring1">Declaring attributes</a></li>
</ol>
</li>
<li><a href="#Some">Some examples</a></li>
<li><a href="#validate">How to validate</a></li>
<li><a href="#Other">Other resources</a></li>
</ol>
<h3><a name="General5">General overview</a></h3>
<p>Well what is validation and what is a DTD ?</p>
<p>DTD is the acronym for Document Type Definition. This is a description
ofthe content for a family of XML files. This is part of the XML
1.0specification, and allows one to describe and verify that a given
documentinstance conforms to the set of rules detailing its structure and
content.</p>
<p>Validation is the process of checking a document against a DTD
(moregenerally against a set of construction rules).</p>
<p>The validation process and building DTDs are the two most difficult
partsof the XML life cycle. Briefly a DTD defines all the possible elements
to befound within your document, what is the formal shape of your document
tree(by defining the allowed content of an element; either text, a
regularexpression for the allowed list of children, or mixed content i.e.
both textand children). The DTD also defines the valid attributes for all
elements andthe types of those attributes.</p>
<h3><a name="definition1">The definition</a></h3>
<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a>(<a
href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version
ofRev1</a>):</p>
<ul>
<li><a
href="http://www.w3.org/TR/REC-xml#elemdecls">Declaringelements</a></li>
<li><a
href="http://www.w3.org/TR/REC-xml#attdecls">Declaringattributes</a></li>
</ul>
<p>(unfortunately) all this is inherited from the SGML world, the syntax
isancient...</p>
<h3><a name="Simple1">Simple rules</a></h3>
<p>Writing DTDs can be done in many ways. The rules to build them if you
needsomething permanent or something which can evolve over time can be
radicallydifferent. Really complex DTDs like DocBook ones are flexible but
quiteharder to design. I will just focus on DTDs for a formats with a fixed
simplestructure. It is just a set of basic rules, and definitely not
exhaustive norusable for complex DTD design.</p>
<h4><a name="reference1">How to reference a DTD from a document</a>:</h4>
<p>Assuming the top element of the document is <code>spec</code>and the dtdis
placed in the file <code>mydtd</code>in the subdirectory<code>dtds</code>of
the directory from where the document were loaded:</p>
<p><code>&lt;!DOCTYPE spec SYSTEM "dtds/mydtd"&gt;</code></p>
<p>Notes:</p>
<ul>
<li>The system string is actually an URI-Reference (as defined in <a
href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use
afull URL string indicating the location of your DTD on the Web. This is
areally good thing to do if you want others to validate your
document.</li>
<li>It is also possible to associate a <code>PUBLIC</code>identifier
(amagic string) so that the DTD is looked up in catalogs on the client
sidewithout having to locate it on the web.</li>
<li>A DTD contains a set of element and attribute declarations, but
theydon't define what the root of the document should be. This is
explicitlytold to the parser/validator as the first element of
the<code>DOCTYPE</code>declaration.</li>
</ul>
<h4><a name="Declaring2">Declaring elements</a>:</h4>
<p>The following declares an element <code>spec</code>:</p>
<p><code>&lt;!ELEMENT spec (front, body, back?)&gt;</code></p>
<p>It also expresses that the spec element contains one
<code>front</code>,one <code>body</code>and one optional
<code>back</code>children elements inthis order. The declaration of one
element of the structure and its contentare done in a single declaration.
Similarly the following declares<code>div1</code>elements:</p>
<p><code>&lt;!ELEMENT div1 (head, (p | list | note)*, div2?)&gt;</code></p>
<p>which means div1 contains one <code>head</code>then a series of
optional<code>p</code>, <code>list</code>s and <code>note</code>s and then
anoptional <code>div2</code>. And last but not least an element can
containtext:</p>
<p><code>&lt;!ELEMENT b (#PCDATA)&gt;</code></p>
<p><code>b</code>contains text or being of mixed content (text and elementsin
no particular order):</p>
<p><code>&lt;!ELEMENT p (#PCDATA|a|ul|b|i|em)*&gt;</code></p>
<p><code>p </code>can contain text or <code>a</code>,
<code>ul</code>,<code>b</code>, <code>i </code>or <code>em</code>elements in
no particularorder.</p>
<h4><a name="Declaring1">Declaring attributes</a>:</h4>
<p>Again the attributes declaration includes their content definition:</p>
<p><code>&lt;!ATTLIST termdef name CDATA #IMPLIED&gt;</code></p>
<p>means that the element <code>termdef</code>can have a
<code>name</code>attribute containing text (<code>CDATA</code>) and which is
optional(<code>#IMPLIED</code>). The attribute value can also be defined
within aset:</p>
<p><code>&lt;!ATTLIST list type
(bullets|ordered|glossary)"ordered"&gt;</code></p>
<p>means <code>list</code>element have a <code>type</code>attribute with
3allowed values "bullets", "ordered" or "glossary" and which default
to"ordered" if the attribute is not explicitly specified.</p>
<p>The content type of an attribute can be text
(<code>CDATA</code>),anchor/reference/references(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>),
entity(ies)(<code>ENTITY</code>/<code>ENTITIES</code>) or
name(s)(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines
that a<code>chapter</code>element can have an optional
<code>id</code>attributeof type <code>ID</code>, usable for reference from
attribute of typeIDREF:</p>
<p><code>&lt;!ATTLIST chapter id ID #IMPLIED&gt;</code></p>
<p>The last value of an attribute definition can be
<code>#REQUIRED</code>meaning that the attribute has to be given,
<code>#IMPLIED</code>meaning that it is optional, or the default value
(possibly prefixed by<code>#FIXED</code>if it is the only allowed).</p>
<p>Notes:</p>
<ul>
<li>Usually the attributes pertaining to a given element are declared in
asingle expression, but it is just a convention adopted by a lot of
DTDwriters:
<pre>&lt;!ATTLIST termdef
id ID #REQUIRED
name CDATA #IMPLIED&gt;</pre>
<p>The previous construct defines both
<code>id</code>and<code>name</code>attributes for the element
<code>termdef</code>.</p>
</li>
</ul>
<h3><a name="Some1">Some examples</a></h3>
<p>The directory <code>test/valid/dtds/</code>in the libxml2
distributioncontains some complex DTD examples. The example in the
file<code>test/valid/dia.xml</code>shows an XML file where the simple DTD
isdirectly included within the document.</p>
<h3><a name="validate1">How to validate</a></h3>
<p>The simplest way is to use the xmllint program included with libxml.
The<code>--valid</code>option turns-on validation of the files given as
input.For example the following validates a copy of the first revision of the
XML1.0 specification:</p>
<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p>
<p>the -- noout is used to disable output of the resulting tree.</p>
<p>The <code>--dtdvalid dtd</code>allows validation of the document(s)against
a given DTD.</p>
<p>Libxml2 exports an API to handle DTDs and validation, check the <a
href="http://xmlsoft.org/html/libxml-valid.html">associateddescription</a>.</p>
<h3><a name="Other1">Other resources</a></h3>
<p>DTDs are as old as SGML. So there may be a number of examples on-line,
Iwill just list one for now, others pointers welcome:</p>
<ul>
<li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li>
</ul>
<p>I suggest looking at the examples found under test/valid/dtd and any ofthe
large number of books available on XML. The dia example in test/validshould
be both simple and complete enough to allow you to build your own.</p>
<p></p>
<h2><a name="Memory">Memory Management</a></h2>
<p>Table of Content:</p>
<ol>
<li><a href="#General3">General overview</a></li>
<li><a href="#setting">Setting libxml2 set of memory routines</a></li>
<li><a href="#cleanup">Cleaning up after parsing</a></li>
<li><a href="#Debugging">Debugging routines</a></li>
<li><a href="#General4">General memory requirements</a></li>
</ol>
<h3><a name="General3">General overview</a></h3>
<p>The module <code><a
href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>provides
the interfaces to the libxml2 memory system:</p>
<ul>
<li>libxml2 does not use the libc memory allocator directly but
xmlFree(),xmlMalloc() and xmlRealloc()</li>
<li>those routines can be reallocated to a specific set of routine,
bydefault the libc ones i.e. free(), malloc() and realloc()</li>
<li>the xmlmemory.c module includes a set of debugging routine</li>
</ul>
<h3><a name="setting">Setting libxml2 set of memory routines</a></h3>
<p>It is sometimes useful to not use the default memory allocator, either
fordebugging, analysis or to implement a specific behaviour on memory
management(like on embedded systems). Two function calls are available to do
so:</p>
<ul>
<li><a
href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet()</a>which
return the current set of functions in use by the parser</li>
<li><a
href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>which
allow to set up a new set of memory allocation functions</li>
</ul>
<p>Of course a call to xmlMemSetup() should probably be done before
callingany other libxml2 routines (unless you are sure your allocations
routines arecompatibles).</p>
<h3><a name="cleanup">Cleaning up after parsing</a></h3>
<p>Libxml2 is not stateless, there is a few set of memory structures
needingallocation before the parser is fully functional (some encoding
structuresfor example). This also mean that once parsing is finished there is
a tinyamount of memory (a few hundred bytes) which can be recollected if you
don'treuse the parser immediately:</p>
<ul>
<li><a
href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser()</a>is
a centralized routine to free the parsing states. Note that itwon't
deallocate any produced tree if any (use the xmlFreeDoc() andrelated
routines for this).</li>
<li><a
href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser()</a>is
the dual routine allowing to preallocate the parsing statewhich can be
useful for example to avoid initialization reentrancyproblems when using
libxml2 in multithreaded applications</li>
</ul>
<p>Generally xmlCleanupParser() is safe, if needed the state will be
rebuildat the next invocation of parser routines, but be careful of the
consequencesin multithreaded applications.</p>
<h3><a name="Debugging">Debugging routines</a></h3>
<p>When configured using --with-mem-debug flag (off by default), libxml2
usesa set of memory allocation debugging routines keeping track of all
allocatedblocks and the location in the code where the routine was called. A
couple ofother debugging routines allow to dump the memory allocated infos to
a fileor call a specific routine when a given block number is allocated:</p>
<ul>
<li><a
href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a><a
href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>and
<a
href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>are
the memory debugging replacement allocation routines</li>
<li><a
href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump()</a>dumps
all the informations about the allocated memory block leftsin the
<code>.memdump</code>file</li>
</ul>
<p>When developing libxml2 memory debug is enabled, the tests programs
callxmlMemoryDump () and the "make test" regression tests will check for
anymemory leak during the full regression test sequence, this helps a
lotensuring that libxml2 does not leak memory and bullet proof
memoryallocations use (some libc implementations are known to be far too
permissiveresulting in major portability problems!).</p>
<p>If the .memdump reports a leak, it displays the allocation function
andalso tries to give some informations about the content and structure of
theallocated blocks left. This is sufficient in most cases to find the
culprit,but not always. Assuming the allocation problem is reproducible, it
ispossible to find more easily:</p>
<ol>
<li>write down the block number xxxx not allocated</li>
<li>export the environment variable XML_MEM_BREAKPOINT=xxxx , the
easiestwhen using GDB is to simply give the command
<p><code>set environment XML_MEM_BREAKPOINT xxxx</code></p>
<p>before running the program.</p>
</li>
<li>run the program under a debugger and set a breakpoint
onxmlMallocBreakpoint() a specific function called when this precise
blockis allocated</li>
<li>when the breakpoint is reached you can then do a fine analysis of
theallocation an step to see the condition resulting in the
missingdeallocation.</li>
</ol>
<p>I used to use a commercial tool to debug libxml2 memory problems but
afternoticing that it was not detecting memory leaks that simple mechanism
wasused and proved extremely efficient until now. Lately I have also used <a
href="http://developer.kde.org/~sewardj/">valgrind</a>with quite somesuccess,
it is tied to the i386 architecture since it works by emulating theprocessor
and instruction set, it is slow but extremely efficient, i.e. itspot memory
usage errors in a very precise way.</p>
<h3><a name="General4">General memory requirements</a></h3>
<p>How much libxml2 memory require ? It's hard to tell in average it
dependsof a number of things:</p>
<ul>
<li>the parser itself should work in a fixed amount of memory, except
forinformation maintained about the stacks of names and entities
locations.The I/O and encoding handlers will probably account for a few
KBytes.This is true for both the XML and HTML parser (though the HTML
parserneed more state).</li>
<li>If you are generating the DOM tree then memory requirements will
grownearly linear with the size of the data. In general for a
balancedtextual document the internal memory requirement is about 4 times
thesize of the UTF8 serialization of this document (example the
XML-1.0recommendation is a bit more of 150KBytes and takes 650KBytes of
mainmemory when parsed). Validation will add a amount of memory required
formaintaining the external Dtd state which should be linear with
thecomplexity of the content model defined by the Dtd</li>
<li>If you need to work with fixed memory requirements or don't need
thefull DOM tree then using the <a
href="xmlreader.html">xmlReaderinterface</a>is probably the best way to
proceed, it still allows tovalidate or operate on subset of the tree if
needed.</li>
<li>If you don't care about the advanced features of libxml2
likevalidation, DOM, XPath or XPointer, don't use entities, need to work
withfixed memory requirements, and try to get the fastest parsing
possiblethen the SAX interface should be used, but it has known
restrictions.</li>
</ul>
<p></p>
<h2><a name="Encodings">Encodings support</a></h2>
<p>If you are not really familiar with Internationalization (usual shortcutis
I18N) , Unicode, characters and glyphs, I suggest you read a <a
href="http://www.tbray.org/ongoing/When/200x/2003/04/06/Unicode">presentation</a>by
Tim Bray on Unicode and why you should care about it.</p>
<p>If you don't understand why <b>it does not make sense to have a
stringwithout knowing what encoding it uses</b>, then as Joel Spolsky said <a
href="http://www.joelonsoftware.com/articles/Unicode.html">please do notwrite
another line of code until you finish reading that article.</a>. It isa
prerequisite to understand this page, and avoid a lot of problems
withlibxml2, XML or text processing in general.</p>
<p>Table of Content:</p>
<ol>
<li><a href="encoding.html#What">What does internationalization supportmean
?</a></li>
<li><a href="encoding.html#internal">The internal encoding, how
andwhy</a></li>
<li><a href="encoding.html#implemente">How is it implemented ?</a></li>
<li><a href="encoding.html#Default">Default supported encodings</a></li>
<li><a href="encoding.html#extend">How to extend the
existingsupport</a></li>
</ol>
<h3><a name="What">What does internationalization support mean ?</a></h3>
<p>XML was designed from the start to allow the support of any character
setby using Unicode. Any conformant XML parser has to support the UTF-8
andUTF-16 default encodings which can both express the full unicode ranges.
UTF8is a variable length encoding whose greatest points are to reuse the
sameencoding for ASCII and to save space for Western encodings, but it is a
bitmore complex to handle in practice. UTF-16 use 2 bytes per character
(andsometimes combines two pairs), it makes implementation easier, but looks
abit overkill for Western languages encoding. Moreover the XML
specificationallows the document to be encoded in other encodings at the
condition thatthey are clearly labeled as such. For example the following is
a wellformedXML document encoded in ISO-8859-1 and using accentuated letters
that weFrench like for both markup and content:</p>
<pre>&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
&lt;très&gt;là&lt;/très&gt;</pre>
<p>Having internationalization support in libxml2 means the following:</p>
<ul>
<li>the document is properly parsed</li>
<li>informations about it's encoding are saved</li>
<li>it can be modified</li>
<li>it can be saved in its original encoding</li>
<li>it can also be saved in another encoding supported by libxml2
(forexample straight UTF8 or even an ASCII form)</li>
</ul>
<p>Another very important point is that the whole libxml2 API, with
theexception of a few routines to read with a specific encoding or save to
aspecific encoding, is completely agnostic about the original encoding of
thedocument.</p>
<p>It should be noted too that the HTML parser embedded in libxml2 now
obeythe same rules too, the following document will be (as of 2.2.2) handled
inan internationalized fashion by libxml2 too:</p>
<pre>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
"http://www.w3.org/TR/REC-html40/loose.dtd"&gt;
&lt;html lang="fr"&gt;
&lt;head&gt;
&lt;META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"&gt;
&lt;/head&gt;
&lt;body&gt;
&lt;p&gt;W3C crée des standards pour le Web.&lt;/body&gt;
&lt;/html&gt;</pre>
<h3><a name="internal">The internal encoding, how and why</a></h3>
<p>One of the core decisions was to force all documents to be converted to
adefault internal encoding, and that encoding to be UTF-8, here are
therationales for those choices:</p>
<ul>
<li>keeping the native encoding in the internal form would force the
libxmlusers (or the code associated) to be fully aware of the encoding of
theoriginal document, for examples when adding a text node to a
document,the content would have to be provided in the document encoding,
i.e. theclient code would have to check it before hand, make sure it's
conformantto the encoding, etc ... Very hard in practice, though in some
specificcases this may make sense.</li>
<li>the second decision was which encoding. From the XML spec only UTF8
andUTF16 really makes sense as being the two only encodings for which
thereis mandatory support. UCS-4 (32 bits fixed size encoding) could
beconsidered an intelligent choice too since it's a direct Unicode
mappingsupport. I selected UTF-8 on the basis of efficiency and
compatibilitywith surrounding software:
<ul>
<li>UTF-8 while a bit more complex to convert from/to (i.e.
slightlymore costly to import and export CPU wise) is also far more
compactthan UTF-16 (and UCS-4) for a majority of the documents I see
it usedfor right now (RPM RDF catalogs, advogato data, various
configurationfile formats, etc.) and the key point for today's
computerarchitecture is efficient uses of caches. If one nearly
double thememory requirement to store the same amount of data, this
will trashcaches (main memory/external caches/internal caches) and my
take isthat this harms the system far more than the CPU requirements
neededfor the conversion to UTF-8</li>
<li>Most of libxml2 version 1 users were using it with straight
ASCIImost of the time, doing the conversion with an internal
encodingrequiring all their code to be rewritten was a serious
show-stopperfor using UTF-16 or UCS-4.</li>
<li>UTF-8 is being used as the de-facto internal encoding standard
forrelated code like the <a
href="http://www.pango.org/">pango</a>upcoming Gnome text widget, and
a lot of Unix code (yet another placewhere Unix programmer base takes
a different approach from Microsoft- they are using UTF-16)</li>
</ul>
</li>
</ul>
<p>What does this mean in practice for the libxml2 user:</p>
<ul>
<li>xmlChar, the libxml2 data type is a byte, those bytes must be
assembledas UTF-8 valid strings. The proper way to terminate an xmlChar *
stringis simply to append 0 byte, as usual.</li>
<li>One just need to make sure that when using chars outside the ASCII
set,the values has been properly converted to UTF-8</li>
</ul>
<h3><a name="implemente">How is it implemented ?</a></h3>
<p>Let's describe how all this works within libxml, basically the
I18N(internationalization) support get triggered only during I/O operation,
i.e.when reading a document or saving one. Let's look first at the
readingsequence:</p>
<ol>
<li>when a document is processed, we usually don't know the encoding,
asimple heuristic allows to detect UTF-16 and UCS-4 from encodings
wherethe ASCII range (0-0x7F) maps with ASCII</li>
<li>the xml declaration if available is parsed, including the
encodingdeclaration. At that point, if the autodetected encoding is
differentfrom the one declared a call to xmlSwitchEncoding() is
issued.</li>
<li>If there is no encoding declaration, then the input has to be in
eitherUTF-8 or UTF-16, if it is not then at some point when processing
theinput, the converter/checker of UTF-8 form will raise an encoding
error.You may end-up with a garbled document, or no document at all !
Example:
<pre>~/XML -&gt; ./xmllint err.xml
err.xml:1: error: Input is not proper UTF-8, indicate encoding !
&lt;très&gt;là&lt;/très&gt;
^
err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C
&lt;très&gt;là&lt;/très&gt;
^</pre>
</li>
<li>xmlSwitchEncoding() does an encoding name lookup, canonicalize it,
andthen search the default registered encoding converters for that
encoding.If it's not within the default set and iconv() support has been
compiledit, it will ask iconv for such an encoder. If this fails then the
parserwill report an error and stops processing:
<pre>~/XML -&gt; ./xmllint err2.xml
err2.xml:1: error: Unsupported encoding UnsupportedEnc
&lt;?xml version="1.0" encoding="UnsupportedEnc"?&gt;
^</pre>
</li>
<li>From that point the encoder processes progressively the input (it
isplugged as a front-end to the I/O module) for that entity. It
capturesand converts on-the-fly the document to be parsed to UTF-8. The
parseritself just does UTF-8 checking of this input and process
ittransparently. The only difference is that the encoding information
hasbeen added to the parsing context (more precisely to the
inputcorresponding to this entity).</li>
<li>The result (when using DOM) is an internal form completely in UTF-8with
just an encoding information on the document node.</li>
</ol>
<p>Ok then what happens when saving the document (assuming youcollected/built
an xmlDoc DOM like structure) ? It depends on the functioncalled,
xmlSaveFile() will just try to save in the original encoding,
whilexmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a
givenencoding:</p>
<ol>
<li>if no encoding is given, libxml2 will look for an encoding
valueassociated to the document and if it exists will try to save to
thatencoding,
<p>otherwise everything is written in the internal form, i.e. UTF-8</p>
</li>
<li>so if an encoding was specified, either at the API level or on
thedocument, libxml2 will again canonicalize the encoding name, lookup
for aconverter in the registered set or through iconv. If not found
thefunction will return an error code</li>
<li>the converter is placed before the I/O buffer layer, as another kind
ofbuffer, then libxml2 will simply push the UTF-8 serialization to
throughthat buffer, which will then progressively be converted and pushed
ontothe I/O layer.</li>
<li>It is possible that the converter code fails on some input, for
exampletrying to push an UTF-8 encoded Chinese character through the
UTF-8 toISO-8859-1 converter won't work. Since the encoders are
progressive theywill just report the error and the number of bytes
converted, at thatpoint libxml2 will decode the offending character,
remove it from thebuffer and replace it with the associated charRef
encoding &amp;#123; andresume the conversion. This guarantees that any
document will be savedwithout losses (except for markup names where this
is not legal, this isa problem in the current version, in practice avoid
using non-asciicharacters for tag or attribute names). A special "ascii"
encoding nameis used to save documents to a pure ascii form can be used
whenportability is really crucial</li>
</ol>
<p>Here are a few examples based on the same test document:</p>
<pre>~/XML -&gt; ./xmllint isolat1
&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
&lt;très&gt;là&lt;/très&gt;
~/XML -&gt; ./xmllint --encode UTF-8 isolat1
&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;très&gt;là  &lt;/très&gt;
~/XML -&gt; </pre>
<p>The same processing is applied (and reuse most of the code) for HTML
I18Nprocessing. Looking up and modifying the content encoding is a bit
moredifficult since it is located in a &lt;meta&gt; tag under the
&lt;head&gt;,so a couple of functions htmlGetMetaEncoding() and
htmlSetMetaEncoding() havebeen provided. The parser also attempts to switch
encoding on the fly whendetecting such a tag on input. Except for that the
processing is the same(and again reuses the same code).</p>
<h3><a name="Default">Default supported encodings</a></h3>
<p>libxml2 has a set of default converters for the following
encodings(located in encoding.c):</p>
<ol>
<li>UTF-8 is supported by default (null handlers)</li>
<li>UTF-16, both little and big endian</li>
<li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li>
<li>ASCII, useful mostly for saving</li>
<li>HTML, a specific handler for the conversion of UTF-8 to ASCII with
HTMLpredefined entities like &amp;copy; for the Copyright sign.</li>
</ol>
<p>More over when compiled on an Unix platform with iconv support the fullset
of encodings supported by iconv can be instantly be used by libxml. On alinux
machine with glibc-2.1 the list of supported encodings and aliases fill3 full
pages, and include UCS-4, the full set of ISO-Latin encodings, and thevarious
Japanese ones.</p>
<p>To convert from the UTF-8 values returned from the API to another
encodingthen it is possible to use the function provided from <a
href="html/libxml-encoding.html">the encoding module</a>like <a
href="html/libxml-encoding.html#UTF8Toisolat1">UTF8Toisolat1</a>, or use
thePOSIX <a
href="http://www.opengroup.org/onlinepubs/009695399/functions/iconv.html">iconv()</a>API
directly.</p>
<h4>Encoding aliases</h4>
<p>From 2.2.3, libxml2 has support to register encoding names aliases.
Thegoal is to be able to parse document whose encoding is supported but
wherethe name differs (for example from the default set of names accepted
byiconv). The following functions allow to register and handle new aliases
forexisting encodings. Once registered libxml2 will automatically lookup
thealiases when handling a document:</p>
<ul>
<li>int xmlAddEncodingAlias(const char *name, const char *alias);</li>
<li>int xmlDelEncodingAlias(const char *alias);</li>
<li>const char * xmlGetEncodingAlias(const char *alias);</li>
<li>void xmlCleanupEncodingAliases(void);</li>
</ul>
<h3><a name="extend">How to extend the existing support</a></h3>
<p>Well adding support for new encoding, or overriding one of the
encoders(assuming it is buggy) should not be hard, just write input and
outputconversion routines to/from UTF-8, and register them
usingxmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will
becalled automatically if the parser(s) encounter such an encoding
name(register it uppercase, this will help). The description of the
encoders,their arguments and expected return values are described in the
encoding.hheader.</p>
<h2><a name="IO">I/O Interfaces</a></h2>
<p>Table of Content:</p>
<ol>
<li><a href="#General1">General overview</a></li>
<li><a href="#basic">The basic buffer type</a></li>
<li><a href="#Input">Input I/O handlers</a></li>
<li><a href="#Output">Output I/O handlers</a></li>
<li><a href="#entities">The entities loader</a></li>
<li><a href="#Example2">Example of customized I/O</a></li>
</ol>
<h3><a name="General1">General overview</a></h3>
<p>The module <code><a
href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code>providesthe
interfaces to the libxml2 I/O system. This consists of 4 main parts:</p>
<ul>
<li>Entities loader, this is a routine which tries to fetch the
entities(files) based on their PUBLIC and SYSTEM identifiers. The default
loaderdon't look at the public identifier since libxml2 do not maintain
acatalog. You can redefine you own entity loader by
using<code>xmlGetExternalEntityLoader()</code>and<code>xmlSetExternalEntityLoader()</code>.
<a href="#entities">Check theexample</a>.</li>
<li>Input I/O buffers which are a commodity structure used by the
parser(s)input layer to handle fetching the informations to feed the
parser. Thisprovides buffering and is also a placeholder where the
encodingconverters to UTF8 are piggy-backed.</li>
<li>Output I/O buffers are similar to the Input ones and fulfill
similartask but when generating a serialization from a tree.</li>
<li>A mechanism to register sets of I/O callbacks and associate them
withspecific naming schemes like the protocol part of the URIs.
<p>This affect the default I/O operations and allows to use specific
I/Ohandlers for certain names.</p>
</li>
</ul>
<p>The general mechanism used when loading http://rpmfind.net/xml.html
forexample in the HTML parser is the following:</p>
<ol>
<li>The default entity loader calls
<code>xmlNewInputFromFile()</code>withthe parsing context and the URI
string.</li>
<li>the URI string is checked against the existing registered handlersusing
their match() callback function, if the HTTP module was compiledin, it is
registered and its match() function will succeeds</li>
<li>the open() function of the handler is called and if successful
willreturn an I/O Input buffer</li>
<li>the parser will the start reading from this buffer and
progressivelyfetch information from the resource, calling the read()
function of thehandler until the resource is exhausted</li>
<li>if an encoding change is detected it will be installed on the
inputbuffer, providing buffering and efficient use of the
conversionroutines</li>
<li>once the parser has finished, the close() function of the handler
iscalled once and the Input buffer and associated resources
aredeallocated.</li>
</ol>
<p>The user defined callbacks are checked first to allow overriding of
thedefault libxml2 I/O routines.</p>
<h3><a name="basic">The basic buffer type</a></h3>
<p>All the buffer manipulation handling is done using
the<code>xmlBuffer</code>type define in <code><a
href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a></code>which is
aresizable memory buffer. The buffer allocation strategy can be selected to
beeither best-fit or use an exponential doubling one (CPU vs. memory
usetrade-off). The values are
<code>XML_BUFFER_ALLOC_EXACT</code>and<code>XML_BUFFER_ALLOC_DOUBLEIT</code>,
and can be set individually or on asystem wide basis using
<code>xmlBufferSetAllocationScheme()</code>. A numberof functions allows to
manipulate buffers with names starting with
the<code>xmlBuffer...</code>prefix.</p>
<h3><a name="Input">Input I/O handlers</a></h3>
<p>An Input I/O handler is a simple
structure<code>xmlParserInputBuffer</code>containing a context associated to
theresource (file descriptor, or pointer to a protocol handler), the read()
andclose() callbacks to use and an xmlBuffer. And extra xmlBuffer and a
charsetencoding handler are also present to support charset conversion
whenneeded.</p>
<h3><a name="Output">Output I/O handlers</a></h3>
<p>An Output handler <code>xmlOutputBuffer</code>is completely similar to
anInput one except the callbacks are write() and close().</p>
<h3><a name="entities">The entities loader</a></h3>
<p>The entity loader resolves requests for new entities and create inputs
forthe parser. Creating an input from a filename or an URI string is
donethrough the xmlNewInputFromFile() routine. The default entity loader do
nothandle the PUBLIC identifier associated with an entity (if any). So it
justcalls xmlNewInputFromFile() with the SYSTEM identifier (which is
mandatory inXML).</p>
<p>If you want to hook up a catalog mechanism then you simply need tooverride
the default entity loader, here is an example:</p>
<pre>#include &lt;libxml/xmlIO.h&gt;
xmlExternalEntityLoader defaultLoader = NULL;
xmlParserInputPtr
xmlMyExternalEntityLoader(const char *URL, const char *ID,
xmlParserCtxtPtr ctxt) {
xmlParserInputPtr ret;
const char *fileID = NULL;
/* lookup for the fileID depending on ID */
ret = xmlNewInputFromFile(ctxt, fileID);
if (ret != NULL)
return(ret);
if (defaultLoader != NULL)
ret = defaultLoader(URL, ID, ctxt);
return(ret);
}
int main(..) {
...
/*
* Install our own entity loader
*/
defaultLoader = xmlGetExternalEntityLoader();
xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
...
}</pre>
<h3><a name="Example2">Example of customized I/O</a></h3>
<p>This example come from <a
href="http://xmlsoft.org/messages/0708.html">areal use case</a>,
xmlDocDump() closes the FILE * passed by the applicationand this was a
problem. The <a href="http://xmlsoft.org/messages/0711.html">solution</a>was
to redefine anew output handler with the closing call deactivated:</p>
<ol>
<li>First define a new I/O output allocator where the output don't closethe
file:
<pre>xmlOutputBufferPtr
xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) {
    xmlOutputBufferPtr ret;
    
    if (xmlOutputCallbackInitialized == 0)
        xmlRegisterDefaultOutputCallbacks();
    if (file == NULL) return(NULL);
    ret = xmlAllocOutputBuffer(encoder);
    if (ret != NULL) {
        ret-&gt;context = file;
        ret-&gt;writecallback = xmlFileWrite;
        ret-&gt;closecallback = NULL; /* No close callback */
    }
    return(ret);
} </pre>
</li>
<li>And then use it to save the document:
<pre>FILE *f;
xmlOutputBufferPtr output;
xmlDocPtr doc;
int res;
f = ...
doc = ....
output = xmlOutputBufferCreateOwn(f, NULL);
res = xmlSaveFileTo(output, doc, NULL);
</pre>
</li>
</ol>
<h2><a name="Catalog">Catalog support</a></h2>
<p>Table of Content:</p>
<ol>
<li><a href="General2">General overview</a></li>
<li><a href="#definition">The definition</a></li>
<li><a href="#Simple">Using catalogs</a></li>
<li><a href="#Some">Some examples</a></li>
<li><a href="#reference">How to tune catalog usage</a></li>
<li><a href="#validate">How to debug catalog processing</a></li>
<li><a href="#Declaring">How to create and maintain catalogs</a></li>
<li><a href="#implemento">The implementor corner quick review of
theAPI</a></li>
<li><a href="#Other">Other resources</a></li>
</ol>
<h3><a name="General2">General overview</a></h3>
<p>What is a catalog? Basically it's a lookup mechanism used when an entity(a
file or a remote resource) references another entity. The catalog lookupis
inserted between the moment the reference is recognized by the software(XML
parser, stylesheet processing, or even images referenced for inclusionin a
rendering) and the time where loading that resource is actuallystarted.</p>
<p>It is basically used for 3 things:</p>
<ul>
<li>mapping from "logical" names, the public identifiers and a moreconcrete
name usable for download (and URI). For example it can associatethe
logical name
<p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
<p>of the DocBook 4.1.2 XML DTD with the actual URL where it can
bedownloaded</p>
<p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
</li>
<li>remapping from a given URL to another one, like an HTTP
indirectionsaying that
<p>"http://www.oasis-open.org/committes/tr.xsl"</p>
<p>should really be looked at</p>
<p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
</li>
<li>providing a local cache mechanism allowing to load the
entitiesassociated to public identifiers or remote resources, this is a
reallyimportant feature for any significant deployment of XML or SGML
since itallows to avoid the aleas and delays associated to fetching
remoteresources.</li>
</ul>
<h3><a name="definition">The definitions</a></h3>
<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p>
<ul>
<li>the older SGML catalogs, the official spec is SGML Open
TechnicalResolution TR9401:1997, but is better understood by reading <a
href="http://www.jclark.com/sp/catalog.htm">the SP Catalog
page</a>fromJames Clark. This is relatively old and not the preferred
mode ofoperation of libxml.</li>
<li><a
href="http://www.oasis-open.org/committees/entity/spec.html">XMLCatalogs</a>is
far more flexible, more recent, uses an XML syntax andshould scale quite
better. This is the default option of libxml.</li>
</ul>
<p></p>
<h3><a name="Simple">Using catalog</a></h3>
<p>In a normal environment libxml2 will by default check the presence of
acatalog in /etc/xml/catalog, and assuming it has been correctly
populated,the processing is completely transparent to the document user. To
take aconcrete example, suppose you are authoring a DocBook document, this
onestarts with the following DOCTYPE definition:</p>
<pre>&lt;?xml version='1.0'?&gt;
&lt;!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"&gt;</pre>
<p>When validating the document with libxml, the catalog will beautomatically
consulted to lookup the public identifier "-//Norman Walsh//DTDDocBk XML
V3.1.4//EN" and the system
identifier"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these
entities havebeen installed on your system and the catalogs actually point to
them, libxmlwill fetch them from the local disk.</p>
<p style="font-size: 10pt"><strong>Note</strong>: Really don't use
thisDOCTYPE example it's a really old version, but is fine as an example.</p>
<p>Libxml2 will check the catalog each time that it is requested to load
anentity, this includes DTD, external parsed entities, stylesheets, etc ...
Ifyour system is correctly configured all the authoring phase and
processingshould use only local files, even if your document stays portable
because ituses the canonical public and system ID, referencing the remote
document.</p>
<h3><a name="Some">Some examples:</a></h3>
<p>Here is a couple of fragments from XML Catalogs used in libxml2
earlyregression tests in <code>test/catalogs</code>:</p>
<pre>&lt;?xml version="1.0"?&gt;
&lt;!DOCTYPE catalog PUBLIC
"-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
"http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
&lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
...</pre>
<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs
arewritten in XML, there is a specific namespace for catalog
elements"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in
thiscatalog is a <code>public</code>mapping it allows to associate a
PublicIdentifier with an URI.</p>
<pre>...
&lt;rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
rewritePrefix="file:///usr/share/xml/docbook/"/&gt;
...</pre>
<p>A <code>rewriteSystem</code>is a very powerful instruction, it says
thatany URI starting with a given prefix should be looked at another
URIconstructed by replacing the prefix with an new one. In effect this acts
likea cache system for a full area of the Web. In practice it is extremely
usefulwith a file prefix if you have installed a copy of those resources on
yourlocal system.</p>
<pre>...
&lt;delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
catalog="file:///usr/share/xml/docbook.xml"/&gt;
&lt;delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
catalog="file:///usr/share/xml/docbook.xml"/&gt;
&lt;delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
catalog="file:///usr/share/xml/docbook.xml"/&gt;
&lt;delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
catalog="file:///usr/share/xml/docbook.xml"/&gt;
&lt;delegateURI uriStartString="http://www.oasis-open.org/docbook/"
catalog="file:///usr/share/xml/docbook.xml"/&gt;
...</pre>
<p>Delegation is the core features which allows to build a tree of
catalogs,easier to maintain than a single catalog, based on Public
Identifier, SystemIdentifier or URI prefixes it instructs the catalog
software to look upentries in another resource. This feature allow to build
hierarchies ofcatalogs, the set of entries presented should be sufficient to
redirect theresolution of all DocBook references to the specific catalog
in<code>/usr/share/xml/docbook.xml</code>this one in turn could delegate
allreferences for DocBook 4.2.1 to a specific catalog installed at the same
timeas the DocBook resources on the local machine.</p>
<h3><a name="reference">How to tune catalog usage:</a></h3>
<p>The user can change the default catalog behaviour by redirecting queriesto
its own set of catalogs, this can be done by setting
the<code>XML_CATALOG_FILES</code>environment variable to a list of catalogs,
anempty one should deactivate loading the default
<code>/etc/xml/catalog</code>default catalog</p>
<h3><a name="validate">How to debug catalog processing:</a></h3>
<p>Setting up the <code>XML_DEBUG_CATALOG</code>environment variable willmake
libxml2 output debugging informations for each catalog operations,
forexample:</p>
<pre>orchis:~/XML -&gt; xmllint --memory --noout test/ent2
warning: failed to load external entity "title.xml"
orchis:~/XML -&gt; export XML_DEBUG_CATALOG=
orchis:~/XML -&gt; xmllint --memory --noout test/ent2
Failed to parse catalog /etc/xml/catalog
Failed to parse catalog /etc/xml/catalog
warning: failed to load external entity "title.xml"
Catalogs cleanup
orchis:~/XML -&gt; </pre>
<p>The test/ent2 references an entity, running the parser from memory
makesthe base URI unavailable and the the "title.xml" entity cannot be
loaded.Setting up the debug environment variable allows to detect that an
attempt ismade to load the <code>/etc/xml/catalog</code>but since it's not
present theresolution fails.</p>
<p>But the most advanced way to debug XML catalog processing is to use
the<strong>xmlcatalog</strong>command shipped with libxml2, it allows to
loadcatalogs and make resolution queries to see what is going on. This is
alsoused for the regression tests:</p>
<pre>orchis:~/XML -&gt; ./xmlcatalog test/catalogs/docbook.xml \
"-//OASIS//DTD DocBook XML V4.1.2//EN"
http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
orchis:~/XML -&gt; </pre>
<p>For debugging what is going on, adding one -v flags increase the
verbositylevel to indicate the processing done (adding a second flag also
indicatewhat elements are recognized at parsing):</p>
<pre>orchis:~/XML -&gt; ./xmlcatalog -v test/catalogs/docbook.xml \
"-//OASIS//DTD DocBook XML V4.1.2//EN"
Parsing catalog test/catalogs/docbook.xml's content
Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
Catalogs cleanup
orchis:~/XML -&gt; </pre>
<p>A shell interface is also available to debug and process multiple
queries(and for regression tests):</p>
<pre>orchis:~/XML -&gt; ./xmlcatalog -shell test/catalogs/docbook.xml \
"-//OASIS//DTD DocBook XML V4.1.2//EN"
&gt; help
Commands available:
public PublicID: make a PUBLIC identifier lookup
system SystemID: make a SYSTEM identifier lookup
resolve PublicID SystemID: do a full resolver lookup
add 'type' 'orig' 'replace' : add an entry
del 'values' : remove values
dump: print the current catalog state
debug: increase the verbosity level
quiet: decrease the verbosity level
exit: quit the shell
&gt; public "-//OASIS//DTD DocBook XML V4.1.2//EN"
http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
&gt; quit
orchis:~/XML -&gt; </pre>
<p>This should be sufficient for most debugging purpose, this was
actuallyused heavily to debug the XML Catalog implementation itself.</p>
<h3><a name="Declaring">How to create and maintain</a>catalogs:</h3>
<p>Basically XML Catalogs are XML files, you can either use XML tools
tomanage them or use <strong>xmlcatalog</strong>for this. The basic step
isto create a catalog the -create option provide this facility:</p>
<pre>orchis:~/XML -&gt; ./xmlcatalog --create tst.xml
&lt;?xml version="1.0"?&gt;
&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
"http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
orchis:~/XML -&gt; </pre>
<p>By default xmlcatalog does not overwrite the original catalog and save
theresult on the standard output, this can be overridden using the
-nooutoption. The <code>-add</code>command allows to add entries in
thecatalog:</p>
<pre>orchis:~/XML -&gt; ./xmlcatalog --noout --create --add "public" \
"-//OASIS//DTD DocBook XML V4.1.2//EN" \
http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
orchis:~/XML -&gt; cat tst.xml
&lt;?xml version="1.0"?&gt;
&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
"http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
&lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
&lt;/catalog&gt;
orchis:~/XML -&gt; </pre>
<p>The <code>-add</code>option will always take 3 parameters even if some
ofthe XML Catalog constructs (like nextCatalog) will have only a
singleargument, just pass a third empty string, it will be ignored.</p>
<p>Similarly the <code>-del</code>option remove matching entries from
thecatalog:</p>
<pre>orchis:~/XML -&gt; ./xmlcatalog --del \
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
&lt;?xml version="1.0"?&gt;
&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
"http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
orchis:~/XML -&gt; </pre>
<p>The catalog is now empty. Note that the matching of
<code>-del</code>isexact and would have worked in a similar fashion with the
Public IDstring.</p>
<p>This is rudimentary but should be sufficient to manage a not too
complexcatalog tree of resources.</p>
<h3><a name="implemento">The implementor corner quick review of
theAPI:</a></h3>
<p>First, and like for every other module of libxml, there is anautomatically
generated <a href="html/libxml-catalog.html">API page forcatalog
support</a>.</p>
<p>The header for the catalog interfaces should be included as:</p>
<pre>#include &lt;libxml/catalog.h&gt;</pre>
<p>The API is voluntarily kept very simple. First it is not obvious
thatapplications really need access to it since it is the default behaviour
oflibxml2 (Note: it is possible to completely override libxml2 default
catalogby using <a
href="html/libxml-parser.html">xmlSetExternalEntityLoader</a>toplug an
application specific resolver).</p>
<p>Basically libxml2 support 2 catalog lists:</p>
<ul>
<li>the default one, global shared by all the application</li>
<li>a per-document catalog, this one is built if the document uses
the<code>oasis-xml-catalog</code>PIs to specify its own catalog list, it
isassociated to the parser context and destroyed when the parsing
contextis destroyed.</li>
</ul>
<p>the document one will be used first if it exists.</p>
<h4>Initialization routines:</h4>
<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should
beused at startup to initialize the catalog, if the catalog should
beinitialized with specific values xmlLoadCatalog() or
xmlLoadCatalogs()should be called before xmlInitializeCatalog() which would
otherwise do adefault initialization first.</p>
<p>The xmlCatalogAddLocal() call is used by the parser to grow the
documentown catalog list if needed.</p>
<h4>Preferences setup:</h4>
<p>The XML Catalog spec requires the possibility to select defaultpreferences
between public and system delegation,xmlCatalogSetDefaultPrefer() allows
this, xmlCatalogSetDefaults() andxmlCatalogGetDefaults() allow to control if
XML Catalogs resolution shouldbe forbidden, allowed for global catalog, for
document catalog or both, thedefault is to allow both.</p>
<p>And of course xmlCatalogSetDebug() allows to generate debug
messages(through the xmlGenericError() mechanism).</p>
<h4>Querying routines:</h4>
<p>xmlCatalogResolve(), xmlCatalogResolveSystem(),
xmlCatalogResolvePublic()and xmlCatalogResolveURI() are relatively explicit
if you read the XMLCatalog specification they correspond to section 7
algorithms, they shouldalso work if you have loaded an SGML catalog with a
simplified semantic.</p>
<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same
butoperate on the document catalog list</p>
<h4>Cleanup and Miscellaneous:</h4>
<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal()
isthe per-document equivalent.</p>
<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify
thefirst catalog in the global list, and xmlCatalogDump() allows to dump
acatalog state, those routines are primarily designed for xmlcatalog, I'm
notsure that exposing more complex interfaces (like navigation ones) would
bereally useful.</p>
<p>The xmlParseCatalogFile() is a function used to load XML Catalog
files,it's similar as xmlParseFile() except it bypass all catalog lookups,
it'sprovided because this functionality may be useful for client tools.</p>
<h4>threaded environments:</h4>
<p>Since the catalog tree is built progressively, some care has been taken
totry to avoid troubles in multithreaded environments. The code is now
threadsafe assuming that the libxml2 library has been compiled with
threadssupport.</p>
<p></p>
<h3><a name="Other">Other resources</a></h3>
<p>The XML Catalog specification is relatively recent so there isn't
muchliterature to point at:</p>
<ul>
<li>You can find a good rant from Norm Walsh about <a
href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">theneed
for catalogs</a>, it provides a lot of context informations even ifI
don't agree with everything presented. Norm also wrote a more
recentarticle <a
href="http://wwws.sun.com/software/xml/developers/resolver/article/">XMLentities
and URI resolvers</a>describing them.</li>
<li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old
XMLcatalog proposal</a>from John Cowan</li>
<li>The <a href="http://www.rddl.org/">Resource Directory
DescriptionLanguage</a>(RDDL) another catalog system but more oriented
towardproviding metadata for XML namespaces.</li>
<li>the page from the OASIS Technical <a
href="http://www.oasis-open.org/committees/entity/">Committee on
EntityResolution</a>who maintains XML Catalog, you will find pointers to
thespecification update, some background and pointers to others
toolsproviding XML Catalog support</li>
<li>There is a <a href="buildDocBookCatalog">shell script</a>to generateXML
Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/directory,
it will set-up /etc/xml/catalog and /etc/xml/docbook based onthe
resources found on the system. Otherwise it will just create~/xmlcatalog
and ~/dbkxmlcatalog and doing:
<p><code>export XML_CATALOG_FILES=$HOME/xmlcatalog</code></p>
<p>should allow to process DocBook documentations without
requiringnetwork accesses for the DTD or stylesheets</p>
</li>
<li>I have uploaded <a
href="ftp://xmlsoft.org/libxml2/test/dbk412catalog.tar.gz">asmall
tarball</a>containing XML Catalogs for DocBook 4.1.2 which seemsto work
fine for me too</li>
<li>The <a
href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalogmanual
page</a></li>
</ul>
<p>If you have suggestions for corrections or additions, simply contactme:</p>
<h2><a name="library">The parser interfaces</a></h2>
<p>This section is directly intended to help programmers getting
bootstrappedusing the XML tollkit from the C language. It is not intended to
beextensive. I hope the automatically generated documents will provide
thecompleteness required, but as a separate set of documents. The interfaces
ofthe XML parser are by principle low level, Those interested in a higher
levelAPI should <a href="#DOM">look at DOM</a>.</p>
<p>The <a href="html/libxml-parser.html">parser interfaces for
XML</a>areseparated from the <a href="html/libxml-htmlparser.html">HTML
parserinterfaces</a>. Let's have a look at how the XML parser can be
called:</p>
<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
<p>Usually, the first thing to do is to read an XML input. The parser
acceptsdocuments either from in-memory strings or from files. The functions
aredefined in "parser.h":</p>
<dl>
<dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
<dd><p>Parse a null-terminated string containing the document.</p>
</dd>
</dl>
<dl>
<dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
<dd><p>Parse an XML document contained in a (possibly compressed)file.</p>
</dd>
</dl>
<p>The parser returns a pointer to the document structure (or NULL in case
offailure).</p>
<h3 id="Invoking1">Invoking the parser: the push method</h3>
<p>In order for the application to keep the control when the document isbeing
fetched (which is common for GUI based programs) libxml2 provides apush
interface, too, as of version 1.8.3. Here are the interfacefunctions:</p>
<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
void *user_data,
const char *chunk,
int size,
const char *filename);
int xmlParseChunk (xmlParserCtxtPtr ctxt,
const char *chunk,
int size,
int terminate);</pre>
<p>and here is a simple example showing how to use the interface:</p>
<pre> FILE *f;
f = fopen(filename, "r");
if (f != NULL) {
int res, size = 1024;
char chars[1024];
xmlParserCtxtPtr ctxt;
res = fread(chars, 1, 4, f);
if (res &gt; 0) {
ctxt = xmlCreatePushParserCtxt(NULL, NULL,
chars, res, filename);
while ((res = fread(chars, 1, size, f)) &gt; 0) {
xmlParseChunk(ctxt, chars, res, 0);
}
xmlParseChunk(ctxt, chars, 0, 1);
doc = ctxt-&gt;myDoc;
xmlFreeParserCtxt(ctxt);
}
}</pre>
<p>The HTML parser embedded into libxml2 also has a push interface;
thefunctions are just prefixed by "html" rather than "xml".</p>
<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
<p>The tree-building interface makes the parser memory-hungry, first
loadingthe document in memory and then building the tree itself. Reading a
documentwithout building the tree is possible using the SAX interfaces (see
SAX.h and<a
href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">JamesHenstridge's
documentation</a>). Note also that the push interface can belimited to SAX:
just use the two first arguments of<code>xmlCreatePushParserCtxt()</code>.</p>
<h3><a name="Building">Building a tree from scratch</a></h3>
<p>The other way to get an XML tree in memory is by building it.
Basicallythere is a set of functions dedicated to building new elements.
(These arealso described in &lt;libxml/tree.h&gt;.) For example, here is a
piece ofcode that produces the XML document used in the previous examples:</p>
<pre> #include &lt;libxml/tree.h&gt;
xmlDocPtr doc;
xmlNodePtr tree, subtree;
doc = xmlNewDoc("1.0");
doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
subtree = xmlNewChild(tree, NULL, "image", NULL);
xmlSetProp(subtree, "href", "linus.gif");</pre>
<p>Not really rocket science ...</p>
<h3><a name="Traversing">Traversing the tree</a></h3>
<p>Basically by <a href="html/libxml-tree.html">including
"tree.h"</a>yourcode has access to the internal structure of all the elements
of the tree.The names should be somewhat simple like
<strong>parent</strong>,<strong>children</strong>, <strong>next</strong>,
<strong>prev</strong>,<strong>properties</strong>, etc... For example, still
with the previousexample:</p>
<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
<p>points to the title element,</p>
<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
<p>points to the text node containing the chapter title "The
Linuxadventure".</p>
<p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em>to
bepresent before the document root, so <code>doc-&gt;children</code>may
pointto an element which is not the document Root Element; a
function<code>xmlDocGetRootElement()</code>was added for this purpose.</p>
<h3><a name="Modifying">Modifying the tree</a></h3>
<p>Functions are provided for reading and writing the document content.
Hereis an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
<dl>
<dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name,
constxmlChar *value);</code></dt>
<dd><p>This sets (or changes) an attribute carried by an ELEMENT node.The
value can be NULL.</p>
</dd>
</dl>
<dl>
<dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const
xmlChar*name);</code></dt>
<dd><p>This function returns a pointer to new copy of the
propertycontent. Note that the user must deallocate the result.</p>
</dd>
</dl>
<p>Two functions are provided for reading and writing the text associatedwith
elements:</p>
<dl>
<dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const
xmlChar*value);</code></dt>
<dd><p>This function takes an "external" string and converts it to
onetext node or possibly to a list of entity and text nodes.
Allnon-predefined entity references like &amp;Gnome; will be
storedinternally as entity nodes, hence the result of the function may
not bea single node.</p>
</dd>
</dl>
<dl>
<dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list,
intinLine);</code></dt>
<dd><p>This function is the inverse
of<code>xmlStringGetNodeList()</code>. It generates a new
stringcontaining the content of the text and entity nodes. Note the
extraargument inLine. If this argument is set to 1, the function will
expandentity references. For example, instead of returning the
&amp;Gnome;XML encoding in the string, it will substitute it with its
value (say,"GNU Network Object Model Environment").</p>
</dd>
</dl>
<h3><a name="Saving">Saving a tree</a></h3>
<p>Basically 3 options are possible:</p>
<dl>
<dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem,
int*size);</code></dt>
<dd><p>Returns a buffer into which the document has been saved.</p>
</dd>
</dl>
<dl>
<dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
<dd><p>Dumps a document to an open file descriptor.</p>
</dd>
</dl>
<dl>
<dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
<dd><p>Saves the document to a file. In this case, the
compressioninterface is triggered if it has been turned on.</p>
</dd>
</dl>
<h3><a name="Compressio">Compression</a></h3>
<p>The library transparently handles compression when doing
file-basedaccesses. The level of compression on saves can be turned on either
globallyor individually for one file:</p>
<dl>
<dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
<dd><p>Gets the document compression ratio (0-9).</p>
</dd>
</dl>
<dl>
<dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
<dd><p>Sets the document compression ratio.</p>
</dd>
</dl>
<dl>
<dt><code>int xmlGetCompressMode(void);</code></dt>
<dd><p>Gets the default compression ratio.</p>
</dd>
</dl>
<dl>
<dt><code>void xmlSetCompressMode(int mode);</code></dt>
<dd><p>Sets the default compression ratio.</p>
</dd>
</dl>
<h2><a name="Entities">Entities or no entities</a></h2>
<p>Entities in principle are similar to simple C macros. An entity defines
anabbreviation for a given string that you can reuse many times throughout
thecontent of your document. Entities are especially useful when a given
stringmay occur frequently within a document, or to confine the change needed
to adocument to a restricted area in the internal subset of the document (at
thebeginning). Example:</p>
<pre>1 &lt;?xml version="1.0"?&gt;
2 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
3 &lt;!ENTITY xml "Extensible Markup Language"&gt;
4 ]&gt;
5 &lt;EXAMPLE&gt;
6 &amp;xml;
7 &lt;/EXAMPLE&gt;</pre>
<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by
prefixingits name with '&amp;' and following it by ';' without any spaces
added. Thereare 5 predefined entities in libxml2 allowing you to escape
characters withpredefined meaning in some parts of the xml document
content:<strong>&amp;lt;</strong>for the character '&lt;',
<strong>&amp;gt;</strong>for the character '&gt;',
<strong>&amp;apos;</strong>for the character
''',<strong>&amp;quot;</strong>for the character '"',
and<strong>&amp;amp;</strong>for the character '&amp;'.</p>
<p>One of the problems related to entities is that you may want the parser
tosubstitute an entity's content so that you can see the replacement text
inyour application. Or you may prefer to keep entity references as such in
thecontent to be able to save the document back without losing this
usuallyprecious information (if the user went through the pain of
explicitlydefining entities, he may have a a rather negative attitude if you
blindlysubstitute them as saving time). The <a
href="html/libxml-parser.html#xmlSubstituteEntitiesDefault">xmlSubstituteEntitiesDefault()</a>function
allows you to check and change the behaviour, which is to notsubstitute
entities by default.</p>
<p>Here is the DOM tree built by libxml2 for the previous document in
thedefault case:</p>
<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
DOCUMENT
version=1.0
ELEMENT EXAMPLE
TEXT
content=
ENTITY_REF
INTERNAL_GENERAL_ENTITY xml
content=Extensible Markup Language
TEXT
content=</pre>
<p>And here is the result when substituting entities:</p>
<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
DOCUMENT
version=1.0
ELEMENT EXAMPLE
TEXT
content= Extensible Markup Language</pre>
<p>So, entities or no entities? Basically, it depends on your use case.
Isuggest that you keep the non-substituting default behaviour and avoid
usingentities in your XML document or data if you are not willing to handle
theentity references elements in the DOM tree.</p>
<p>Note that at save time libxml2 enforces the conversion of the
predefinedentities where necessary to prevent well-formedness problems, and
will alsotransparently replace those with chars (i.e. it will not generate
entityreference elements in the DOM tree or call the reference() SAX callback
whenfinding them in the input).</p>
<p><span style="background-color: #FF0000">WARNING</span>: handling
entitieson top of the libxml2 SAX interface is difficult!!! If you plan to
usenon-predefined entities in your documents, then the learning curve to
handlethen using the SAX API may be long. If you plan to use complex
documents, Istrongly suggest you consider using the DOM interface instead and
let libxmldeal with the complexity rather than trying to do it yourself.</p>
<h2><a name="Namespaces">Namespaces</a></h2>
<p>The libxml2 library implements <a
href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a>support
byrecognizing namespace constructs in the input, and does namespace
lookupautomatically when building the DOM tree. A namespace declaration
isassociated with an in-memory structure and all elements or attributes
withinthat namespace point to it. Hence testing the namespace is a simple and
fastequality operation at the user level.</p>
<p>I suggest that people using libxml2 use a namespace, and declare it in
theroot element of their document as the default namespace. Then they don't
needto use the prefix in the content but we will have a basis for future
semanticrefinement and merging of data from different sources. This doesn't
increasethe size of the XML output significantly, but significantly increases
itsvalue in the long-term. Example:</p>
<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
&lt;elem1&gt;...&lt;/elem1&gt;
&lt;elem2&gt;...&lt;/elem2&gt;
&lt;/mydoc&gt;</pre>
<p>The namespace value has to be an absolute URL, but the URL doesn't have
topoint to any existing resource on the Web. It will bind all the element
andattributes with that URL. I suggest to use an URL within a domain
youcontrol, and that the URL should contain some kind of version information
ifpossible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code>is
agood namespace scheme.</p>
<p>Then when you load a file, make sure that a namespace carrying
theversion-independent prefix is installed on the root element of your
document,and if the version information don't match something you know, warn
the userand be liberal in what you accept as the input. Also do *not* try to
basenamespace checking on the prefix value. &lt;foo:text&gt; may be exactly
thesame as &lt;bar:text&gt; in another document. What really matters is the
URIassociated with the element or the attribute, not the prefix string (which
isjust a shortcut for the full URI). In libxml, element and attributes have
an<code>ns</code>field pointing to an xmlNs structure detailing the
namespaceprefix and its URI.</p>
<p>@@Interfaces@@</p>
<pre>xmlNodePtr node;
if(!strncmp(node-&gt;name,"mytag",5)
&amp;&amp; node-&gt;ns
&amp;&amp; !strcmp(node-&gt;ns-&gt;href,"http://www.mysite.com/myns/1.0")) {
...
}</pre>
<p>Usually people object to using namespaces together with validity
checking.I will try to make sure that using namespaces won't break validity
checking,so even if you plan to use or currently are using validation I
stronglysuggest adding namespaces to your document. A default namespace
scheme<code>xmlns="http://...."</code>should not break validity even on
lessflexible parsers. Using namespaces to mix and differentiate content
comingfrom multiple DTDs will certainly break current validation schemes. To
checksuch documents one needs to use schema-validation, which is supported
inlibxml2 as well. See <a href="http://www.relaxng.org/">relagx-ng</a>and <a
href="http://www.w3c.org/XML/Schema">w3c-schema</a>.</p>
<h2><a name="Upgrading">Upgrading 1.x code</a></h2>
<p>Incompatible changes:</p>
<p>Version 2 of libxml2 is the first version introducing serious
backwardincompatible changes. The main goals were:</p>
<ul>
<li>a general cleanup. A number of mistakes inherited from the very
earlyversions couldn't be changed due to compatibility constraints.
Examplethe "childs" element in the nodes.</li>
<li>Uniformization of the various nodes, at least for their header and
linkparts (doc, parent, children, prev, next), the goal is a
simplerprogramming model and simplifying the task of the DOM
implementors.</li>
<li>better conformances to the XML specification, for example version
1.xhad an heuristic to try to detect ignorable white spaces. As a result
theSAX event generated were ignorableWhitespace() while the spec
requirescharacter() in that case. This also mean that a number of DOM
nodecontaining blank text may populate the DOM tree which were not
presentbefore.</li>
</ul>
<h3>How to fix libxml-1.x code:</h3>
<p>So client code of libxml designed to run with version 1.x may have to
bechanged to compile against version 2.x of libxml. Here is a list of
changesthat I have collected, they may not be sufficient, so in case you find
otherchange which are required, <a href="mailto:Daniel.Veillard@w3.org">drop
me amail</a>:</p>
<ol>
<li>The package name have changed from libxml to libxml2, the library
nameis now -lxml2 . There is a new xml2-config script which should be
used toselect the right parameters libxml2</li>
<li>Node <strong>childs</strong>field has been
renamed<strong>children</strong>so s/childs/children/g should be
applied(probability of having "childs" anywhere else is close to 0+</li>
<li>The document don't have anymore a <strong>root</strong>element it
hasbeen replaced by <strong>children</strong>and usually you will get
alist of element here. For example a Dtd element for the internal
subsetand it's declaration may be found in that list, as well as
processinginstructions or comments found before or after the document
root element.Use <strong>xmlDocGetRootElement(doc)</strong>to get the
root element ofa document. Alternatively if you are sure to not reference
DTDs nor havePIs or comments before or after the root
elements/-&gt;root/-&gt;children/g will probably do it.</li>
<li>The white space issue, this one is more complex, unless special case
ofvalidating parsing, the line breaks and spaces usually used for
indentingand formatting the document content becomes significant. So they
arereported by SAX and if your using the DOM tree, corresponding nodes
aregenerated. Too approach can be taken:
<ol>
<li>lazy one, use the compatibility
call<strong>xmlKeepBlanksDefault(0)</strong>but be aware that you
arerelying on a special (and possibly broken) set of heuristics
oflibxml to detect ignorable blanks. Don't complain if it breaks
ormake your application not 100% clean w.r.t. to it's input.</li>
<li>the Right Way: change you code to accept possibly
insignificantblanks characters, or have your tree populated with
weird blank textnodes. You can spot them using the commodity
function<strong>xmlIsBlankNode(node)</strong>returning 1 for such
blanknodes.</li>
</ol>
<p>Note also that with the new default the output functions don't add
anyextra indentation when saving a tree in order to be able to round
trip(read and save) without inflating the document with extra
formattingchars.</p>
</li>
<li>The include path has changed to $prefix/libxml/ and the
includesthemselves uses this new prefix in includes instructions... If
you areusing (as expected) the
<pre>xml2-config --cflags</pre>
<p>output to generate you compile commands this will probably work out
ofthe box</p>
</li>
<li>xmlDetectCharEncoding takes an extra argument indicating the length
inbyte of the head of the document available for character detection.</li>
</ol>
<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3>
<p>Two new version of libxml (1.8.11) and libxml2 (2.3.4) have been
releasedto allow smooth upgrade of existing libxml v1code while
retainingcompatibility. They offers the following:</p>
<ol>
<li>similar include naming, one should
use<strong>#include&lt;libxml/...&gt;</strong>in both cases.</li>
<li>similar identifiers defined via macros for the child and root
fields:respectively
<strong>xmlChildrenNode</strong>and<strong>xmlRootNode</strong></li>
<li>a new macro <strong>LIBXML_TEST_VERSION</strong>which should beinserted
once in the client code</li>
</ol>
<p>So the roadmap to upgrade your existing libxml applications is
thefollowing:</p>
<ol>
<li>install the libxml-1.8.8 (and libxml-devel-1.8.8) packages</li>
<li>find all occurrences where the xmlDoc <strong>root</strong>field isused
and change it to <strong>xmlRootNode</strong></li>
<li>similarly find all occurrences where the
xmlNode<strong>childs</strong>field is used and change it
to<strong>xmlChildrenNode</strong></li>
<li>add a <strong>LIBXML_TEST_VERSION</strong>macro somewhere in
your<strong>main()</strong>or in the library init entry point</li>
<li>Recompile, check compatibility, it should still work</li>
<li>Change your configure script to look first for xml2-config and fallback
using xml-config . Use the --cflags and --libs output of the commandas
the Include and Linking parameters needed to use libxml.</li>
<li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y
andlibxml-devel-1.8.y can be kept simultaneously)</li>
<li>remove your config.cache, relaunch your configuration mechanism,
andrecompile, if steps 2 and 3 were done right it should compile
as-is</li>
<li>Test that your application is still running correctly, if not this
maybe due to extra empty nodes due to formating spaces being kept in
libxml2contrary to libxml1, in that case insert xmlKeepBlanksDefault(1)
in yourcode before calling the parser (next
to<strong>LIBXML_TEST_VERSION</strong>is a fine place).</li>
</ol>
<p>Following those steps should work. It worked for some of my own code.</p>
<p>Let me put some emphasis on the fact that there is far more changes
fromlibxml 1.x to 2.x than the ones you may have to patch for. The overall
codehas been considerably cleaned up and the conformance to the XML
specificationhas been drastically improved too. Don't take those changes as
an excuse tonot upgrade, it may cost a lot on the long term ...</p>
<h2><a name="Thread">Thread safety</a></h2>
<p>Starting with 2.4.7, libxml2 makes provisions to ensure that
concurrentthreads can safely work in parallel parsing different documents.
There ishowever a couple of things to do to ensure it:</p>
<ul>
<li>configure the library accordingly using the --with-threads options</li>
<li>call xmlInitParser() in the "main" thread before using any of
thelibxml2 API (except possibly selecting a different memory
allocator)</li>
</ul>
<p>Note that the thread safety cannot be ensured for multiple threads
sharingthe same document, the locking must be done at the application level,
libxmlexports a basic mutex and reentrant mutexes API in
&lt;libxml/threads.h&gt;.The parts of the library checked for thread safety
are:</p>
<ul>
<li>concurrent loading</li>
<li>file access resolution</li>
<li>catalog access</li>
<li>catalog building</li>
<li>entities lookup/accesses</li>
<li>validation</li>
<li>global variables per-thread override</li>
<li>memory handling</li>
</ul>
<p>XPath is supposed to be thread safe now, but this wasn't
testedseriously.</p>
<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
<p><a href="http://www.w3.org/DOM/">DOM</a>stands for the <em>DocumentObject
Model</em>; this is an API for accessing XML or HTML structureddocuments.
Native support for DOM in Gnome is on the way (module gnome-dom),and will be
based on gnome-xml. This will be a far cleaner interface tomanipulate XML
files within Gnome since it won't expose the internalstructure.</p>
<p>The current DOM implementation on top of libxml2 is the <a
href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>,
thisis a full DOM interface, thanks to Paolo Casarini, check the <a
href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a>for
moreinformations.</p>
<h2><a name="Example"></a><a name="real">A real example</a></h2>
<p>Here is a real size example, where the actual content of the
applicationdata is not kept in the DOM tree but uses internal structures. It
is based ona proposal to keep a database of jobs related to Gnome, with an
XML basedstorage structure. Here is an <a href="gjobs.xml">XML encoded
jobsbase</a>:</p>
<pre>&lt;?xml version="1.0"?&gt;
&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
&lt;gjob:Jobs&gt;
&lt;gjob:Job&gt;
&lt;gjob:Project ID="3"/&gt;
&lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
&lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
&lt;gjob:Update&gt;
&lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
&lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
&lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
&lt;/gjob:Update&gt;
&lt;gjob:Developers&gt;
&lt;gjob:Developer&gt;
&lt;/gjob:Developer&gt;
&lt;/gjob:Developers&gt;
&lt;gjob:Contact&gt;
&lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
&lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
&lt;gjob:Company&gt;
&lt;/gjob:Company&gt;
&lt;gjob:Organisation&gt;
&lt;/gjob:Organisation&gt;
&lt;gjob:Webpage&gt;
&lt;/gjob:Webpage&gt;
&lt;gjob:Snailmail&gt;
&lt;/gjob:Snailmail&gt;
&lt;gjob:Phone&gt;
&lt;/gjob:Phone&gt;
&lt;/gjob:Contact&gt;
&lt;gjob:Requirements&gt;
The program should be released as free software, under the GPL.
&lt;/gjob:Requirements&gt;
&lt;gjob:Skills&gt;
&lt;/gjob:Skills&gt;
&lt;gjob:Details&gt;
A GNOME based system that will allow a superuser to configure
compressed and uncompressed files and/or file systems to be backed
up with a supported media in the system. This should be able to
perform via find commands generating a list of files that are passed
to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
or via operations performed on the filesystem itself. Email
notification and GUI status display very important.
&lt;/gjob:Details&gt;
&lt;/gjob:Job&gt;
&lt;/gjob:Jobs&gt;
&lt;/gjob:Helping&gt;</pre>
<p>While loading the XML file into an internal DOM tree is a matter ofcalling
only a couple of functions, browsing the tree to gather the data andgenerate
the internal structures is harder, and more error prone.</p>
<p>The suggested principle is to be tolerant with respect to the
inputstructure. For example, the ordering of the attributes is not
significant,the XML specification is clear about it. It's also usually a good
idea not todepend on the order of the children of a given node, unless it
really makesthings harder. Here is some code to parse the information for a
person:</p>
<pre>/*
* A person record
*/
typedef struct person {
char *name;
char *email;
char *company;
char *organisation;
char *smail;
char *webPage;
char *phone;
} person, *personPtr;
/*
* And the code needed to parse it
*/
personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
personPtr ret = NULL;
DEBUG("parsePerson\n");
/*
* allocate the struct
*/
ret = (personPtr) malloc(sizeof(person));
if (ret == NULL) {
fprintf(stderr,"out of memory\n");
return(NULL);
}
memset(ret, 0, sizeof(person));
/* We don't care what the top level element name is */
cur = cur-&gt;xmlChildrenNode;
while (cur != NULL) {
if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
cur = cur-&gt;next;
}
return(ret);
}</pre>
<p>Here are a couple of things to notice:</p>
<ul>
<li>Usually a recursive parsing style is the more convenient one: XML
datais by nature subject to repetitive constructs and usually exhibits
highlystructured patterns.</li>
<li>The two arguments of type <em>xmlDocPtr</em>and <em>xmlNsPtr</em>,i.e.
the pointer to the global XML document and the namespace reserved tothe
application. Document wide information are needed for example todecode
entities and it's a good coding practice to define a namespace foryour
application set of data and test that the element and attributesyou're
analyzing actually pertains to your application space. This isdone by a
simple equality test (cur-&gt;ns == ns).</li>
<li>To retrieve text and attributes value, you can use the
function<em>xmlNodeListGetString</em>to gather all the text and entity
referencenodes generated by the DOM output and produce an single text
string.</li>
</ul>
<p>Here is another piece of code used to parse another level of
thestructure:</p>
<pre>#include &lt;libxml/tree.h&gt;
/*
* a Description for a Job
*/
typedef struct job {
char *projectID;
char *application;
char *category;
personPtr contact;
int nbDevelopers;
personPtr developers[100]; /* using dynamic alloc is left as an exercise */
} job, *jobPtr;
/*
* And the code needed to parse it
*/
jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
jobPtr ret = NULL;
DEBUG("parseJob\n");
/*
* allocate the struct
*/
ret = (jobPtr) malloc(sizeof(job));
if (ret == NULL) {
fprintf(stderr,"out of memory\n");
return(NULL);
}
memset(ret, 0, sizeof(job));
/* We don't care what the top level element name is */
cur = cur-&gt;xmlChildrenNode;
while (cur != NULL) {
if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
ret-&gt;projectID = xmlGetProp(cur, "ID");
if (ret-&gt;projectID == NULL) {
fprintf(stderr, "Project has no ID\n");
}
}
if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
ret-&gt;contact = parsePerson(doc, ns, cur);
cur = cur-&gt;next;
}
return(ret);
}</pre>
<p>Once you are used to it, writing this kind of code is quite simple,
butboring. Ultimately, it could be possible to write stubbers taking either
Cdata structure definitions, a set of XML examples or an XML DTD and
producethe code needed to import and export the content between C data and
XMLstorage. This is left as an exercise to the reader :-)</p>
<p>Feel free to use <a href="example/gjobread.c">the code for the full
Cparsing example</a>as a template, it is also available with Makefile in
theGnome CVS base under gnome-xml/example</p>
<h2><a name="Contributi">Contributions</a></h2>
<ul>
<li>Bjorn Reese, William Brack and Thomas Broyer have provided a number
ofpatches, Gary Pennington worked on the validation API, threading
supportand Solaris port.</li>
<li>John Fleck helps maintaining the documentation and man pages.</li>
<li><a href="mailto:igor@zlatkovic.com">Igor Zlatkovic</a>is now
themaintainer of the Windows port, <a
href="http://www.zlatkovic.com/projects/libxml/index.html">he
providesbinaries</a></li>
<li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a>provides<a
href="http://garypennington.net/libxml2/">Solaris binaries</a></li>
<li><a
href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">MattSergeant</a>developed
<a href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper
forlibxml2/libxslt as part of the <a href="http://axkit.com/">AxKit
XMLapplication server</a></li>
<li><a href="mailto:fnatter@gmx.net">Felix Natter</a>and <a
href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a>provide <a
href="libxml-doc.el">an emacs module</a>to lookup libxml(2)
functionsdocumentation</li>
<li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a>provided <a
href="http://xmlsoft.org/messages/0488.html">man pages</a></li>
<li>there is a module for <a
href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt
supportin OpenNSD/AOLServer</a></li>
<li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a>provided
thefirst version of libxml/libxslt <a
href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
<li>Petr Kozelka provides <a
href="http://sourceforge.net/projects/libxml2-pas">Pascal units to
gluelibxml2</a>with Kylix and Delphi and other Pascal compilers</li>
<li><a href="mailto:aleksey@aleksey.com">Aleksey Sanin</a>implemented the<a
href="http://www.w3.org/Signature/">XML Canonicalization and XMLDigital
Signature</a><a href="http://www.aleksey.com/xmlsec/">implementations for
libxml2</a></li>
<li><a href="mailto:Steve.Ball@explain.com.au">Steve
Ball</a>andcontributors maintain <a
href="http://tclxml.sourceforge.net/">tclbindings for libxml2 and
libxslt</a>, as well as <a
href="http://tclxml.sf.net/tkxmllint.html">tkxmllint</a>a GUI forxmllint
and <a href="http://tclxml.sf.net/tkxsltproc.html">tkxsltproc</a>a GUI
for xsltproc.</li>
</ul>
<p></p>
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