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  • Author : Daniel Veillard
    Date : 2003-12-10 13:24:38
    Hash : c480c4ea
    Message : preparing release of libxml2-2.6.3, updated and regenerated the docs. * configure.in doc/* libxml.spec.in: preparing release of libxml2-2.6.3, updated and regenerated the docs. Daniel

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  <title>The XML C parser and toolkit of Gnome</title>
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<body bgcolor="#ffffff">
<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">web
site</a></h1>

<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1>

<p></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 available
under the <a href="http://www.opensource.org/licenses/mit-license.html">MIT
License</a>. XML itself is a metalanguage to design markup languages, i.e.
text language where semantic and structure are added to the content using
extra "markup" information enclosed between angle brackets. HTML is the most
well-known markup language. Though the library is written in C <a
href="python.html">a variety of language bindings</a> make it available in
other environments.</p>

<p>Libxml2 is known to be very portable, the library should build and work
without 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 markup
languages:</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 Committee Specification 3 December 2001 <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 May
    2001</a> except the base64Binary type</li>
</ul>

<p>In most cases libxml2 tries to implement the specifications in a
relatively strictly compliant way. As of release 2.4.16, libxml2 passes all
1800+ tests from the <a
href="http://www.oasis-open.org/committees/xml-conformance/">OASIS XML Tests
Suite</a>.</p>

<p>To some extent libxml2 provides support for the following additional
specifications 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>
    it doesn't implement the API itself, gdome2 does this 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 minimal SAX implementation compatible with early expat
  versions</li>
  <li>DocBook SGML v4: libxml2 includes a hackish parser to transition to
  XML</li>
</ul>

<p>A partial implementation of <a
href="http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/">XML Schemas Part
1: Structure</a> is being worked on but it would be far too early to make any
conformance statement about it at the moment.</p>

<p>Separate documents:</p>
<ul>
  <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a> providing an
    implementation of XSLT 1.0 and common extensions like EXSLT for
  libxml2</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>: an
    implementation of <a href="http://www.w3.org/TR/xmldsig-core/">W3C XML
    Digital Signature</a> for libxml2</li>
  <li>also check the related links section below for more related and active
    projects.</li>
</ul>

<p>Results of the <a
href="http://xmlbench.sourceforge.net/results/benchmark/index.html">xmlbench
benchmark</a> on sourceforge 19 March 2003 (smaller is better):</p>

<p align="center"><img src="benchmark.gif"
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-based
structured documents/data.</p>

<p>Here are some key points about libxml:</p>
<ul>
  <li>Libxml2 exports Push (progressive) and Pull (blocking) type parser
    interfaces for both XML and HTML.</li>
  <li>Libxml2 can do DTD validation at parse time, using a parsed document
    instance, 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, and
    sticking closely to ANSI C/POSIX for easy embedding. Works on
    Linux/Unix/Windows, ported to a number of other platforms.</li>
  <li>Basic support for HTTP and FTP client allowing applications to fetch
    remote 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">MIT
    License</a>. See the Copyright file in the distribution for the precise
    wording.</li>
</ul>

<p>Warning: unless you are forced to because your application links with a
Gnome-1.X library requiring it,  <strong><span
style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use
libxml2</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">MIT
    License</a>; see the file Copyright in the distribution for the precise
    wording</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 you
    made to libxml, but it would be graceful to send-back bug fixes and
    improvements as patches for possible incorporation in the main
    development tree.</p>
  </li>
</ol>

<h3><a name="Installati">Installation</a></h3>
<ol>
  <li><strong><span style="background-color: #FF0000">Do Not Use
    libxml1</span></strong>, use libxml2</li>
  <li><em>Where can I get libxml</em> ?
    <p>The original distribution comes from <a
    href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a
    href="ftp://ftp.gnome.org/pub/GNOME/sources/libxml2/2.5/">gnome.org</a></p>
    <p>Most Linux and BSD distributions include libxml, this is probably the
    safer 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 with
        existing 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> are
        compatible (this is not the case for development packages).</li>
      <li>If you are a developer and your system provides separate packaging
        for shared libraries and the development components, it is possible
        to 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 against
        libxml2(-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 shared
    library for libxml.so.0, you can probably safely remove it. The libxml
    packages provided on <a
    href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provide
    libxml.so.0</p>
  </li>
  <li><em>I can't install the libxml(2) RPM package due to failed
    dependencies</em>
    <p>The most generic solution is to re-fetch the latest src.rpm , and
    rebuild 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 (one
    providing the shared libs and xmllint, and the other one, the -devel
    package, providing includes, static libraries and scripts needed to build
    applications 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 to
    update 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 API
    should be sufficient (please report any violation to this rule you may
    find).</p>
    <p>However if found at configuration time libxml2 will detect and use the
    following libs:</p>
    <ul>
      <li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a> : a
        highly portable and available widely compression library.</li>
      <li>iconv: a powerful character encoding conversion library. It is
        included by default in recent glibc libraries, so it doesn't need to
        be installed specifically on Linux. It now seems a <a
        href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part
        of the official UNIX</a> specification. Here is one <a
        href="http://www.gnu.org/software/libiconv/">implementation of the
        library</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 the
    value produced by the parser, and the makefile uses diff to print the
    delta. 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 limitations
    in 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 the
    autogen.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 the
    optimizer which miscompiles the URI module. Please use another
    compiler.</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 get
    the right compilation or linking flags. There is a small shell script
    <code>xml2-config</code> which is installed as part of libxml2 usual
    install 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 the
    Makefile as:</p>
    <p><code>CFLAGS=`xml2-config --cflags`</code></p>
    <p><code>LIBS=`xml2-config --libs`</code></p>
  </li>
  <li><em>xmlDocDump() generates output on one line.</em>
    <p>Libxml2 will not <strong>invent</strong> spaces in the content of a
    document since <strong>all spaces in the content of a document are
    significant</strong>. If you build a tree from the API and want
    indentation:</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 your
        content <strong>modifying the content of your document in the
        process</strong>. The result may not be what you expect. There is
        <strong>NO</strong> way to guarantee that such a modification won't
        affect 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 function
    pxmlDoc=xmlParseFile(...);</em></p>
    <p><em>I want to the get the content of the first node (node with the
    CommFlag="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 with
    the formatting spaces which are part of the document but that people tend
    to 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 its
    use should be limited to cases where you are certain there is no
    mixed-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 a
    libxml2 development environment. Either switch back to libxml v1 devel or
    even 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 libxml
    and 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 to
    a 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 send
    patches.</p>
  </li>
  <li><em>Where can I get more examples and information than provided on the
    web page?</em>
    <p>Ideally a libxml2 book would be nice. I have no such plan ... But you
    can:</p>
    <ul>
      <li>check more deeply the <a href="html/libxml-lib.html">existing
        generated doc</a></li>
      <li>have a look at <a href="examples/index.html">the set of
        examples</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 the
        use 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 project
        could cure this :-)</p>
      </li>
      <li><a
        href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Browse
        the libxml2 source</a> , I try to write code as clean and documented
        as possible, so looking at it may be helpful. In particular the code
        of xmllint.c and of the various testXXX.c test programs should
        provide 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 number
    of platforms, including embedded systems. I don't intend to convert to
    C++.</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 at
    initial parsing time or documents which have been built from scratch
    using 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 existing
    document:</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 before
    passing them to the API.  This can be accomplished with the iconv library
    for 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 up
  information.</li>
  <li>Check the <a href="FAQ.html">FAQ.</a></li>
  <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
    documentation</a> automatically extracted from code comments.</li>
  <li>Look at the documentation about <a href="encoding.html">libxml
    internationalization support</a>.</li>
  <li>This page provides a global overview and <a href="example.html">some
    examples</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 nice
    documentation</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 article
    for IBM developerWorks</a> about using libxml.</li>
  <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
    file</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 should
    really 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 a
point of fixing them in a timely fashion. The best way to report a bug is to
use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Gnome
bug tracking database</a> (make sure to use the "libxml2" module name). I
look at reports there regularly and it's good to have a reminder when a bug
is 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 on
irc.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 the
mailing-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 and
follow the instructions. <strong>Do not send code, I won't debug it</strong>
(but patches are really appreciated!).</p>

<p>Check the following <strong><span style="color: #FF0000">before
posting</span></strong>:</p>
<ul>
  <li>Read the <a href="FAQ.html">FAQ</a> and <a href="search.php">use the
    search engine</a> to get information related to your problem.</li>
  <li>Make sure you are <a href="ftp://xmlsoft.org/">using a recent
    version</a>, and that the problem still shows up in a recent version.</li>
  <li>Check the <a href="http://mail.gnome.org/archives/xml/">list
    archives</a> to see if the problem was reported already. In this case
    there is probably a fix available, similarly check the <a
    href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">registered
    open bugs</a>.</li>
  <li>Make sure you can reproduce the bug with xmllint or one of the test
    programs found in source in the distribution.</li>
  <li>Please send the command showing the error as well as the input (as an
    attachment)</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 libxml
related I will approve it. Please do not send mail to me directly, it makes
things really hard to track and in some cases I am not the best person to
answer 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 to
    the list or on bugzilla</span> in case of problems, so that the Question
    and Answers can be shared publicly. Failing to do so carries the implicit
    message "I want free support but I don't want to share the benefits with
    others" and is not welcome. I will automatically Carbon-Copy the
    xml@gnome.org mailing list for any technical reply made about libxml2 or
    libxslt.</li>
  <li>There is <span style="color: #E50000">no garantee of support</span>, if
    your question remains unanswered after a week, repost it, making sure you
    gave all the detail needed and the information requested.</li>
  <li>Failing to provide information as requested or double checking first
    for prior feedback also carries the implicit message "the time of the
    library maintainers is less valuable than my time" and might not be
    welcome.</li>
</ul>

<p>Of course, bugs reported with a suggested patch for fixing them will
probably 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 actually
provide the answer. I usually send source samples when answering libxml2
usage questions. The <a
href="http://xmlsoft.org/html/book1.html">auto-generated documentation</a> is
not as polished as I would like (i need to learn more about DocBook), but
it'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 to
subscribe 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 bug
database</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 not
    be integrated in all cases but help pinpointing portability problems
  and</li>
  <li>Provide documentation fixes (either as patches to the code comments or
    as 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 and
    provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me
    </a>before to avoid synchronization problems and check that the suggested
    fix will fit in nicely :-)</li>
</ol>

<h2><a name="Downloads">Downloads</a></h2>

<p>The latest versions of libxml2 can be found on <a
href="ftp://xmlsoft.org/">xmlsoft.org</a> (<a
href="ftp://speakeasy.rpmfind.net/pub/libxml/">Seattle</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> either
as a <a href="ftp://ftp.gnome.org/pub/GNOME/sources/libxml2/2.5/">source
archive</a><!-- commenting this out because they seem to have disappeared or <a
href="ftp://ftp.gnome.org/pub/GNOME/stable/redhat/i386/libxml/">RPM
packages</a> -->
 , Antonin Sprinzl also provide <a href="ftp://gd.tuwien.ac.at/pub/libxml/">a
mirror 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>Binary ports:</p>
<ul>
  <li>Red Hat RPMs for i386 are available directly on <a
    href="ftp://xmlsoft.org/">xmlsoft.org</a>, the source RPM will compile on
    any architecture supported by Red Hat.</li>
  <li><p><a href="mailto:igor@zlatkovic.com">Igor  Zlatkovic</a></p>
    is now the maintainer of the Windows port, <a
    href="http://www.zlatkovic.com/projects/libxml/index.html">he provides
    binaries</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="mailto:Steve.Ball@zveno.com">Steve Ball</a> provides <a
    href="http://www.zveno.com/open_source/libxml2xslt.html">Mac Os X
    binaries</a>.</li>
  <li>The HP-UX porting center provides <a
    href="http://hpux.connect.org.uk/hppd/hpux/Gnome/">HP-UX binaries</a></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 gnome-xml <a
    href="ftp://xmlsoft.org/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a>.</li>
  <li>Docs, content of the web site, the list archive included <a
    href="ftp://xmlsoft.org/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 another
platform,  get in touch with me to upload the package, wrappers for various
languages have been provided, and can be found in the <a
href="contribs.html">contrib section</a></p>

<p>Libxml2 is also available from CVS:</p>
<ul>
  <li><p>The <a
    href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Gnome
    CVS base</a>. Check the <a
    href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a>
    page; the CVS module is <b>gnome-xml</b>.</p>
  </li>
  <li>The <strong>libxslt</strong> module is also present there</li>
</ul>

<h2><a name="News">News</a></h2>

<h3>CVS only : check the <a
href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
for a really accurate description</h3>

<p>Items not finished and worked on, get in touch with the list if you want
to test those</p>
<ul>
  <li>More testing on RelaxNG</li>
  <li>Finishing up <a href="http://www.w3.org/TR/xmlschema-1/">XML
  Schemas</a></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, Dodji
    Seketeli, 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 serialization
    cleanups, XML_GET_LINE macro, memory debug when using threads (William
    Brack), serialization of attributes and entities content, xmlWriter
    (Daniel Schulman)</li>
  <li>XInclude bugfix, new APIs and update to the last version including the
    namespace change.</li>
  <li>XML Schemas improvements: include (Robert Stepanek), import and
    namespace handling, fixed the regression tests troubles, added examples
    based on Eric van der Vlist book, regexp fixes </li>
  <li>preliminary pattern support for streaming (needed for schemas
    constraints), added xmlTextReaderPreservePattern() to collect subdocument
    when 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 xmlReadxxx
  functions</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 XML
    serializer)</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, Igor
    Zlatkovic)</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 (Graham
  Bennett)</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, serializing
    Document 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 lot
    of 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 small
    text 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 memory
    allocations 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 be
    intercepted at a structured level, with precise information
  available.</li>
  <li>New simpler and more generic XML and HTML parser APIs, allowing to
    easilly modify the parsing options and reuse parser context for multiple
    consecutive documents.</li>
  <li>Similar new APIs for the xmlReader, for options and reuse, provided new
    functions to access content as const strings, use them for Python
  bindings</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 PSVI
    extensions, generation of character ranges to be checked with faster
    algorithm (William),  xmlParserMaxDepth (Crutcher Dunnavant), buffer
    access</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-Type
    and charset informations if available.</li>
  <li>Relax-NG: bug fixes including the one reported by Martijn Faassen and
    zeroOrMore, better error reporting.</li>
  <li>Python bindings (St