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   10 </style><title>Catalog support</title></head><body bgcolor="#8b7765" text="#000000" link="#a06060" vlink="#000000"><table border="0" width="100%" cellpadding="5" cellspacing="0" align="center"><tr><td width="120"><a href="http://swpat.ffii.org/"><img src="epatents.png" alt="Action against software patents" /></a></td><td width="180"><a href="http://www.gnome.org/"><img src="gnome2.png" alt="Gnome2 Logo" /></a><a href="http://www.w3.org/Status"><img src="w3c.png" alt="W3C Logo" /></a><a href="http://www.redhat.com/"><img src="redhat.gif" alt="Red Hat Logo" /></a><div align="left"><a href="http://xmlsoft.org/"><img src="Libxml2-Logo-180x168.gif" alt="Made with Libxml2 Logo" /></a></div></td><td><table border="0" width="90%" cellpadding="2" cellspacing="0" align="center" bgcolor="#000000"><tr><td><table width="100%" border="0" cellspacing="1" cellpadding="3" bgcolor="#fffacd"><tr><td align="center"><h1>The XML C parser and toolkit of Gnome</h1><h2>Catalog support</h2></td></tr></table></td></tr></table></td></tr></table><table border="0" cellpadding="4" cellspacing="0" width="100%" align="center"><tr><td bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td valign="top" width="200" bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="1" width="100%" bgcolor="#000000"><tr><td><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Main Menu</b></center></td></tr><tr><td bgcolor="#fffacd"><form action="search.php" enctype="application/x-www-form-urlencoded" method="get"><input name="query" type="text" size="20" value="" /><input name="submit" type="submit" value="Search ..." /></form><ul><li><a href="index.html">Home</a></li><li><a href="html/index.html">Reference Manual</a></li><li><a href="intro.html">Introduction</a></li><li><a href="FAQ.html">FAQ</a></li><li><a href="docs.html" style="font-weight:bold">Developer Menu</a></li><li><a href="bugs.html">Reporting bugs and getting help</a></li><li><a href="help.html">How to help</a></li><li><a href="downloads.html">Downloads</a></li><li><a href="news.html">Releases</a></li><li><a href="XMLinfo.html">XML</a></li><li><a href="XSLT.html">XSLT</a></li><li><a href="xmldtd.html">Validation &amp; DTDs</a></li><li><a href="encoding.html">Encodings support</a></li><li><a href="catalog.html">Catalog support</a></li><li><a href="namespaces.html">Namespaces</a></li><li><a href="contribs.html">Contributions</a></li><li><a href="examples/index.html" style="font-weight:bold">Code Examples</a></li><li><a href="html/index.html" style="font-weight:bold">API Menu</a></li><li><a href="guidelines.html">XML Guidelines</a></li><li><a href="ChangeLog.html">Recent Changes</a></li></ul></td></tr></table><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Related links</b></center></td></tr><tr><td bgcolor="#fffacd"><ul><li><a href="http://mail.gnome.org/archives/xml/">Mail archive</a></li><li><a href="http://xmlsoft.org/XSLT/">XSLT libxslt</a></li><li><a href="http://phd.cs.unibo.it/gdome2/">DOM gdome2</a></li><li><a href="http://www.aleksey.com/xmlsec/">XML-DSig xmlsec</a></li><li><a href="ftp://xmlsoft.org/">FTP</a></li><li><a href="http://www.zlatkovic.com/projects/libxml/">Windows binaries</a></li><li><a href="http://opencsw.org/packages/libxml2">Solaris binaries</a></li><li><a href="http://www.explain.com.au/oss/libxml2xslt.html">MacOsX binaries</a></li><li><a href="http://lxml.de/">lxml Python bindings</a></li><li><a href="http://cpan.uwinnipeg.ca/dist/XML-LibXML">Perl bindings</a></li><li><a href="http://libxmlplusplus.sourceforge.net/">C++ bindings</a></li><li><a href="http://www.zend.com/php5/articles/php5-xmlphp.php#Heading4">PHP bindings</a></li><li><a href="http://sourceforge.net/projects/libxml2-pas/">Pascal bindings</a></li><li><a href="http://libxml.rubyforge.org/">Ruby bindings</a></li><li><a href="http://tclxml.sourceforge.net/">Tcl bindings</a></li><li><a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Bug Tracker</a></li></ul></td></tr></table></td></tr></table></td><td valign="top" bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="1" width="100%"><tr><td><table border="0" cellspacing="0" cellpadding="1" width="100%" bgcolor="#000000"><tr><td><table border="0" cellpadding="3" cellspacing="1" width="100%"><tr><td bgcolor="#fffacd"><p>Table of Content:</p><ol>
   11   <li><a href="General2">General overview</a></li>
   12   <li><a href="#definition">The definition</a></li>
   13   <li><a href="#Simple">Using catalogs</a></li>
   14   <li><a href="#Some">Some examples</a></li>
   15   <li><a href="#reference">How to tune  catalog usage</a></li>
   16   <li><a href="#validate">How to debug catalog processing</a></li>
   17   <li><a href="#Declaring">How to create and maintain catalogs</a></li>
   18   <li><a href="#implemento">The implementor corner quick review of the
   19   API</a></li>
   20   <li><a href="#Other">Other resources</a></li>
   21 </ol><h3><a name="General2" id="General2">General overview</a></h3><p>What is a catalog? Basically it's a lookup mechanism used when an entity
   22 (a file or a remote resource) references another entity. The catalog lookup
   23 is inserted between the moment the reference is recognized by the software
   24 (XML parser, stylesheet processing, or even images referenced for inclusion
   25 in a rendering) and the time where loading that resource is actually
   26 started.</p><p>It is basically used for 3 things:</p><ul>
   27   <li>mapping from "logical" names, the public identifiers and a more
   28     concrete name usable for download (and URI). For example it can associate
   29     the logical name
   30     <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
   31     <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be
   32     downloaded</p>
   33     <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
   34   </li>
   35   <li>remapping from a given URL to another one, like an HTTP indirection
   36     saying that
   37     <p>"http://www.oasis-open.org/committes/tr.xsl"</p>
   38     <p>should really be looked at</p>
   39     <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
   40   </li>
   41   <li>providing a local cache mechanism allowing to load the entities
   42     associated to public identifiers or remote resources, this is a really
   43     important feature for any significant deployment of XML or SGML since it
   44     allows to avoid the aleas and delays associated to fetching remote
   45     resources.</li>
   46 </ul><h3><a name="definition" id="definition">The definitions</a></h3><p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p><ul>
   47   <li>the older SGML catalogs, the official spec is  SGML Open Technical
   48     Resolution TR9401:1997, but is better understood by reading <a href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from
   49     James Clark. This is relatively old and not the preferred mode of
   50     operation of libxml.</li>
   51   <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML
   52     Catalogs</a> is far more flexible, more recent, uses an XML syntax and
   53     should scale quite better. This is the default option of libxml.</li>
   54 </ul><p></p><h3><a name="Simple" id="Simple">Using catalog</a></h3><p>In a normal environment libxml2 will by default check the presence of a
   55 catalog in /etc/xml/catalog, and assuming it has been correctly populated,
   56 the processing is completely transparent to the document user. To take a
   57 concrete example, suppose you are authoring a DocBook document, this one
   58 starts with the following DOCTYPE definition:</p><pre>&lt;?xml version='1.0'?&gt;
   59 &lt;!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
   60           "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"&gt;</pre><p>When validating the document with libxml, the catalog will be
   61 automatically consulted to lookup the public identifier "-//Norman Walsh//DTD
   62 DocBk XML V3.1.4//EN" and the system identifier
   63 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have
   64 been installed on your system and the catalogs actually point to them, libxml
   65 will fetch them from the local disk.</p><p style="font-size: 10pt"><strong>Note</strong>: Really don't use this
   66 DOCTYPE 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 an
   67 entity, this includes DTD, external parsed entities, stylesheets, etc ... If
   68 your system is correctly configured all the authoring phase and processing
   69 should use only local files, even if your document stays portable because it
   70 uses the canonical public and system ID, referencing the remote document.</p><h3><a name="Some" id="Some">Some examples:</a></h3><p>Here is a couple of fragments from XML Catalogs used in libxml2 early
   71 regression tests in <code>test/catalogs</code> :</p><pre>&lt;?xml version="1.0"?&gt;
   72 &lt;!DOCTYPE catalog PUBLIC 
   73    "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
   74    "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
   75 &lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
   76   &lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
   77    uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
   78 ...</pre><p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are
   79 written in XML,  there is a specific namespace for catalog elements
   80 "urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this
   81 catalog is a <code>public</code> mapping it allows to associate a Public
   82 Identifier with an URI.</p><pre>...
   83     &lt;rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
   84                    rewritePrefix="file:///usr/share/xml/docbook/"/&gt;
   85 ...</pre><p>A <code>rewriteSystem</code> is a very powerful instruction, it says that
   86 any URI starting with a given prefix should be looked at another  URI
   87 constructed by replacing the prefix with an new one. In effect this acts like
   88 a cache system for a full area of the Web. In practice it is extremely useful
   89 with a file prefix if you have installed a copy of those resources on your
   90 local system.</p><pre>...
   91 &lt;delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
   92                 catalog="file:///usr/share/xml/docbook.xml"/&gt;
   93 &lt;delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
   94                 catalog="file:///usr/share/xml/docbook.xml"/&gt;
   95 &lt;delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
   96                 catalog="file:///usr/share/xml/docbook.xml"/&gt;
   97 &lt;delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
   98                 catalog="file:///usr/share/xml/docbook.xml"/&gt;
   99 &lt;delegateURI uriStartString="http://www.oasis-open.org/docbook/"
  100                 catalog="file:///usr/share/xml/docbook.xml"/&gt;
  101 ...</pre><p>Delegation is the core features which allows to build a tree of catalogs,
  102 easier to maintain than a single catalog, based on Public Identifier, System
  103 Identifier or URI prefixes it instructs the catalog software to look up
  104 entries in another resource. This feature allow to build hierarchies of
  105 catalogs, the set of entries presented should be sufficient to redirect the
  106 resolution of all DocBook references to the specific catalog in
  107 <code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all
  108 references for DocBook 4.2.1 to a specific catalog installed at the same time
  109 as the DocBook resources on the local machine.</p><h3><a name="reference" id="reference">How to tune catalog usage:</a></h3><p>The user can change the default catalog behaviour by redirecting queries
  110 to its own set of catalogs, this can be done by setting the
  111 <code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an
  112 empty one should deactivate loading the default <code>/etc/xml/catalog</code>
  113 default catalog</p><h3><a name="validate" id="validate">How to debug catalog processing:</a></h3><p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will
  114 make libxml2 output debugging information for each catalog operations, for
  115 example:</p><pre>orchis:~/XML -&gt; xmllint --memory --noout test/ent2
  116 warning: failed to load external entity "title.xml"
  117 orchis:~/XML -&gt; export XML_DEBUG_CATALOG=
  118 orchis:~/XML -&gt; xmllint --memory --noout test/ent2
  119 Failed to parse catalog /etc/xml/catalog
  120 Failed to parse catalog /etc/xml/catalog
  121 warning: failed to load external entity "title.xml"
  122 Catalogs cleanup
  123 orchis:~/XML -&gt; </pre><p>The test/ent2 references an entity, running the parser from memory makes
  124 the base URI unavailable and the the "title.xml" entity cannot be loaded.
  125 Setting up the debug environment variable allows to detect that an attempt is
  126 made to load the <code>/etc/xml/catalog</code> but since it's not present the
  127 resolution fails.</p><p>But the most advanced way to debug XML catalog processing is to use the
  128 <strong>xmlcatalog</strong> command shipped with libxml2, it allows to load
  129 catalogs and make resolution queries to see what is going on. This is also
  130 used for the regression tests:</p><pre>orchis:~/XML -&gt; ./xmlcatalog test/catalogs/docbook.xml \
  131                    "-//OASIS//DTD DocBook XML V4.1.2//EN"
  132 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
  133 orchis:~/XML -&gt; </pre><p>For debugging what is going on, adding one -v flags increase the verbosity
  134 level to indicate the processing done (adding a second flag also indicate
  135 what elements are recognized at parsing):</p><pre>orchis:~/XML -&gt; ./xmlcatalog -v test/catalogs/docbook.xml \
  136                    "-//OASIS//DTD DocBook XML V4.1.2//EN"
  137 Parsing catalog test/catalogs/docbook.xml's content
  138 Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
  139 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
  140 Catalogs cleanup
  141 orchis:~/XML -&gt; </pre><p>A shell interface is also available to debug and process multiple queries
  142 (and for regression tests):</p><pre>orchis:~/XML -&gt; ./xmlcatalog -shell test/catalogs/docbook.xml \
  143                    "-//OASIS//DTD DocBook XML V4.1.2//EN"
  144 &gt; help   
  145 Commands available:
  146 public PublicID: make a PUBLIC identifier lookup
  147 system SystemID: make a SYSTEM identifier lookup
  148 resolve PublicID SystemID: do a full resolver lookup
  149 add 'type' 'orig' 'replace' : add an entry
  150 del 'values' : remove values
  151 dump: print the current catalog state
  152 debug: increase the verbosity level
  153 quiet: decrease the verbosity level
  154 exit:  quit the shell
  155 &gt; public "-//OASIS//DTD DocBook XML V4.1.2//EN"
  156 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
  157 &gt; quit
  158 orchis:~/XML -&gt; </pre><p>This should be sufficient for most debugging purpose, this was actually
  159 used heavily to debug the XML Catalog implementation itself.</p><h3><a name="Declaring" id="Declaring">How to create and maintain</a> catalogs:</h3><p>Basically XML Catalogs are XML files, you can either use XML tools to
  160 manage them or use  <strong>xmlcatalog</strong> for this. The basic step is
  161 to create a catalog the -create option provide this facility:</p><pre>orchis:~/XML -&gt; ./xmlcatalog --create tst.xml
  162 &lt;?xml version="1.0"?&gt;
  163 &lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
  164          "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
  165 &lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
  166 orchis:~/XML -&gt; </pre><p>By default xmlcatalog does not overwrite the original catalog and save the
  167 result on the standard output, this can be overridden using the -noout
  168 option. The <code>-add</code> command allows to add entries in the
  169 catalog:</p><pre>orchis:~/XML -&gt; ./xmlcatalog --noout --create --add "public" \
  170   "-//OASIS//DTD DocBook XML V4.1.2//EN" \
  171   http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
  172 orchis:~/XML -&gt; cat tst.xml
  173 &lt;?xml version="1.0"?&gt;
  174 &lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
  175   "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
  176 &lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
  177 &lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
  178         uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
  179 &lt;/catalog&gt;
  180 orchis:~/XML -&gt; </pre><p>The <code>-add</code> option will always take 3 parameters even if some of
  181 the XML Catalog constructs (like nextCatalog) will have only a single
  182 argument, just pass a third empty string, it will be ignored.</p><p>Similarly the <code>-del</code> option remove matching entries from the
  183 catalog:</p><pre>orchis:~/XML -&gt; ./xmlcatalog --del \
  184   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
  185 &lt;?xml version="1.0"?&gt;
  186 &lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
  187     "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
  188 &lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
  189 orchis:~/XML -&gt; </pre><p>The catalog is now empty. Note that the matching of <code>-del</code> is
  190 exact and would have worked in a similar fashion with the Public ID
  191 string.</p><p>This is rudimentary but should be sufficient to manage a not too complex
  192 catalog tree of resources.</p><h3><a name="implemento" id="implemento">The implementor corner quick review of the
  193 API:</a></h3><p>First, and like for every other module of libxml, there is an
  194 automatically generated <a href="html/libxml-catalog.html">API page for
  195 catalog 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 that
  196 applications really need access to it since it is the default behaviour of
  197 libxml2 (Note: it is possible to completely override libxml2 default catalog
  198 by using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to
  199 plug an application specific resolver).</p><p>Basically libxml2 support 2 catalog lists:</p><ul>
  200   <li>the default one, global shared by all the application</li>
  201   <li>a per-document catalog, this one is built if the document uses the
  202     <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is
  203     associated to the parser context and destroyed when the parsing context
  204     is destroyed.</li>
  205 </ul><p>the document one will be used first if it exists.</p><h4>Initialization routines:</h4><p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be
  206 used at startup to initialize the catalog, if the catalog should be
  207 initialized with specific values xmlLoadCatalog()  or xmlLoadCatalogs()
  208 should be called before xmlInitializeCatalog() which would otherwise do a
  209 default initialization first.</p><p>The xmlCatalogAddLocal() call is used by the parser to grow the document
  210 own catalog list if needed.</p><h4>Preferences setup:</h4><p>The XML Catalog spec requires the possibility to select default
  211 preferences between  public and system delegation,
  212 xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and
  213 xmlCatalogGetDefaults() allow to control  if XML Catalogs resolution should
  214 be forbidden, allowed for global catalog, for document catalog or both, the
  215 default is to allow both.</p><p>And of course xmlCatalogSetDebug() allows to generate debug messages
  216 (through the xmlGenericError() mechanism).</p><h4>Querying routines:</h4><p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic()
  217 and xmlCatalogResolveURI() are relatively explicit if you read the XML
  218 Catalog specification they correspond to section 7 algorithms, they should
  219 also work if you have loaded an SGML catalog with a simplified semantic.</p><p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but
  220 operate on the document catalog list</p><h4>Cleanup and Miscellaneous:</h4><p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is
  221 the per-document equivalent.</p><p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the
  222 first catalog in the global list, and xmlCatalogDump() allows to dump a
  223 catalog state, those routines are primarily designed for xmlcatalog, I'm not
  224 sure that exposing more complex interfaces (like navigation ones) would be
  225 really useful.</p><p>The xmlParseCatalogFile() is a function used to load XML Catalog files,
  226 it's similar as xmlParseFile() except it bypass all catalog lookups, it's
  227 provided 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 to
  228 try to avoid troubles in multithreaded environments. The code is now thread
  229 safe assuming that the libxml2 library has been compiled with threads
  230 support.</p><p></p><h3><a name="Other" id="Other">Other resources</a></h3><p>The XML Catalog specification is relatively recent so there isn't much
  231 literature to point at:</p><ul>
  232   <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">the
  233     need for catalogs</a>, it provides a lot of context information even if
  234     I don't agree with everything presented. Norm also wrote a more recent
  235     article <a href="http://wwws.sun.com/software/xml/developers/resolver/article/">XML
  236     entities and URI resolvers</a> describing them.</li>
  237   <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML
  238     catalog proposal</a> from John Cowan</li>
  239   <li>The <a href="http://www.rddl.org/">Resource Directory Description
  240     Language</a> (RDDL) another catalog system but more oriented toward
  241     providing metadata for XML namespaces.</li>
  242   <li>the page from the OASIS Technical <a href="http://www.oasis-open.org/committees/entity/">Committee on Entity
  243     Resolution</a> who maintains XML Catalog, you will find pointers to the
  244     specification update, some background and pointers to others tools
  245     providing XML Catalog support</li>
  246   <li>There is a <a href="buildDocBookCatalog">shell script</a> to generate
  247     XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/
  248     directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on
  249     the resources found on the system. Otherwise it will just create
  250     ~/xmlcatalog and ~/dbkxmlcatalog and doing:
  251     <p><code>export XML_CATALOG_FILES=$HOME/xmlcatalog</code></p>
  252     <p>should allow to process DocBook documentations without requiring
  253     network accesses for the DTD or stylesheets</p>
  254   </li>
  255   <li>I have uploaded <a href="ftp://xmlsoft.org/libxml2/test/dbk412catalog.tar.gz">a
  256     small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems
  257     to work fine for me too</li>
  258   <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog
  259     manual page</a></li>
  260 </ul><p>If you have suggestions for corrections or additions, simply contact
  261 me:</p><p><a href="bugs.html">Daniel Veillard</a></p></td></tr></table></td></tr></table></td></tr></table></td></tr></table></td></tr></table></body></html>