doc/FAQ.html - platform/external/libxml2 - Gitiles

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 <body bgcolor="#ffffff">
 <h1 align="center">Libxml Frequently Asqued Questions</h1>

 <p>Location: <a
 href="http://xmlsoft.org/FAQ.html">http://xmlsoft.org/FAQ.html</a></p>

 <p>Libxml home page: <a href="http://xmlsoft.org/">http://xmlsoft.org/</a></p>

 <p>Mailing-list archive:  <a
 href="http://xmlsoft.org/messages/">http://xmlsoft.org/messages/</a></p>

 <p>Version: $Revision$</p>

 <p>Table of Content:</p>
 <ul>
   <li><a href="#Licence">Licence(s)</a></li>
   <li><a href="#Installati">Installation</a></li>
   <li><a href="#Compilatio">Compilation</a></li>
   <li><a href="#Developper">Developper corner</a></li>
 </ul>

 <h2><a name="Licence">Licence</a>(s)</h2>
 <ol>
   <li><em>Licensing Terms for libxml</em>
     <p>libxml is released under 2 (compatible) licences:</p>
     <ul>
       <li>the <a href="http://www.gnu.org/copyleft/lgpl.html">LGPL</a>: GNU
         Library General Public License</li>
       <li>the <a
         href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C
         IPR</a>: very similar to the XWindow licence</li>
     </ul>
   </li>
   <li><em>Can I embed libxml in a proprietary application ?</em>
     <p>Yes. The W3C IPR allows you to also keep proprietary the changes you
     made to libxml, but it would be graceful to provide back bugfixes and
     improvements as patches for possible incorporation in the main
     developement tree</p>
   </li>
 </ol>

 <h2><a name="Installati">Installation</a></h2>
 <ol>
   <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/stable/sources/libxml/">gnome.org</a></p>
     <p>Most linux and Bsd distribution includes libxml, this is probably the
     safer way for end-users</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 concerned by any existing backward compatibility with
         existing application, 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 developper and your system provides separate packaging
         for shared libraries and the development components, it is possible to
         install libxml and libxml2, and depending on your development needs
         have either <a
         href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>
         or <a
         href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>
         too</li>
       <li>If you are developping 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. Anyway the
     libxml packages provided on <a
     href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provides
     libxml.so.0</p>
   </li>
 </ol>

 <h2><a name="Compilatio">Compilation</a></h2>
 <ol>
   <li><em>What is the process to compile libxml ?</em>
     <p>As most UNIX libraries libxml 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 similar utility to
     update your list of installed shared libs.</p>
   </li>
   <li><em>What other libraries are needed to compile/install libxml ?</em>
     <p>Libxml does not requires 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 libxml will deect 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's
         included by default on recent glibc libraries, so it doesn't need to
         be installed specifically on linux. It seems it's now <a
         href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part of
         the official UNIX</a> specification, though I could not find a home
         page for the project.</li>
     </ul>
   </li>
   <li><em>The Makefile for the example gjobread is not generated</em>
     <p>This is due to a circular dependancy in automake. No solution found so
     far (if you know how to fix this the patch will be very welcome), that
     failure won't affect the actually building of the xml library. You can
     later go in and create the example Makefile by hand or reuse the
     following:</p>
     <pre>CC=gcc
         CFLAGS=`xml-config --cflags`
         LDFLAGS=`xml-config --libs`

         all: gjobread

         clean:
         &lt;TAB>@(rm -f gjobread gjobread.o)

         gjobread.o : gjobread.c
         &lt;TAB>$(CC) $(CFLAGS) -c gjobread.c

         gjobread: gjobread.o
         &lt;TAB>$(CC) -o gjobread gjobread.o $(LDFLAGS)</pre>
   </li>
   <li><em>libxml does not compile with HP-UX's optional ANSI-C compiler</em>
     <p>this is due to macro limitations. Try to add " -Wp,-H16800 -Ae" to the
     CFLAGS</p>
     <p>you can also install and use gcc instead or use a precompiled version
     of libxml, both available from the <a
     href="http://hpux.cae.wisc.edu/hppd/auto/summary_all.html">HP-UX Porting
     and Archive Centre</a></p>
   </li>
   <li><em>make check fails on some platforms</em>
     <p>Sometime 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>
   </li>
 </ol>

 <h2><a name="Developper">Developper</a> corner</h2>
 <ol>
   <li><em>I get compilation errors of existing code like when accessing
     <strong>root</strong> or <strong>childs fields</strong> of nodes</em>
     <p>You are compiling code developped for libxml version 1 and using a
     libxml2 developement 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)
     >= 1.8.8 or libxml2(-devel) >= 2.1.0</p>
   </li>
   <li><em>XPath implementation looks seriously broken</em>
     <p>True, it's incomplete and the version released in 2.0.0 was nearly
     unusable. A set of patches from <a href="http://www.picdar.co.uk/">Picdar
     Technology</a> have been integrated in 2.1.0 fixing the most nasty bugs.
     But there is still bugs and its incomplete. Patches and bug reports are
     welcome. This will be worked out, XPath implementation is not abandonned,
     just a momentary lack of time.</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/> ...</p>
     <p>Check the previous points 1/ and 2/ raised before, and send
     patches.</p>
   </li>
   <li><em>Where can I get more examples and informations than in the web
     page</em>
     <p>Ideally a libxml 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>looks for examples of use for libxml 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&dir=gnome-xml">Browse
         the libxml source</a>, I try to write code as clean and documented as
         possible, so looking at it may be helpful</li>
     </ul>
   </li>
   <li>What about C++ ?
     <p>libxml 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 provided by Ari Johnson
     &lt;ari@btigate.com> which may fullfill your needs:</p>
     <p>Website: <a
     href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
     <p>Download: <a
     href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
   </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 who have been built from scratch using
     the API. Use the <a
     href="http://xmlsoft.org/html/gnome-xml-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->name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */

         doc->intSubset = dtd;
         if (doc->children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
         else xmlAddPrevSibling(doc->children, (xmlNodePtr)dtd);
           </pre>
   </li>
   <li>etc ...</li>
 </ol>

 <p><a href="mailto:Daniel.Veillard@w3.org">Daniel Veillard</a></p>

 <p>$Id$</p>
 </body>
 </html>
	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
	"http://www.w3.org/TR/REC-html40/loose.dtd">
	<html>
	<head>
	<title>Libxml Frequently asqued Questions</title>
	<meta name="GENERATOR" content="amaya V2.1">
	<meta http-equiv="Content-Type" content="text/html">
	</head>

	<body bgcolor="#ffffff">
	<h1 align="center">Libxml Frequently Asqued Questions</h1>

	<p>Location: <a
	href="http://xmlsoft.org/FAQ.html">http://xmlsoft.org/FAQ.html</a></p>

	<p>Libxml home page: <a href="http://xmlsoft.org/">http://xmlsoft.org/</a></p>

	<p>Mailing-list archive: <a
	href="http://xmlsoft.org/messages/">http://xmlsoft.org/messages/</a></p>

	<p>Version: $Revision$</p>

	<p>Table of Content:</p>
	<ul>
	<li><a href="#Licence">Licence(s)</a></li>
	<li><a href="#Installati">Installation</a></li>
	<li><a href="#Compilatio">Compilation</a></li>
	<li><a href="#Developper">Developper corner</a></li>
	</ul>

	<h2><a name="Licence">Licence</a>(s)</h2>
	<ol>
	<li><em>Licensing Terms for libxml</em>
	<p>libxml is released under 2 (compatible) licences:</p>
	<ul>
	<li>the <a href="http://www.gnu.org/copyleft/lgpl.html">LGPL</a>: GNU
	Library General Public License</li>
	<li>the <a
	href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C
	IPR</a>: very similar to the XWindow licence</li>
	</ul>
	</li>
	<li><em>Can I embed libxml in a proprietary application ?</em>
	<p>Yes. The W3C IPR allows you to also keep proprietary the changes you
	made to libxml, but it would be graceful to provide back bugfixes and
	improvements as patches for possible incorporation in the main
	developement tree</p>
	</li>
	</ol>

	<h2><a name="Installati">Installation</a></h2>
	<ol>
	<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/stable/sources/libxml/">gnome.org</a></p>
	<p>Most linux and Bsd distribution includes libxml, this is probably the
	safer way for end-users</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 concerned by any existing backward compatibility with
	existing application, 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 developper and your system provides separate packaging
	for shared libraries and the development components, it is possible to
	install libxml and libxml2, and depending on your development needs
	have either <a
	href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>
	or <a
	href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>
	too</li>
	<li>If you are developping 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. Anyway the
	libxml packages provided on <a
	href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provides
	libxml.so.0</p>
	</li>
	</ol>

	<h2><a name="Compilatio">Compilation</a></h2>
	<ol>
	<li><em>What is the process to compile libxml ?</em>
	<p>As most UNIX libraries libxml 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 similar utility to
	update your list of installed shared libs.</p>
	</li>
	<li><em>What other libraries are needed to compile/install libxml ?</em>
	<p>Libxml does not requires 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 libxml will deect 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's
	included by default on recent glibc libraries, so it doesn't need to
	be installed specifically on linux. It seems it's now <a
	href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part of
	the official UNIX</a> specification, though I could not find a home
	page for the project.</li>
	</ul>
	</li>
	<li><em>The Makefile for the example gjobread is not generated</em>
	<p>This is due to a circular dependancy in automake. No solution found so
	far (if you know how to fix this the patch will be very welcome), that
	failure won't affect the actually building of the xml library. You can
	later go in and create the example Makefile by hand or reuse the
	following:</p>
	<pre>CC=gcc
	CFLAGS=`xml-config --cflags`
	LDFLAGS=`xml-config --libs`

	all: gjobread

	clean:
	<TAB>@(rm -f gjobread gjobread.o)

	gjobread.o : gjobread.c
	<TAB>$(CC) $(CFLAGS) -c gjobread.c

	gjobread: gjobread.o
	<TAB>$(CC) -o gjobread gjobread.o $(LDFLAGS)</pre>
	</li>
	<li><em>libxml does not compile with HP-UX's optional ANSI-C compiler</em>
	<p>this is due to macro limitations. Try to add " -Wp,-H16800 -Ae" to the
	CFLAGS</p>
	<p>you can also install and use gcc instead or use a precompiled version
	of libxml, both available from the <a
	href="http://hpux.cae.wisc.edu/hppd/auto/summary_all.html">HP-UX Porting
	and Archive Centre</a></p>
	</li>
	<li><em>make check fails on some platforms</em>
	<p>Sometime 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>
	</li>
	</ol>

	<h2><a name="Developper">Developper</a> corner</h2>
	<ol>
	<li><em>I get compilation errors of existing code like when accessing
	<strong>root</strong> or <strong>childs fields</strong> of nodes</em>
	<p>You are compiling code developped for libxml version 1 and using a
	libxml2 developement 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)
	>= 1.8.8 or libxml2(-devel) >= 2.1.0</p>
	</li>
	<li><em>XPath implementation looks seriously broken</em>
	<p>True, it's incomplete and the version released in 2.0.0 was nearly
	unusable. A set of patches from <a href="http://www.picdar.co.uk/">Picdar
	Technology</a> have been integrated in 2.1.0 fixing the most nasty bugs.
	But there is still bugs and its incomplete. Patches and bug reports are
	welcome. This will be worked out, XPath implementation is not abandonned,
	just a momentary lack of time.</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
	<grin/> ...</p>
	<p>Check the previous points 1/ and 2/ raised before, and send
	patches.</p>
	</li>
	<li><em>Where can I get more examples and informations than in the web
	page</em>
	<p>Ideally a libxml 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>looks for examples of use for libxml 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&dir=gnome-xml">Browse
	the libxml source</a>, I try to write code as clean and documented as
	possible, so looking at it may be helpful</li>
	</ul>
	</li>
	<li>What about C++ ?
	<p>libxml 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 provided by Ari Johnson
	<ari@btigate.com> which may fullfill your needs:</p>
	<p>Website: <a
	href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
	<p>Download: <a
	href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
	</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 who have been built from scratch using
	the API. Use the <a
	href="http://xmlsoft.org/html/gnome-xml-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->name = xmlStrDup((xmlChar)"root_name"); / use the given root */

	doc->intSubset = dtd;
	if (doc->children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
	else xmlAddPrevSibling(doc->children, (xmlNodePtr)dtd);
	</pre>
	</li>
	<li>etc ...</li>
	</ol>

	<p><a href="mailto:Daniel.Veillard@w3.org">Daniel Veillard</a></p>

	<p>$Id$</p>
	</body>
	</html>