INTRODUCTION
============

This module implements a Perl interface to the Gnome libxml2 library which
provides interfaces for parsing and manipulating XML files. This module allows
Perl programmers to make use of the highly capable validating XML parser and
the high performance DOM implementation.


IMPORTANT NOTES
===============

XML::LibXML was almost entirely reimplemented between version 1.40 to version
1.49. This may cause problems on some production machines. With version 1.50 a
lot of compatibility fixes were applied, so programs written for XML::LibXML
1.40 or less should run with version 1.50 again.

In 1.59, a new callback API was introduced. This new API is not compatible with
the previous one. See XML::LibXML::InputCallback manual page for details.

In 1.61 the XML::LibXML::XPathContext module, previously distributed
separately, was merged in.

An experimental support for Perl threads introduced in 1.66 has been replaced
in 1.67.


DEPENDENCIES
============

Prior to installation you MUST have installed the libxml2 library. You can get
the latest libxml2 version from

http://xmlsoft.org/

Without libxml2 installed this module will neither build nor run.

Also XML::LibXML requires the following packages:

   o XML::SAX - base class for SAX parsers
   o XML::NamespaceSupport - namespace support for SAX parsers

These packages are required. If one is missing some tests will fail.

Again, libxml2 is required to make XML::LibXML work. The library is not just
required to build XML::LibXML, it has to be accessible during run-time as well.
Because of this you need to make sure libxml2 is installed properly. To test
this, run the xmllint program on your system. xmllint is shipped with libxml2
and therefore should be available. For building the module you will also need
the header file for libxml2, which in binary (.rpm,.deb) etc. distributions
usually dwell in a package named libxml2-devel or similar.


INSTALLATION
============

(These instructions are for UNIX and GNU/Linux systems. For MSWin32, See Notes
for Microsoft Windows below.)

To install XML::LibXML just follow the standard installation routine for Perl
modules:

   1 perl Makefile.PL
   2 make
   3 make test
   4 make install # as superuser

Note that XML::LibXML is an XS based Perl extension and you need a C compiler
to build it.

Note also that you should rebuild XML::LibXML if you upgrade libxml2 in order
to avoid problems with possible binary incompatibilities between releases of
the library.


Notes on libxml2 versions
=========================

XML::LibXML requires at least libxml2 2.6.16 to compile and pass all tests and
at least 2.6.21 is required for XML::LibXML::Reader. For some older OS versions
this means that an update of the pre-built packages is required.

Although libxml2 claims binary compatibility between its patch levels, it is a
good idea to recompile XML::LibXML and run its tests after an upgrade of
libxml2.

If your libxml2 installation is not within your $PATH, you can pass the
XMLPREFIX=$YOURLIBXMLPREFIX parameter to Makefile.PL determining the correct
libxml2 version in use. e.g.

>  perl Makefile.PL XMLPREFIX=/usr/brand-new

will ask '/usr/brand-new/bin/xml2-config' about your real libxml2
configuration.

Try to avoid setting INC and LIBS directly on the command-line, for if used,
Makefile.PL does not check the libxml2 version for compatibility with
XML::LibXML.


Which version of libxml2 should be used?
========================================

XML::LibXML is tested against a couple versions of libxml2 before it is
released. Thus there are versions of libxml2 that are known not to work
properly with XML::LibXML. The Makefile.PL keeps a blacklist of the
incompatible libxml2 versions.

If Makefile.PL detects one of the incompatible versions, it notifies the user.
It may still happen that XML::LibXML builds and pass its tests with such a
version, but that does not mean everything is OK. There will be no support at
all for blacklisted versions!

As of XML::LibXML 1.61, only versions 2.6.16 and higher are supported.
XML::LibXML will probably not compile with earlier libxml2 versions than 2.5.6.
Versions prior to 2.6.8 are known to be broken for various reasons, versions
prior to 2.1.16 exhibit problems with namespaced attributes and do not
therefore pass XML::LibXML regression tests.

It may happen that an unsupported version of libxml2 passes all tests under
certain conditions. This is no reason to assume that it shall work without
problems. If Makefile.PL marks a version of libxml2 as incompatible or broken
it is done for a good reason.


Notes for Microsoft Windows
===========================

Thanks to Randy Kobes there is a pre-compiled PPM package available on

http://theoryx5.uwinnipeg.ca/ppmpackages/

Usually it takes a little time to build the package for the latest release.

If you want to build XML::LibXML on Windows from source, you can use the
following instructions contributed by Christopher J. Madsen:

These instructions assume that you already have your system set up to compile
modules that use C components.

First, get the libxml2 binaries from http://xmlsoft.org/sources/win32/
(currently also available at http://www.zlatkovic.com/pub/libxml/).

You need:

>   iconv-VERSION.win32.zip
>   libxml2-VERSION.win32.zip
>   zlib-VERSION.win32.zip

Download the latest version of each. (Each package will probably have a
different version.) When you extract them, you'll get directories named
iconv-VERSION.win32, libxml2-VERSION.win32, and zlib-VERSION.win32, each
containing bin, lib, and include directories.

Combine all the bin, include, and lib directories under c:\Prog\LibXML. (You
can use any directory you prefer; just adjust the instructions accordingly.)

Get the latest version of XML-LibXML from CPAN. Extract it.

Issue these commands in the XML-LibXML-VERSION directory:

>   perl Makefile.PL INC=-Ic:\Prog\LibXML\include LIBS=-Lc:\Prog\LibXML\lib
>   nmake
>   copy c:\Prog\LibXML\bin\*.dll blib\arch\auto\XML\LibXML
>   nmake test
>   nmake install

(Note: Some systems use dmake instead of nmake.)

By copying the libxml2 DLLs to the arch directory, you help avoid conflicts
with other programs you may have installed that use other (possibly
incompatible) versions of those DLLs.


Notes for Mac OS X
==================

Due refactoring the module, XML::LibXML will not run with some earlier versions
of Mac OS X. It appears that this is related to special linker options for that
OS prior to version 10.2.2. Since the developers do not have full access to
this OS, help/ patches from OS X gurus are highly appreciated.

It is confirmed that XML::LibXML builds and runs without problems since Mac OS
X 10.2.6.


Notes for HPUX
==============

XML::LibXML requires libxml2 2.6.16 or later. There may not exist a usable
binary libxml2 package for HPUX and XML::LibXML. If HPUX cc does not compile
libxml2 correctly, you will be forced to recompile perl with gcc (unless you
have already done that).

Additionally I received the following Note from Rozi Kovesdi:

> Here is my report if someone else runs into the same problem:
>
> Finally I am done with installing all the libraries and XML Perl
> modules
>
> The combination that worked best for me was:
> gcc
> GNU make
>
> Most importantly - before trying to install Perl modules that depend on
> libxml2:
>
> must set SHLIB_PATH  to include  the path to  libxml2 shared library
>
> assuming that you used the default:
>
> export  SHLIB=/usr/local/lib
>
> also, make sure that the config  files have execute permission:
>
> /usr/local/bin/xml2-config
> /usr/local/bin/xslt-config
>
> they did not have +x after they were installed by 'make install'
> and it took me a while to realize that this was my problem
>
> or one can use:
>
> perl Makefile.PL LIBS='-L/path/to/lib' INC='-I/path/to/include'


CONTACT
=======

For bug reports, please use the CPAN request tracker on
http://rt.cpan.org/NoAuth/Bugs.html?Dist=XML-LibXML

For suggestions etc. you may contact the maintainer directly at "pajas at ufal
dot mff dot cuni dot cz", but in general, it is recommended to use the mailing
list given below.

For suggestions etc., and other issues related to XML::LibXML you may use the
perl XML mailing list (perl-xml@listserv.ActiveState.com), where most
XML-related Perl modules are discussed. In case of problems you should check
the archives of that list first. Many problems are already discussed there. You
can find the list's archives and subscription options at
http://aspn.activestate.com/ASPN/Mail/Browse/Threaded/perl-xml


PACKAGE HISTORY
===============

Version < 0.98 were maintained by Matt Sergeant

0.98 > Version > 1.49 were maintained by Matt Sergeant and Christian Glahn

Versions >= 1.49 are maintained by Christian Glahn

Versions > 1.56 are co-maintained by Petr Pajas

Versions >= 1.59 are provisionally maintained by Petr Pajas


PATCHES AND DEVELOPER VERSION
=============================

As XML::LibXML is open source software, help and patches are appreciated. If
you find a bug in the current release, make sure this bug still exists in the
developer version of XML::LibXML. This version can be downloaded from its
Mercurial repository. For more information about that, see:

http://bitbucket.org/shlomif/perl-xml-libxml

Please consider all regression tests as correct. If any test fails it is most
certainly related to a bug.

If you find documentation bugs, please fix them in the libxml.dbk file, stored
in the docs directory.


KNOWN ISSUES
============

The push-parser implementation causes memory leaks.

