=head1 NAME

XML::LibXML::Common - Constants and Character Encoding Routines

=head1 SYNOPSIS



  use XML::LibXML::Common;

  $encodedstring = encodeToUTF8( $name_of_encoding, $sting_to_encode );
  $decodedstring = decodeFromUTF8($name_of_encoding, $string_to_decode );

=head1 DESCRIPTION

XML::LibXML::Common defines constants for all node types and provides interface
to libxml2 charset conversion functions. 

Since XML::LibXML use their own node type definitions, one may want to use
XML::LibXML::Common in its compatibility mode: 


=head2 Exporter TAGS



  use XML::LibXML::Common qw(:libxml);

C<<<<<< :libxml >>>>>> tag will use the XML::LibXML Compatibility mode, which defines the old 'XML_'
node-type definitions.



  use XML::LibXML::Common qw(:gdome);

C<<<<<< :gdome >>>>>> tag will use the XML::GDOME Compatibility mode, which defines the old 'GDOME_'
node-type definitions.



  use XML::LibXML::Common qw(:w3c);

This uses the nodetype definition names as specified for DOM.



  use XML::LibXML::Common qw(:encoding);

This tag can be used to export only the charset encoding functions of
XML::LibXML::Common. 


=head2 Exports

By default the W3 definitions as defined in the DOM specifications and the
encoding functions are exported by XML::LibXML::Common. 


=head2 Encoding functions

To encode or decode a string to or from UTF-8, XML::LibXML::Common exports two
functions, which provide interfact to the encoding support in C<<<<<< libxml2 >>>>>>. Which encodings are supported by these functions depends on how C<<<<<< libxml2 >>>>>> was compiled. UTF-16 is always supported and on most installations, ISO
encodings are supported as well. 

This interface was useful for older versions of Perl. Since Perl >= 5.8
provides similar funcions via the C<<<<<< Encode >>>>>> module, it is probably a good idea to use those instead. 

=over 4

=item encodeToUTF8

  $encodedstring = encodeToUTF8( $name_of_encoding, $sting_to_encode );

The function will convert a byte string from the specified encoding to an UTF-8
encoded character string.


=item decodeToUTF8

  $decodedstring = decodeFromUTF8($name_of_encoding, $string_to_decode );

This function converts an UTF-8 encoded character string to a specified
encoding. Note that the conversion can raise an error if the given string
contains characters that cannot be represented in the target encoding. 



=back

Both these functions report their errors on the standard error. If an error
occours the function will croak(). To catch the error information it is
required to call the encoding function from within an eval block in order to
prevent the entire script from being stopped on encoding error.


=head2 A note on history

Before XML::LibXML 1.70, this class was available as a separate CPAN
distribution, intended to provide functionality shared between XML::LibXML,
XML::GDOME, and possibly other modules. Since there seems to be no progress in
this direction, we decided to merge XML::LibXML::Common 0.13 and XML::LibXML
1.70 to one CPAN distribution. 

The merge also naturally eliminates a practical and urgent problem experienced
by many XML::LibXML users on certain platforms, namely misterious misbehavior
of XML::LibXML occurring if the installed (often pre-packaged) version of
XML::LibXML::Common was compiled against an older version of libxml2 than
XML::LibXML. 

=head1 AUTHORS

Matt Sergeant, 
Christian Glahn, 
Petr Pajas


=head1 VERSION

1.70

=head1 COPYRIGHT

2001-2007, AxKit.com Ltd.

2002-2006, Christian Glahn.

2006-2009, Petr Pajas.

=cut
