# phpman > perldoc > XML::LibXML::Common

## NAME
    [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown) - Constants and Character Encoding Routines

## SYNOPSIS
      use [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown);

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

## DESCRIPTION
    [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown) defines constants for all node types and provides interface to libxml2
    charset conversion functions.

    Since [XML::LibXML](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML/markdown) use their own node type definitions, one may want to use [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown)
    in its compatibility mode:

### Exporter TAGS
      use [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown) qw(:libxml);

    ":libxml" tag will use the [XML::LibXML](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML/markdown) Compatibility mode, which defines the old 'XML_'
    node-type definitions.

      use [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown) qw(:gdome);

    ":gdome" tag will use the [XML::GDOME](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGDOME/markdown) Compatibility mode, which defines the old 'GDOME_'
    node-type definitions.

      use [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown) qw(:w3c);

    This uses the nodetype definition names as specified for DOM.

      use [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown) qw(:encoding);

    This tag can be used to export only the charset encoding functions of [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown).

### Exports
    By default the W3 definitions as defined in the DOM specifications and the encoding functions
    are exported by [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown).

### Encoding functions
    To encode or decode a string to or from UTF-8, [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown) exports two functions, which
    provide an interface to the encoding support in "libxml2". Which encodings are supported by
    these functions depends on how "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
    functions via the "Encode" module, it is probably a good idea to use those instead.

    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.

    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.

    Both these functions report their errors on the standard error. If an error occurs 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.

  A note on history
    Before [XML::LibXML](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML/markdown) 1.70, this class was available as a separate CPAN distribution, intended to
    provide functionality shared between [XML::LibXML](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML/markdown), [XML::GDOME](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGDOME/markdown), and possibly other modules. Since
    there seems to be no progress in this direction, we decided to merge [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown) 0.13
    and [XML::LibXML](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML/markdown) 1.70 to one CPAN distribution.

    The merge also naturally eliminates a practical and urgent problem experienced by many
    [XML::LibXML](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML/markdown) users on certain platforms, namely mysterious misbehavior of [XML::LibXML](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML/markdown) occurring
    if the installed (often pre-packaged) version of [XML::LibXML::Common](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML%3A%3ACommon/markdown) was compiled against an
    older version of libxml2 than [XML::LibXML](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3ALibXML/markdown).

## AUTHORS
    Matt Sergeant, Christian Glahn, Petr Pajas

## VERSION
    2.0134

## COPYRIGHT
    2001-2007, AxKit.com Ltd.

    2002-2006, Christian Glahn.

    2006-2009, Petr Pajas.

## LICENSE
    This program is free software; you can redistribute it and/or modify it under the same terms as
    Perl itself.