validating XML parser library for C++

 Xerces-C++ is a validating XML parser written in a portable subset of
 C++. Xerces-C++ makes it easy to give your application the ability
 to read and write XML data. A shared library is provided for parsing,
 generating, manipulating, and validating XML documents. Xerces-C++ is
 faithful to the XML 1.0 recommendation and associated standards (DOM
 1.0, DOM 2.0, SAX 1.0, SAX 2.0, Namespaces, XML Schema Part 1 and
 Part 2). It also provides experimental implementations of XML 1.1
 and DOM Level 3.0. The parser provides high performance, modularity,
 and scalability.