pugixml is a light-weight C++ XML processing library. It features:

* DOM-like interface with rich traversal/modification capabilities
* Extremely fast non-validating XML parser which constructs the DOM tree from an
  XML file/buffer
* XPath 1.0 implementation for complex data-driven tree queries
* Full Unicode support with Unicode interface variants and automatic encoding
  conversions

WWW: https://pugixml.org/