pugixml 
pugixml is a C++ XML processing library, which consists of a DOM-like interface with rich traversal/modification capabilities, an extremely fast XML parser which constructs the DOM tree from an XML file/buffer, and an XPath 1.0 implementation for complex data-driven tree queries. Full Unicode support is also available, with Unicode interface variants and conversions between different Unicode encodings (which happen automatically during parsing/saving).
pugixml is used by a lot of projects, both open-source and proprietary, for performance and easy-to-use interface.
Documentation
Documentation for the current release of pugixml is available on-line as two separate documents:
- Quick-start guide, that aims to provide enough information to start using the library;
- Complete reference manual, that describes all features of the library in detail.
You’re advised to start with the quick-start guide; however, many important library features are either not described in it at all or only mentioned briefly; if you require more information you should read the complete manual.
License
This library is available to anybody free of charge, under the terms of MIT License (see LICENSE.md).