See http://rapidxml.sourceforge.net/ for more information and complete documentation.

RapidXml is an attempt to create the fastest XML parser possible, while retaining useability, 
portability and reasonable W3C compatibility. It is an in-situ parser written in modern C++, 
with parsing speed approaching that of strlen function executed on the same data.

The license agreement for logog is viewable at http://rapidxml.sourceforge.net/license.txt