I found RapidXml works well. However, if there is a syntax error in the XML file, it doesn't give you much indication as to what the problem is.
There is often confusion about sitemaps, how they are implemented, and how they can be best leveraged with search engine tools for search engine optimization (SEO).
Do you know about the --ignore-matching-lines option to GNU diff? I recently found a great use for it on a recent project here at Atomic.
In XML, CDATA sections allow XML markup to be embedded, but not interpreted as part of the XML document itself.