The design and performance of the BXML format and the CWXML library are characterized in
this report.
There's no external API documentation available yet, but the header files are quite well commented. You'll want to read "cw_xmlscan.h" and "cw_xmltree.h" in the distribution for the parser and "cw_xmlgen.h" for the generator.
Some test programs are included with the distribution in the "cwxmlutil" directory so you can see some examples of using the API.