To me it is overkill to bring into two complex libraries like multi_index and serialize to handle a "simple" config file. By the way, is it even possible to have serialize work with textual files or does it always use a binary format? If so, the combination of multi_index and serialize is disqualified for a simple config file.
Serialization can handle various formats, and is explicitely designed to be extensible. One of the formats is XML. However, Serialization does not handle arbitrary (simple) XML, AFAIK.
1. Why do you care? What difference does it make what is the format of the permanent storage you are uging for your configuration. You are not going to edit this manualy anyway. 2. If you insist you could always implement your own format SimpleXML instead of reinventing the wheel. Gennadiy