I don't think there's a way of doing that using the APIs. The nearest you can get is to read an entire Section, but you still have to pass the section name. The alternative would be to read the .ini file as a flat file and parse the data accordingly. That would complicate the entire process.

Why do you not want to specify the Section? At some point in time your code is going to have to know what Section it's processing and the key / value pairs in it, so rather than 'discovering' it why not specify it.?