I generally think that GNU GPL is best used for applications, mainly because users of applications will generally find it much harder to replace your applicatio

I generally think that GNU GPL is best used for applications, mainly because users of applications will generally find it much harder to replace your applications with alternatives, which is usually not the case for libraries. This is not the hard-and-fast rule though; there are some classes of applications which can be replaced easily, like compilers and command-line utilities with easy migration paths. Pretty much every library is designed for developers and inherently replacable if its license doesn't fit well, so its license has to be also developer-friendly if you want it to be used by many developers. (In fact, I even don't use permissive licenses for libraries nowadays, the public domain dedication works for me.) Of course whether you actually want that or not is up to you. > I designed libpgn to have small seperate 'modules' each serving functions (pgn_metadata_*, pgn_moves_*, etc) to parse a small portion of the file, that way the root pgn.h just calls and builds the block with all the small parsers. C doesn't really have any module system and any such notion has to be entirely logical. It should be easy to keep the current structure but amalgamate all files into a single physical file.