Make it public domain. While any major corporation could still use it without you being paid, many don't and will request you provide the same code but under a

Make it public domain. While any major corporation could still use it without you being paid, many don't and will request you provide the same code but under a license their lawyers are comfortable with. SQLite sort of runs on this model -- it's public domain, but the author has been asked by many big corps for licenses and pay for them. They also pay for direct support, mods to the code. The testing harnesses and other aspects of the development and testing of SQLite but which are not part of SQLite can be kept entirely proprietary. I don't know if this model would fit for your library, SQLite may have a very different niche as an embedded database, and frankly it is used everywhere, so not sure if that would work in your case, but it's another option to think about.