This used to be more common, especially in the video game industry. Pay for a piece of software like a physics engine or GUI library, get full C++ source code.

This used to be more common, especially in the video game industry. Pay for a piece of software like a physics engine or GUI library, get full C++ source code. Usually those companies had legal departments to chase down non-paying infringers though... Sidenote: If you call it "open source" you'll definitely get a lot of hate from a vocal cadre who want "open source" to only apply to copyleft/BSD/MIT/etc. licenses. (I assume you're not using one of those licenses, because otherwise someone could just host your code as a free download).