I recently made a small program, for a game called canvas rider (canvasrider.com), that makes ramps (probably not really important what it does). I want to register it under GNU GPL license. I know I will have to give away the source code, and I want to do that! But how exactly do I do this? Do I just copy & paste the license in the project? Or do I have to register it somewhere, for example on the fsf.org website. This is not that big of a program (under 2000 C++ lines of code), so if it is too much bother, I will just give away the code without licencing it. Also majority of my users are going to be Windows users, I had to make a Windows version, that uses windows functions like SetCursorPos() and others. Does it violate the GNU License or not?