Incorporating shareware restrictions in C++ software

Question

I wish to implement my software on a shareware basis, so that the user is given a maximum trial period of (say) 30 days with which to try out the software. On purchase I intend

Answer 1

If your software is really useful, you'll certainly find cracked copies on P2P before you see your first order. This will happen no matter how sophisticated is the license enforcement code you are going to implement.

That said, just store first-run date somewhere (may be registry, if on Windows) and after 30 days refuse to start, or just open a reminder window.

Don't worry about cheaters, they'll find a way around your restrictions no matter what. Worry about your honest customers and try hard not to make their life harder.

Eric Sink has written more about this here (section 4).