I'm thinking of learning C (or C++, or Java). I don't like OO, I want to do text processing, I like security, and I'd like to develop stuff on my Windows computer that I could then use on my web host's Apache server, and I want a language more marketable than Python, Haskell, etc. I know I'm not going to get everything.
Anyway, the thing I'm thinking of now is how portable C is from one Windows OS to another and from one Linux distro to another. Is that an issue at all, or is the only portability issue between Windows and Linux?