How do you know if HE is gay?

I met this guy some time ago... We have some interests in common but we haven't talked that much. The other day, after a lengthy conversation about a show we both enjoy, we discovered a shared passion for terrible movies, so he invited me to his cinema club (we're both in the same college) to watch a terrible movie we both love. I sometimes struggle to speak face to face, specially if there are other people involved, which was the case, and I can't quite figure out if this guy is gay or not... I like him quite a bit, for how little i know him, and I'd love to be his friend, gay or not, but I also find him incredibly cute, and would like to know if i can expect something else from him.We still haven't got personal with each other, although I enjoy talking to him. How could I know this?