Is it safe to eat from a glazed piece of pottery?

I want to start making my own ceramics, as my art teacher has a kiln..I have been looking for clays and have found some that are FDA safe and stuff, but once you fire it and put the glaze on, does it just become a show-piece? Does the glaze make it unsafe to eat from, or can I glaze it and still be able to eat from it? Because if I start making pottery, I'd like to make functional pieces, maybe even dishes, bowls, and cups, not just things to sit on a shelf and look at...thanks again, and God bless