the vast majority of revolvers have no safety
for semi-auto handguns, it is about 50-50, some models do, some models don't.
One of Glock's selling features is it is a very simple gun, very few external controls, so no safety swith on it. (there are internal safeties that keep it from firing if dropped, or even if whacked with a sledgehammer)
I don't know why Glock thought it was a good feature...oh wait, yes I do! There are some cops who are smart and honest and know about guns, but usually cops are deficient in at least one of those 3 catagores, sometimes more. So a gun that you simply "point and pull trigger" is good. What could go wrong with that? Humm, let's see what this DEA cop does http://www.youtube.com/watch?v=am-Qdx6vky0
Frequently, for a gun to have the safety on, it needs to first have the hammer ******.
A safety feature found in many guns is that it takes a big long hard trigger pull to fire the first round, or with some older guns like the cowboys used, you can pull on the trigger all day and the gun will never fire, you have to thumb-c.ock the hammer first for every shot.