Nope. fgets reads at most size-1 characters or until encountering a newline. If there's enough room, the newline gets put in the buffer, otherwise it doesn't. Anyway I hoped this would demonstrate that you could always just check the first character of the buffer for your quit ...signal... thingy.[/technical word]
Of course if somebody entered
tom
quincy
harry
The loop would quit too soon, so I would just keep reading until a blank line is entered (a buffer containing \n as the first character).