Ha!  You fell into my trap!  getc() returns an int!  (I don't know if EOF is _always_ "all bits set", and even if it is, that's only -1 on a twos-complement machine, if we want to head off into some real pedantry...)

The need to use feof() and ferror() at least appear in the BUGS section on my Mac.  Linux is not so gracious.  The real bug, if you ask me, which no one did, is that getc() and pals return an int rather than a char, which is surprising and certainly has tripped me up several times across the decades (and yes, I understand that since any character value is a legal character to have gotten, you need some other way of signalling an error).