Hm, C language (itself) hasn't got much major changes since ANSI standardization. I would say that one is able to grasp changes relevant to him, by whipping through the changelog for 10-15 minutes
Edit: If you are critizing K&R for not teaching how to write safest code then, well, you are right. It is simply not meant to do that
Edit: If you are critizing K&R for not teaching how to write safest code then, well, you are right. It is simply not meant to do that