Is close/fclose on stdin guaranteed to be correct?

Question

It seems as though the following calls do what you\'d expect (close the stream and not allow any further input - anything waiting for input on the stream returns error), but

Answer 1

DO NOT DO a close on fileno(FILE*). FILE is a buffering object. Looking into its implementation and meddling with its state carries all the caveats and dangers that would come with similar misbehavior on any other software module.

Don't do it.

AGH. Seriously. Nasty.