4.2BSD _filbuf() question

[gwyn%brl-vld at BRL-VLD.ARPA]

From:      Doug Gwyn (VLD/VMB) <gwyn%brl-vld at BRL-VLD.ARPA>

What would you expect to see when reading past the end of a file,
anyway?  I can imagine answers for keyboards and magtape but not
for files in general.  Until you do something to reposition the
stream, I see no reason for EOF status to be cleared.

In answer to the question of whether it is reasonable to change this
behavior, I would say that if it was not explicitly documented then
programmers have no right to expect it to be stable and should not
have relied upon it in the first place.  Remember sprintf() return
values?