4.2bsd eof flag in stdio

[Brandon Allbery]

The Plexus manuals have an entry for a command (I forget the name and
I'm 25 miles or so away from the manuals at the moment :-) that works
like cat except that EOF it sleeps for some user-specified amount of
time and then tries to read to the next EOF, so on forever.  This is
for ORDINARY FILES, mind you (i.e. redirected output from make; I'd like
to see that option); if an ordinary file can be so handled, why should
a terminal be any different?  Especially since the terminal works that
way anyway???  (About you DECcies:  I remember a problem on a DEC 20/60
that forced a shutdown because the program was looking for hardware EOF
on a terminal.  I don't expect to EVER see that on a Unix system.  If
that bug exists in TOPS-20, why not other nonsensical bugs -- and I choose
to treat sticky EOF as a bug, given that a terminal doesn't sticky EOF
at all, in reality.

I give you 3 choices:

1) inconsistent file handling.  What sticky EOF is in 4.2bsd, what it
is on any system that treats magtape EOFs as not absolute (most, I think)
EXCEPT standard Unix.  And if you do that to Unix, you lose the whole
argument for Unix because files are *no longer* always identical in the
view of the program.  In fact, I don't think the result can be CALLED
Unix.

2) consistent file handling with sticky EOF.  And how do you propose
to make compatible magtapes?

3) consistent file handling with NON-sticky EOF.  What most Unix versions
do.  Thus working nicely with magtapes and terminals; and also useful
in examining dynamic files like the running output of make (or
/usr/spool/uucp/LOGFILE :-)

--bsa
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