tail -f behaviour in ghc.

[Alex Ferguson]

I suspect this is more of a "my patchy knowledge about file handles"
question than a ghc or a Haskell question, but at the risk of revealing
same in public...

Is it possible to implement "follow mode" behaviour, a la tail -f,
without using "seek" (or hSetPosn, which I assume is essentially
seek slightly abstractified).  Essentially this comes down to whether
once a handle reaches "eof", whether than can be subsequently
falsified.

I suspect the intended and actual behaviour in all cases is "as per
Unix handles", but shouldn't it in principle be specified independently
thereof?

Cheers,
Alex.