re-opening a closed stdin?

[Bernard James POPE]

> You can call 'System.Posix.IO.dup stdin' and save this value.
> However, I think you then need to explicitely read from this fd as
> it is not possible to reset what GHC thinks stdin is currently to
> this new fd (I'll dig into this and maybe we'll get a
>    setStdin :: Fd -> IO ()
> from this, IIRC somebody else was asking for this, too).

How does this interact with Simon's proposal for hDuplicate?

Thanks for your help,
Bernie.