On Thu, 9 Oct 2003, Dan Kegel wrote:
> Davide Libenzi wrote:
> > Hi Dan. The POLLHUP is a condition that does not preclude the socket to
> > have data to be still read. The correct approach, with both and new epoll,
> > is to register the event and read until data is available (if you need
> > to). Then, if a POLLHUP has been received, do not go to wait for POLLINs.
>
> Sounds like I need to go read Stevens again.
>
> For what it's worth, SuSv3 says in the poll() man page:
>
> POLLHUP
> The device has been disconnected. This event and POLLOUT are
> mutually-exclusive; a stream can never be writable if a hangup has
> occurred. However, this event and POLLIN, POLLRDNORM, POLLRDBAND,
> or POLLPRI are not mutually-exclusive.
>
> which doesn't quite say that POLLHUP may be signalled when
> there's still bunches of data to read, but it comes close.
If you think about it, it comes fairly simple. Suppose you have:
PEER PEER
send 10k
recv 2k
send FIN
POLLHUP
(8k pending here)
- Davide
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