Re: POLLRDHUP inconsistency between poll() and epoll

[Davide Libenzi <davidel@xmailserver.org>]

On Tue, 4 Apr 2006, Michael Kerrisk wrote:

> Davide,
>
> While playing about with the new POLLRDHUP flag, I've noticed
> an inconsistency, which may or may not be intentional...
>
> When a POLLRDHUP condition occurs, epoll_wait() tells us about
> the condition, regardless of whether or not we specified
> (E)POLLRDHUPP in the 'events' flag given to epoll_ctl()
> EPOLL_CTL_ADD.  In this respect, POLLRDHUP is treated just like
> POLLHUP and POLLERR.  This seems perfectly reasonable.
>
> By contrast, poll() will only tell us that POLLRDHUP occurred
> if we specified POLLRDHUP in the file descriptor 'events' mask
> given to the poll() call.  In other words, poll() treats
> POLLRDHUP differently from POLLHUP and POLLERR.  This seems
> a little strange.
>
> Is this difference really intended?  If it is, what is the
> reason for the difference?

No. It is definitely better to keep behaviour consistent with poll/select. 
I'll submit a patch ASAP. Thank you spotting this out!



- Davide


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