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Re: [Xen-devel] [PATCH V4] Switch from select() to poll() in xenconsoled's IO loop

Ian Campbell writes ("Re: [Xen-devel] [PATCH V4] Switch from select() to poll() 
in xenconsoled's IO loop"):
> On Mon, 2013-01-07 at 14:28 +0000, Wei Liu wrote
> > -                       if (d->master_fd != -1 && FD_ISSET(d->master_fd,
> > -                                                          &readfds))
> This is probably one for Ian J but I wonder if you need to handle
> POLLERR or POLLHUP here. ISTR some of oddness WRT these when Ian
> implemented the libxl event subsystem.

I haven't read the patch in question but:

You certainly need to check for POLLERR and POLLHUP.  They appear in
revents even if not requested.  Normally they can be treated as fatal
for the descriptor.

You should also think about POLLPRI.  Often it's correct to request it
and then treat it as fatal for the descriptor if it occurs.

(I haven't read the patch I'm afraid...)

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