> >
> > I have a test driver that returns these values from the poll() function.
> > However, the application
> > that called the select() is not getting an error. Instead, the select
> > is returning that the particular file descriptor is, in this case,
> > 'readable' !
>
> Take a look at "selscan" algorithm in /usr/src/sys/kern/sys_generic.c
> if you wish to learn more.
>
> Basically, if your driver doesn't implement the poll() functionality,
> it can always return 0. This will ensure that select never wakes up
> because of a file descriptor associated with your driver.
>
thanks for your reply. I realise that one can return 0.
My point is that if the driver returns POLLERR or POLLHUP,
it is not getting handled correctly in sys_generic.c...
It seems to me that a positive (non-zero) return value is being
interpreted as 'readiness', although there is a comment in
sys_generic.c that the backend (driver) can also return POLLHUP or
POLLERR.
--Vasudha
To Unsubscribe: send mail to majord...@freebsd.org
with "unsubscribe freebsd-hackers" in the body of the message
