Re: [take25 1/6] kevent: Description.

Ulrich Drepper
2006-11-22T23:55:54Z

Evgeniy Polyakov wrote:
> + struct kevent_ring
> + {
> + unsigned int ring_kidx, ring_uidx, ring_over;
> + struct ukevent event[0];
> + }
> + [...]
> +ring_uidx - index of the first entry userspace can start reading from

Do we need this value in the structure? Userlevel cannot and should not
be able to modify it. So, userland has in any case to track the tail
pointer itself. Why then have this value at all?

After kevent_init() the tail pointer is implicitly assumed to be 0.
Since the front pointer (well index) is also zero nothing is available
for reading.

--
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖