void
knote(
struct klist *list
, long hint
)
KNOTE(
struct klist *list
, long hint
)
)
function provides a hook into the kqueue kernel event notification
mechanism to allow sections of the kernel to raise a kernel event
in the form of a
`knote',
which is a
struct
knote
as defined in
<
sys/event.h
>.
knote()
takes a singly linked
list
of knotes, along with a
hint
(which is passed to the appropriate filter routine).
knote()
then walks the
list
making calls to the filter routine for each knote.
As each knote contains a reference to the data structure that it is
attached to, the filter may choose to examine the data structure in
deciding whether an event should be reported.
The
hint
is used to pass in additional information, which may not be present in
the data structure that the filter examines.
If the filter decides that the event should be returned, it returns a
non-zero value and
knote()
links the knote onto the tail end of the active list in the
corresponding kqueue for the application to retrieve.
If the knote is already on the active list, no action is taken, but the
call to the filter occurs in order to provide an opportunity for the
filter to record the activity.
knote()
must not be called from interrupt contexts running at an interrupt
priority level higher than
splsched(
).
KNOTE()
is a macro that calls
knote(
list
, hint
)
if
list
is not empty.
)
and
KNOTE(
)
functions first appeared in
FreeBSD4.1,
and then in
NetBSD2.0.
)
system was written by
Jonathan Lemon <jlemon@FreeBSD.org>