KNOTE(9) BSD Kernel Manual KNOTE(9)NAME
knote, KNOTE - raise kernel event
SYNOPSIS
#include <sys/param.h>
#include <sys/event.h>
void
knote(struct klist *list, long hint);
KNOTE(struct klist *list, long hint);
DESCRIPTION
The knote() function provides a hook into the kqueue kernel event notifi-
cation 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 ac-
tive 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 inter-
rupt priority level higher than splsched().
KNOTE() is a macro that calls knote(list, hint) if list is not empty.
SEE ALSOkqueue(2)HISTORY
The knote() and KNOTE() functions first appeared in FreeBSD 4.1, and then
in OpenBSD 2.9.
AUTHORS
The kqueue() system was written by Jonathan Lemon <jlemon@FreeBSD.org>.
MirOS BSD #10-current February 23, 2003 1
