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KNOTE(9)                   Kernel Developer's Manual                  KNOTE(9)

NAME
     knote, KNOTE - raise kernel event

SYNOPSIS
     #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
     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(9).

     KNOTE() is a macro that calls knote(list, hint) if list is not empty.

SEE ALSO
     kqueue(2), kfilter_register(9)

HISTORY
     The knote() and KNOTE() functions first appeared in FreeBSD 4.1, and then
     in NetBSD 2.0.

AUTHORS
     The kqueue(2) system was written by Jonathan Lemon <jlemon@FreeBSD.org>.

NetBSD 10.99                   February 18, 2004                  NetBSD 10.99