Differential D26668 Diff 78167 lib/libc/sys/kqueue.2

Changeset View

Standalone View

lib/libc/sys/kqueue.2

	Show All 39 Lines
	.Ft int			.Ft int
	.Fn kevent "int kq" "const struct kevent changelist" "int nchanges" "struct kevent eventlist" "int nevents" "const struct timespec *timeout"			.Fn kevent "int kq" "const struct kevent changelist" "int nchanges" "struct kevent eventlist" "int nevents" "const struct timespec *timeout"
	.Fn EV_SET "kev" ident filter flags fflags data udata			.Fn EV_SET "kev" ident filter flags fflags data udata
	.Sh DESCRIPTION			.Sh DESCRIPTION
	The			The
	.Fn kqueue			.Fn kqueue
	system call			system call
	provides a generic method of notifying the user when an event			provides a generic method of notifying the user when an event
	happens or a condition holds, based on the results of small			happens or a condition holds, based on the results of small
				kibAuthorUnsubmitted Done Inline Actions This is unrelated but the diff is generated from the branch that has split patch, so it is separate change in git. kib: This is unrelated but the diff is generated from the branch that has split patch, so it is…
	pieces of kernel code termed filters.			pieces of kernel code termed filters.
	A kevent is identified by the (ident, filter) pair; there may only			A kevent is identified by the (ident, filter) pair; there may only
	be one unique kevent per kqueue.			be one unique kevent per kqueue.
	.Pp			.Pp
	The filter is executed upon the initial registration of a kevent			The filter is executed upon the initial registration of a kevent
	in order to detect whether a preexisting condition is present, and is also			in order to detect whether a preexisting condition is present, and is also
	executed whenever an event is passed to the filter for evaluation.			executed whenever an event is passed to the filter for evaluation.
	If the filter determines that the condition should be reported,			If the filter determines that the condition should be reported,
	▲ Show 20 Lines • Show All 272 Lines • ▼ Show 20 Lines
	returning.			returning.
	.It "BPF devices"			.It "BPF devices"
	Returns when the BPF buffer is full, the BPF timeout has expired, or			Returns when the BPF buffer is full, the BPF timeout has expired, or
	when the BPF has			when the BPF has
	.Dq immediate mode			.Dq immediate mode
	enabled and there is any data to read;			enabled and there is any data to read;
	.Va data			.Va data
	contains the number of bytes available.			contains the number of bytes available.
				.It Eventfds
				Returns when the counter is greater than 0;
				.Va data
				contains the counter value, which must be cast to
				.Vt uint64_t .
	.El			.El
	.It Dv EVFILT_WRITE			.It Dv EVFILT_WRITE
	Takes a descriptor as the identifier, and returns whenever			Takes a descriptor as the identifier, and returns whenever
	it is possible to write to the descriptor.			it is possible to write to the descriptor.
	For sockets, pipes			For sockets, pipes
	and fifos,			and fifos,
	.Va data			.Va data
	will contain the amount of space remaining in the write buffer.			will contain the amount of space remaining in the write buffer.
	The filter will set			The filter will set
	.Dv EV_EOF			.Dv EV_EOF
	when the reader disconnects, and for the fifo case, this will be cleared			when the reader disconnects, and for the fifo case, this will be cleared
	when a new reader connects.			when a new reader connects.
	Note that this filter is not supported for vnodes or BPF devices.			Note that this filter is not supported for vnodes or BPF devices.
	.Pp			.Pp
	For sockets, the low water mark and socket error handling is			For sockets, the low water mark and socket error handling is
	identical to the			identical to the
	.Dv EVFILT_READ			.Dv EVFILT_READ
	case.			case.
				.Pp
				For eventfds,
				.Va data
				will contain the maximum value that can be added to the counter
				without blocking.
	.It Dv EVFILT_EMPTY			.It Dv EVFILT_EMPTY
	Takes a descriptor as the identifier, and returns whenever			Takes a descriptor as the identifier, and returns whenever
	there is no remaining data in the write buffer.			there is no remaining data in the write buffer.
	.It Dv EVFILT_AIO			.It Dv EVFILT_AIO
	Events for this filter are not registered with			Events for this filter are not registered with
	.Fn kevent			.Fn kevent
	directly but are registered via the			directly but are registered via the
	.Va aio_sigevent			.Va aio_sigevent
	▲ Show 20 Lines • Show All 448 Lines • Show Last 20 Lines