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Drop trailing whitespace, and some mdoc fixes and improvements.

This commit is contained in:
wiz 2002-09-25 00:55:16 +00:00
parent 5dbdce59f0
commit 968f39c890
1 changed files with 46 additions and 42 deletions
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88
lib/libc/sys/kqueue.2
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@ -1,4 +1,4 @@
.\" $NetBSD: kqueue.2,v 1.5 2002/09/24 11:38:16 jdolecek Exp $ .\" $NetBSD: kqueue.2,v 1.6 2002/09/25 00:55:16 wiz Exp $
.\" .\"
.\" Copyright (c) 2000 Jonathan Lemon .\" Copyright (c) 2000 Jonathan Lemon
.\" All rights reserved. .\" All rights reserved.
@ -42,9 +42,9 @@
.Sh LIBRARY .Sh LIBRARY
.Lb libc .Lb libc
.Sh SYNOPSIS .Sh SYNOPSIS
.Fd #include <sys/types.h> .Fd #include \*[Lt]sys/types.h\*[Gt]
.Fd #include <sys/event.h> .Fd #include \*[Lt]sys/event.h\*[Gt]
.Fd #include <sys/time.h> .Fd #include \*[Lt]sys/time.h\*[Gt]
.Ft int .Ft int
.Fn kqueue "void" .Fn kqueue "void"
.Ft int .Ft int
@ -68,7 +68,7 @@ The filter is also run when the user attempts to retrieve the kevent
from the kqueue. from the kqueue.
If the filter indicates that the condition that triggered If the filter indicates that the condition that triggered
the event no longer holds, the kevent is removed from the kqueue and the event no longer holds, the kevent is removed from the kqueue and
is not returned. is not returned.
.Pp .Pp
Multiple events which trigger the filter do not result in multiple Multiple events which trigger the filter do not result in multiple
kevents being placed on the kqueue; instead, the filter will aggregate kevents being placed on the kqueue; instead, the filter will aggregate
@ -95,34 +95,40 @@ is used to register events with the queue, and return any pending
events to the user. events to the user.
.Fa changelist .Fa changelist
is a pointer to an array of is a pointer to an array of
.Va kevent .Va kevent
structures, as defined in structures, as defined in
.Aq Pa sys/event.h . .Aq Pa sys/event.h .
All changes contained in the All changes contained in the
.Fa changelist .Fa changelist
are applied before any pending events are read from the queue. are applied before any pending events are read from the queue.
.Fa nchanges .Fa nchanges
gives the size of gives the size of
.Fa changelist . .Fa changelist .
.Fa eventlist .Fa eventlist
is a pointer to an array of kevent structures. is a pointer to an array of kevent structures.
.Fa nevents .Fa nevents
determines the size of determines the size of
.Fa eventlist . .Fa eventlist .
If If
.Fa timeout .Fa timeout
is a non-NULL pointer, it specifies a maximum interval to wait is a
.No non- Ns Dv NULL
pointer, it specifies a maximum interval to wait
for an event, which will be interpreted as a struct timespec. If for an event, which will be interpreted as a struct timespec. If
.Fa timeout .Fa timeout
is a NULL pointer, is a
.Dv NULL
pointer,
.Fn kevent .Fn kevent
waits indefinitely. To effect a poll, the waits indefinitely. To effect a poll, the
.Fa timeout .Fa timeout
argument should be non-NULL, pointing to a zero-valued argument should be
.No non- Ns Dv NULL ,
pointing to a zero-valued
.Va timespec .Va timespec
structure. The same array may be used for the structure. The same array may be used for the
.Fa changelist .Fa changelist
and and
.Fa eventlist . .Fa eventlist .
.Pp .Pp
.Fn EV_SET .Fn EV_SET
@ -160,7 +166,7 @@ Actions to perform on the event.
.It fflags .It fflags
Filter-specific flags. Filter-specific flags.
.It data .It data
Filter-specific data value. Filter-specific data value.
.It udata .It udata
Opaque user-defined value passed through the kernel unchanged. Opaque user-defined value passed through the kernel unchanged.
.El .El
@ -183,8 +189,8 @@ Disable the event so
.Fn kevent .Fn kevent
will not return it. The filter itself is not disabled. will not return it. The filter itself is not disabled.
.It EV_DELETE .It EV_DELETE
Removes the event from the kqueue. Events which are attached to Removes the event from the kqueue. Events which are attached to
file descriptors are automatically deleted on the last close of file descriptors are automatically deleted on the last close of
the descriptor. the descriptor.
.It EV_ONESHOT .It EV_ONESHOT
Causes the event to return only the first occurrence of the filter Causes the event to return only the first occurrence of the filter
@ -202,19 +208,17 @@ See
.Sx RETURN VALUES .Sx RETURN VALUES
below. below.
.El .El
.Pp
.Ss Filters .Ss Filters
.Pp
Filters are identified by a number. Filters are identified by a number.
There are two types of filters; pre-defined filters which There are two types of filters; pre-defined filters which
are described below, and third-party filters that may be added with are described below, and third-party filters that may be added with
.Xr kfilter_register 2 .Xr kfilter_register 2
by kernel sub-systems, third-party device drivers, or loadable by kernel sub-systems, third-party device drivers, or loadable
kernel modules. kernel modules.
.Pp .Pp
As a third-party filter is referenced by a well-known name instead As a third-party filter is referenced by a well-known name instead
of a statically assigned number, two of a statically assigned number, two
.Xr ioctl 2 s .Xr ioctl 2 Ns s
are supported on the file descriptor returned by are supported on the file descriptor returned by
.Fn kqueue .Fn kqueue
to map a filter name to a filter number, and vice-versa (passing to map a filter name to a filter number, and vice-versa (passing
@ -246,7 +250,7 @@ struct kfilter_mapping {
}; };
.Ed .Ed
.Pp .Pp
Arguments may be passed to and from the filter via the Arguments may be passed to and from the filter via the
.Va fflags .Va fflags
and and
.Va data .Va data
@ -275,9 +279,9 @@ subject to the
.Dv SO_RCVLOWAT .Dv SO_RCVLOWAT
value of the socket buffer. value of the socket buffer.
This may be overridden with a per-filter low water mark at the This may be overridden with a per-filter low water mark at the
time the filter is added by setting the time the filter is added by setting the
NOTE_LOWAT NOTE_LOWAT
flag in flag in
.Va fflags , .Va fflags ,
and specifying the new low water mark in and specifying the new low water mark in
.Va data . .Va data .
@ -288,7 +292,7 @@ contains the number of bytes in the socket buffer.
If the read direction of the socket has shutdown, then the filter If the read direction of the socket has shutdown, then the filter
also sets EV_EOF in also sets EV_EOF in
.Va flags , .Va flags ,
and returns the socket error (if any) in and returns the socket error (if any) in
.Va fflags . .Va fflags .
It is possible for EOF to be returned (indicating the connection is gone) It is possible for EOF to be returned (indicating the connection is gone)
while there is still data pending in the socket buffer. while there is still data pending in the socket buffer.
@ -311,25 +315,25 @@ returning.
.It EVFILT_WRITE .It 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. For sockets, pipes, it is possible to write to the descriptor. For sockets, pipes,
fifos and ttys, fifos, and ttys,
.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 EV_EOF when the reader disconnects, and for The filter will set EV_EOF when the reader disconnects, and for
the fifo case, this may be cleared by use of EV_CLEAR. the fifo case, this may be cleared by use of EV_CLEAR.
Note that this filter is not supported for vnodes. Note that this filter is not supported for vnodes.
.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 EVFILT_READ case. identical to the EVFILT_READ case.
.It EVFILT_AIO .It EVFILT_AIO
This is not implemented in This is not implemented in
.Nx . .Nx .
.ig .ig
The sigevent portion of the AIO request is filled in, with The sigevent portion of the AIO request is filled in, with
.Va sigev_notify_kqueue .Va sigev_notify_kqueue
containing the descriptor of the kqueue that the event should containing the descriptor of the kqueue that the event should
be attached to, be attached to,
.Va sigev_value .Va sigev_value
containing the udata value, and containing the udata value, and
.Va sigev_notify .Va sigev_notify
set to SIGEV_EVENT. set to SIGEV_EVENT.
When the aio_* function is called, the event will be registered When the aio_* function is called, the event will be registered
@ -340,7 +344,7 @@ argument set to the
returned by the aio_* function. returned by the aio_* function.
The filter returns under the same conditions as aio_error. The filter returns under the same conditions as aio_error.
.Pp .Pp
Alternatively, a kevent structure may be initialized, with Alternatively, a kevent structure may be initialized, with
.Va ident .Va ident
containing the descriptor of the kqueue, and the containing the descriptor of the kqueue, and the
address of the kevent structure placed in the address of the kevent structure placed in the
@ -349,7 +353,7 @@ field of the AIO request. However, this approach will not work on
architectures with 64-bit pointers, and should be considered depreciated. architectures with 64-bit pointers, and should be considered depreciated.
.. ..
.It EVFILT_VNODE .It EVFILT_VNODE
Takes a file descriptor as the identifier and the events to watch for in Takes a file descriptor as the identifier and the events to watch for in
.Va fflags , .Va fflags ,
and returns when one or more of the requested events occurs on the descriptor. and returns when one or more of the requested events occurs on the descriptor.
The events to monitor are: The events to monitor are:
@ -368,7 +372,7 @@ The link count on the file changed.
.It NOTE_RENAME .It NOTE_RENAME
The file referenced by the descriptor was renamed. The file referenced by the descriptor was renamed.
.It NOTE_REVOKE .It NOTE_REVOKE
Access to the file was revoked via Access to the file was revoked via
.Xr revoke 2 .Xr revoke 2
or the underlying fileystem was unmounted. or the underlying fileystem was unmounted.
.El .El
@ -377,7 +381,7 @@ On return,
.Va fflags .Va fflags
contains the events which triggered the filter. contains the events which triggered the filter.
.It EVFILT_PROC .It EVFILT_PROC
Takes the process ID to monitor as the identifier and the events to watch for Takes the process ID to monitor as the identifier and the events to watch for
in in
.Va fflags , .Va fflags ,
and returns when the process performs one or more of the requested events. and returns when the process performs one or more of the requested events.
@ -390,7 +394,7 @@ The process has exited.
The process has called The process has called
.Fn fork . .Fn fork .
.It NOTE_EXEC .It NOTE_EXEC
The process has executed a new process via The process has executed a new process via
.Xr execve 2 .Xr execve 2
or similar call. or similar call.
.It NOTE_TRACK .It NOTE_TRACK
@ -400,7 +404,7 @@ calls. The parent process will return with NOTE_TRACK set in the
.Va fflags .Va fflags
field, while the child process will return with NOTE_CHILD set in field, while the child process will return with NOTE_CHILD set in
.Va fflags .Va fflags
and the parent PID in and the parent PID in
.Va data . .Va data .
.It NOTE_TRACKERR .It NOTE_TRACKERR
This flag is returned if the system was unable to attach an event to This flag is returned if the system was unable to attach an event to
@ -415,7 +419,7 @@ Takes the signal number to monitor as the identifier and returns
when the given signal is delivered to the current process. when the given signal is delivered to the current process.
This coexists with the This coexists with the
.Fn signal .Fn signal
and and
.Fn sigaction .Fn sigaction
facilities, and has a lower precedence. The filter will record facilities, and has a lower precedence. The filter will record
all attempts to deliver a signal to a process, even if the signal has all attempts to deliver a signal to a process, even if the signal has
@ -429,7 +433,7 @@ This filter automatically sets the EV_CLEAR flag internally.
.Sh RETURN VALUES .Sh RETURN VALUES
.Fn kqueue .Fn kqueue
creates a new kernel event queue and returns a file descriptor. creates a new kernel event queue and returns a file descriptor.
If there was an error creating the kernel event queue, a value of -1 is If there was an error creating the kernel event queue, a value of \-1 is
returned and errno set. returned and errno set.
.Pp .Pp
.Fn kevent .Fn kevent
@ -450,7 +454,7 @@ set in
and the system error in and the system error in
.Va data . .Va data .
Otherwise, Otherwise,
.Dv -1 .Dv \-1
will be returned, and will be returned, and
.Dv errno .Dv errno
will be set to indicate the error condition. will be set to indicate the error condition.
@ -477,9 +481,9 @@ function fails if:
.It Bq Er EACCES .It Bq Er EACCES
The process does not have permission to register a filter. The process does not have permission to register a filter.
.It Bq Er EFAULT .It Bq Er EFAULT
There was an error reading or writing the There was an error reading or writing the
.Va kevent .Va kevent
structure. structure.
.It Bq Er EBADF .It Bq Er EBADF
The specified descriptor is invalid. The specified descriptor is invalid.
.It Bq Er EINTR .It Bq Er EINTR
@ -505,8 +509,8 @@ The specified process to attach to does not exist.
.Xr sigaction 2 , .Xr sigaction 2 ,
.Xr write 2 , .Xr write 2 ,
.Xr signal 3 , .Xr signal 3 ,
.Xr kfilter_register 9 . .Xr kfilter_register 9 ,
.Xr knote 9 . .Xr knote 9
.Sh HISTORY .Sh HISTORY
The The
.Fn kqueue .Fn kqueue
@ -529,7 +533,7 @@ system and this manual page were written by
port and manpage additions were done by port and manpage additions were done by
.An Luke Mewburn Aq lukem@NetBSD.org , .An Luke Mewburn Aq lukem@NetBSD.org ,
.An Jason Thorpe Aq thorpej@NetBSD.org , .An Jason Thorpe Aq thorpej@NetBSD.org ,
and and
.An Jaromir Dolecek Aq jdolecek@NetBSD.org . .An Jaromir Dolecek Aq jdolecek@NetBSD.org .
.Sh BUGS .Sh BUGS
It is currently not possible to watch a It is currently not possible to watch a