2004-11-03 13:51:07 +00:00
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.\" Copyright (c) 1993
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2015-02-07 06:39:47 +00:00
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.\" The Regents of the University of California. All rights reserved.
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2004-11-03 13:51:07 +00:00
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.\"
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2015-02-07 07:26:27 +00:00
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.\" %%%LICENSE_START(BSD_3_CLAUSE_UCB)
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2004-11-03 13:51:07 +00:00
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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2015-02-07 06:39:47 +00:00
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.\" 3. Neither the name of the University nor the names of its contributors
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2004-11-03 13:51:07 +00:00
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\" %%%LICENSE_END
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2004-11-03 13:51:07 +00:00
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.\"
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2015-02-07 06:39:47 +00:00
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.\" @(#)queue.3 8.2 (Berkeley) 1/24/94
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.\" $FreeBSD$
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2004-11-03 13:51:07 +00:00
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.\"
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2015-02-07 07:14:26 +00:00
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.Dd February 7, 2015
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2015-02-07 06:39:47 +00:00
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.Dt QUEUE 3
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.Os
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.Sh NAME
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.Nm TAILQ_CONCAT ,
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.Nm TAILQ_EMPTY ,
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.Nm TAILQ_ENTRY ,
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.Nm TAILQ_FIRST ,
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.Nm TAILQ_FOREACH ,
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2015-02-07 07:05:23 +00:00
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.\" .Nm TAILQ_FOREACH_FROM ,
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.\" .Nm TAILQ_FOREACH_FROM_SAFE ,
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2015-02-07 06:39:47 +00:00
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.Nm TAILQ_FOREACH_REVERSE ,
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2015-02-07 07:05:23 +00:00
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.\" .Nm TAILQ_FOREACH_REVERSE_FROM ,
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.\" .Nm TAILQ_FOREACH_REVERSE_FROM_SAFE ,
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2020-10-23 14:38:26 +00:00
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.\" .Nm TAILQ_FOREACH_REVERSE_SAFE ,
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.\" .Nm TAILQ_FOREACH_SAFE ,
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2015-02-07 06:39:47 +00:00
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.Nm TAILQ_HEAD ,
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.Nm TAILQ_HEAD_INITIALIZER ,
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.Nm TAILQ_INIT ,
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.Nm TAILQ_INSERT_AFTER ,
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.Nm TAILQ_INSERT_BEFORE ,
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.Nm TAILQ_INSERT_HEAD ,
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.Nm TAILQ_INSERT_TAIL ,
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.Nm TAILQ_LAST ,
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.Nm TAILQ_NEXT ,
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.Nm TAILQ_PREV ,
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2020-10-23 14:57:32 +00:00
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.Nm TAILQ_REMOVE
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.\" .Nm TAILQ_SWAP
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2015-02-07 06:39:47 +00:00
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.Nd implementations of singly-linked lists, singly-linked tail queues,
|
2020-08-24 06:50:23 +00:00
|
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lists, tail queues, and circular queues
|
2015-02-07 06:39:47 +00:00
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.Sh SYNOPSIS
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.In sys/queue.h
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2004-11-03 13:51:07 +00:00
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.\"
|
2015-02-07 06:39:47 +00:00
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.Fn TAILQ_CONCAT "TAILQ_HEAD *head1" "TAILQ_HEAD *head2" "TAILQ_ENTRY NAME"
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.Fn TAILQ_EMPTY "TAILQ_HEAD *head"
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.Fn TAILQ_ENTRY "TYPE"
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.Fn TAILQ_FIRST "TAILQ_HEAD *head"
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.Fn TAILQ_FOREACH "TYPE *var" "TAILQ_HEAD *head" "TAILQ_ENTRY NAME"
|
2015-02-07 07:05:23 +00:00
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.\" .Fn TAILQ_FOREACH_FROM "TYPE *var" "TAILQ_HEAD *head" "TAILQ_ENTRY NAME"
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.\" .Fn TAILQ_FOREACH_FROM_SAFE "TYPE *var" "TAILQ_HEAD *head" "TAILQ_ENTRY NAME" "TYPE *temp_var"
|
2015-02-07 06:39:47 +00:00
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.Fn TAILQ_FOREACH_REVERSE "TYPE *var" "TAILQ_HEAD *head" "HEADNAME" "TAILQ_ENTRY NAME"
|
2015-02-07 07:05:23 +00:00
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.\" .Fn TAILQ_FOREACH_REVERSE_FROM "TYPE *var" "TAILQ_HEAD *head" "HEADNAME" "TAILQ_ENTRY NAME"
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.\" .Fn TAILQ_FOREACH_REVERSE_FROM_SAFE "TYPE *var" "TAILQ_HEAD *head" "HEADNAME" "TAILQ_ENTRY NAME" "TYPE *temp_var"
|
2020-10-23 14:38:26 +00:00
|
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.\" .Fn TAILQ_FOREACH_REVERSE_SAFE "TYPE *var" "TAILQ_HEAD *head" "HEADNAME" "TAILQ_ENTRY NAME" "TYPE *temp_var"
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.\" .Fn TAILQ_FOREACH_SAFE "TYPE *var" "TAILQ_HEAD *head" "TAILQ_ENTRY NAME" "TYPE *temp_var"
|
2015-02-07 06:39:47 +00:00
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.Fn TAILQ_HEAD "HEADNAME" "TYPE"
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.Fn TAILQ_HEAD_INITIALIZER "TAILQ_HEAD head"
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.Fn TAILQ_INIT "TAILQ_HEAD *head"
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.Fn TAILQ_INSERT_AFTER "TAILQ_HEAD *head" "TYPE *listelm" "TYPE *elm" "TAILQ_ENTRY NAME"
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.Fn TAILQ_INSERT_BEFORE "TYPE *listelm" "TYPE *elm" "TAILQ_ENTRY NAME"
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.Fn TAILQ_INSERT_HEAD "TAILQ_HEAD *head" "TYPE *elm" "TAILQ_ENTRY NAME"
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.Fn TAILQ_INSERT_TAIL "TAILQ_HEAD *head" "TYPE *elm" "TAILQ_ENTRY NAME"
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.Fn TAILQ_LAST "TAILQ_HEAD *head" "HEADNAME"
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.Fn TAILQ_NEXT "TYPE *elm" "TAILQ_ENTRY NAME"
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.Fn TAILQ_PREV "TYPE *elm" "HEADNAME" "TAILQ_ENTRY NAME"
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.Fn TAILQ_REMOVE "TAILQ_HEAD *head" "TYPE *elm" "TAILQ_ENTRY NAME"
|
queue.3: Comment out text for functions not in glibc (related: 6559169cac)
===========
DESCRIPTION
===========
I'm documenting ``CIRCLEQ_*`` macros in queue.3. While writing
this, I noticed that the documentation for some types of
queues/lists talked about swapping contents of two lists, but only
for some of them. I then found that those macros (``*_SWAP``)
don't exist in my system (Debian), but exist in BSD, and I also
found that a previous commit (6559169cac) commented out a lot of
the *_SWAP macros documentation, but not all, and the reason was
that they were not present on glibc.
I checked that I didn't have any of the *_SWAP macros on my glibc,
so I think this is probably that the commit simply forgot to
comment some of
them.
=======
TESTING
=======
I did ``sudo make`` and then visualized the man page with
``man 3 queue``, and the changes looked good.
I also noticed that the subsection ``Tail queue example`` contents
were wrong, as they contained calls to CIRCLEQ_* macros. I will
address that in a future patch, before I submit the patch
documenting CIRCLEQ_*.
Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2020-08-04 09:40:41 +00:00
|
|
|
.\" .Fn TAILQ_SWAP "TAILQ_HEAD *head1" "TAILQ_HEAD *head2" "TYPE" "TAILQ_ENTRY NAME"
|
2015-02-07 06:39:47 +00:00
|
|
|
.\"
|
|
|
|
.Sh DESCRIPTION
|
2020-08-24 06:50:23 +00:00
|
|
|
These macros define and operate on five types of data structures:
|
|
|
|
singly-linked lists, singly-linked tail queues, lists, tail queues, and
|
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|
|
circular queues.
|
|
|
|
All five structures support the following functionality:
|
2017-08-25 18:54:52 +00:00
|
|
|
.Pp
|
2015-02-07 06:39:47 +00:00
|
|
|
.Bl -enum -compact -offset indent
|
|
|
|
.It
|
2004-11-03 13:51:07 +00:00
|
|
|
Insertion of a new entry at the head of the list.
|
2015-02-07 06:39:47 +00:00
|
|
|
.It
|
2004-11-03 13:51:07 +00:00
|
|
|
Insertion of a new entry after any element in the list.
|
2015-02-07 06:39:47 +00:00
|
|
|
.It
|
|
|
|
O(1) removal of an entry from the head of the list.
|
|
|
|
.It
|
2004-11-03 13:51:07 +00:00
|
|
|
Forward traversal through the list.
|
queue.3: Comment out text for functions not in glibc (related: 6559169cac)
===========
DESCRIPTION
===========
I'm documenting ``CIRCLEQ_*`` macros in queue.3. While writing
this, I noticed that the documentation for some types of
queues/lists talked about swapping contents of two lists, but only
for some of them. I then found that those macros (``*_SWAP``)
don't exist in my system (Debian), but exist in BSD, and I also
found that a previous commit (6559169cac) commented out a lot of
the *_SWAP macros documentation, but not all, and the reason was
that they were not present on glibc.
I checked that I didn't have any of the *_SWAP macros on my glibc,
so I think this is probably that the commit simply forgot to
comment some of
them.
=======
TESTING
=======
I did ``sudo make`` and then visualized the man page with
``man 3 queue``, and the changes looked good.
I also noticed that the subsection ``Tail queue example`` contents
were wrong, as they contained calls to CIRCLEQ_* macros. I will
address that in a future patch, before I submit the patch
documenting CIRCLEQ_*.
Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2020-08-04 09:40:41 +00:00
|
|
|
.\" .It
|
|
|
|
.\" Swapping the contents of two lists.
|
2015-02-07 06:39:47 +00:00
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
Singly-linked lists are the simplest of the four data structures
|
|
|
|
and support only the above functionality.
|
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|
|
Singly-linked lists are ideal for applications with large datasets
|
|
|
|
and few or no removals,
|
|
|
|
or for implementing a LIFO queue.
|
|
|
|
Singly-linked lists add the following functionality:
|
2017-08-25 18:54:52 +00:00
|
|
|
.Pp
|
2015-02-07 06:39:47 +00:00
|
|
|
.Bl -enum -compact -offset indent
|
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|
.It
|
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|
O(n) removal of any entry in the list.
|
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
Singly-linked tail queues add the following functionality:
|
2017-08-25 18:54:52 +00:00
|
|
|
.Pp
|
2015-02-07 06:39:47 +00:00
|
|
|
.Bl -enum -compact -offset indent
|
|
|
|
.It
|
2004-11-03 13:51:07 +00:00
|
|
|
Entries can be added at the end of a list.
|
2015-02-07 06:39:47 +00:00
|
|
|
.It
|
|
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|
O(n) removal of any entry in the list.
|
|
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|
.It
|
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|
|
They may be concatenated.
|
|
|
|
.El
|
2017-08-25 18:54:52 +00:00
|
|
|
.Pp
|
2004-11-03 13:51:07 +00:00
|
|
|
However:
|
2017-08-25 18:54:52 +00:00
|
|
|
.Pp
|
2015-02-07 06:39:47 +00:00
|
|
|
.Bl -enum -compact -offset indent
|
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.It
|
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All list insertions must specify the head of the list.
|
|
|
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.It
|
2004-11-03 13:51:07 +00:00
|
|
|
Each head entry requires two pointers rather than one.
|
2015-02-07 06:39:47 +00:00
|
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|
.It
|
2004-11-03 13:51:07 +00:00
|
|
|
Code size is about 15% greater and operations run about 20% slower
|
2015-02-07 06:39:47 +00:00
|
|
|
than singly-linked lists.
|
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
Singly-linked tail queues are ideal for applications with large datasets and
|
|
|
|
few or no removals,
|
|
|
|
or for implementing a FIFO queue.
|
|
|
|
.Pp
|
|
|
|
All doubly linked types of data structures (lists and tail queues)
|
|
|
|
additionally allow:
|
2017-08-25 18:54:52 +00:00
|
|
|
.Pp
|
2015-02-07 06:39:47 +00:00
|
|
|
.Bl -enum -compact -offset indent
|
|
|
|
.It
|
|
|
|
Insertion of a new entry before any element in the list.
|
|
|
|
.It
|
|
|
|
O(1) removal of any entry in the list.
|
|
|
|
.El
|
2017-08-25 18:54:52 +00:00
|
|
|
.Pp
|
2015-02-07 06:39:47 +00:00
|
|
|
However:
|
2017-08-25 18:54:52 +00:00
|
|
|
.Pp
|
2015-02-07 06:39:47 +00:00
|
|
|
.Bl -enum -compact -offset indent
|
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.It
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Each element requires two pointers rather than one.
|
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.It
|
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|
Code size and execution time of operations (except for removal) is about
|
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|
twice that of the singly-linked data-structures.
|
|
|
|
.El
|
|
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|
.Pp
|
|
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|
Linked lists are the simplest of the doubly linked data structures.
|
|
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|
They add the following functionality over the above:
|
2017-08-25 18:54:52 +00:00
|
|
|
.Pp
|
2015-02-07 06:39:47 +00:00
|
|
|
.Bl -enum -compact -offset indent
|
|
|
|
.It
|
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They may be traversed backwards.
|
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|
.El
|
2017-08-25 18:54:52 +00:00
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.Pp
|
2015-02-07 06:39:47 +00:00
|
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However:
|
2017-08-25 18:54:52 +00:00
|
|
|
.Pp
|
2015-02-07 06:39:47 +00:00
|
|
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.Bl -enum -compact -offset indent
|
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.It
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To traverse backwards, an entry to begin the traversal and the list in
|
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|
which it is contained must be specified.
|
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|
.El
|
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.Pp
|
|
|
|
Tail queues add the following functionality:
|
2020-08-24 15:06:59 +00:00
|
|
|
.Pp
|
2015-02-07 06:39:47 +00:00
|
|
|
.Bl -enum -compact -offset indent
|
|
|
|
.It
|
2004-11-03 13:51:07 +00:00
|
|
|
Entries can be added at the end of a list.
|
2015-02-07 06:39:47 +00:00
|
|
|
.It
|
|
|
|
They may be traversed backwards, from tail to head.
|
|
|
|
.It
|
|
|
|
They may be concatenated.
|
|
|
|
.El
|
2017-08-25 18:54:52 +00:00
|
|
|
.Pp
|
2004-11-03 13:51:07 +00:00
|
|
|
However:
|
2017-08-25 18:54:52 +00:00
|
|
|
.Pp
|
2015-02-07 06:39:47 +00:00
|
|
|
.Bl -enum -compact -offset indent
|
|
|
|
.It
|
2004-11-03 13:51:07 +00:00
|
|
|
All list insertions and removals must specify the head of the list.
|
2015-02-07 06:39:47 +00:00
|
|
|
.It
|
2004-11-03 13:51:07 +00:00
|
|
|
Each head entry requires two pointers rather than one.
|
2015-02-07 06:39:47 +00:00
|
|
|
.It
|
|
|
|
Code size is about 15% greater and operations run about 20% slower
|
|
|
|
than singly-linked lists.
|
|
|
|
.El
|
2020-08-24 07:02:54 +00:00
|
|
|
.Pp
|
2020-08-24 06:50:23 +00:00
|
|
|
Circular queues add the following functionality over the above:
|
2020-08-24 07:02:54 +00:00
|
|
|
.Pp
|
2020-08-24 06:50:23 +00:00
|
|
|
.Bl -enum -compact -offset indent
|
|
|
|
.It
|
|
|
|
The first and last entries are connected.
|
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
However:
|
|
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|
.Pp
|
|
|
|
.Bl -enum -compact -offset indent
|
|
|
|
.It
|
|
|
|
The termination condition for traversal is more complex.
|
|
|
|
.It
|
|
|
|
Code size is about 40% greater and operations run about 45% slower than lists.
|
|
|
|
.El
|
2015-02-07 06:39:47 +00:00
|
|
|
.Pp
|
2004-11-03 13:51:07 +00:00
|
|
|
In the macro definitions,
|
2015-02-07 06:39:47 +00:00
|
|
|
.Fa TYPE
|
|
|
|
is the name of a user defined structure,
|
2004-11-03 13:51:07 +00:00
|
|
|
that must contain a field of type
|
2015-02-07 06:39:47 +00:00
|
|
|
.Li SLIST_ENTRY ,
|
|
|
|
.Li STAILQ_ENTRY ,
|
|
|
|
.Li LIST_ENTRY ,
|
|
|
|
.Li TAILQ_ENTRY ,
|
2020-08-24 06:50:23 +00:00
|
|
|
or
|
|
|
|
.Li CIRCLEQ_ENTRY ,
|
2004-11-03 13:51:07 +00:00
|
|
|
named
|
2015-02-07 06:39:47 +00:00
|
|
|
.Fa NAME .
|
2004-11-03 13:51:07 +00:00
|
|
|
The argument
|
2015-02-07 06:39:47 +00:00
|
|
|
.Fa HEADNAME
|
|
|
|
is the name of a user defined structure that must be declared
|
2004-11-03 13:51:07 +00:00
|
|
|
using the macros
|
2015-02-07 06:39:47 +00:00
|
|
|
.Li SLIST_HEAD ,
|
|
|
|
.Li STAILQ_HEAD ,
|
|
|
|
.Li LIST_HEAD ,
|
2020-08-24 06:50:23 +00:00
|
|
|
.Li TAILQ_HEAD ,
|
2004-11-03 13:51:07 +00:00
|
|
|
or
|
2020-08-24 06:50:23 +00:00
|
|
|
.Li CIRCLEQ_HEAD .
|
2004-11-03 13:51:07 +00:00
|
|
|
See the examples below for further explanation of how these
|
|
|
|
macros are used.
|
2015-02-07 07:08:17 +00:00
|
|
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.Ss Tail queues
|
2015-02-07 06:39:47 +00:00
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A tail queue is headed by a structure defined by the
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.Nm TAILQ_HEAD
|
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macro.
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This structure contains a pair of pointers,
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one to the first element in the tail queue and the other to
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the last element in the tail queue.
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The elements are doubly linked so that an arbitrary element can be
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removed without traversing the tail queue.
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New elements can be added to the tail queue after an existing element,
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before an existing element, at the head of the tail queue,
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or at the end of the tail queue.
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A
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.Fa TAILQ_HEAD
|
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structure is declared as follows:
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.Bd -literal -offset indent
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TAILQ_HEAD(HEADNAME, TYPE) head;
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.Ed
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.Pp
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where
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.Li HEADNAME
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is the name of the structure to be defined, and
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.Li TYPE
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is the type of the elements to be linked into the tail queue.
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A pointer to the head of the tail queue can later be declared as:
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.Bd -literal -offset indent
|
2004-11-03 13:51:07 +00:00
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struct HEADNAME *headp;
|
2015-02-07 06:39:47 +00:00
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.Ed
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.Pp
|
2004-11-03 13:51:07 +00:00
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(The names
|
2015-02-07 06:39:47 +00:00
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.Li head
|
2004-11-03 13:51:07 +00:00
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and
|
2015-02-07 06:39:47 +00:00
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|
.Li headp
|
2004-11-03 13:51:07 +00:00
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are user selectable.)
|
2015-02-07 06:39:47 +00:00
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.Pp
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The macro
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.Nm TAILQ_HEAD_INITIALIZER
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evaluates to an initializer for the tail queue
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.Fa head .
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.Pp
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The macro
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.Nm TAILQ_CONCAT
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concatenates the tail queue headed by
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.Fa head2
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onto the end of the one headed by
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.Fa head1
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removing all entries from the former.
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.Pp
|
2004-11-03 13:51:07 +00:00
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The macro
|
2015-02-07 06:39:47 +00:00
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.Nm TAILQ_EMPTY
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evaluates to true if there are no items on the tail queue.
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.Pp
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The macro
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.Nm TAILQ_ENTRY
|
2004-11-03 13:51:07 +00:00
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declares a structure that connects the elements in
|
2015-02-07 06:39:47 +00:00
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the tail queue.
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.Pp
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The macro
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.Nm TAILQ_FIRST
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returns the first item on the tail queue or NULL if the tail queue
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is empty.
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.Pp
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The macro
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.Nm TAILQ_FOREACH
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traverses the tail queue referenced by
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.Fa head
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in the forward direction, assigning each element in turn to
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.Fa var .
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.Fa var
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is set to
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.Dv NULL
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if the loop completes normally, or if there were no elements.
|
2015-02-07 07:05:23 +00:00
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.\" .Pp
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.\" The macro
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.\" .Nm TAILQ_FOREACH_FROM
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.\" behaves identically to
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.\" .Nm TAILQ_FOREACH
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.\" when
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.\" .Fa var
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.\" is NULL, else it treats
|
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.\" .Fa var
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.\" as a previously found TAILQ element and begins the loop at
|
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.\" .Fa var
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.\" instead of the first element in the TAILQ referenced by
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.\" .Fa head .
|
2015-02-07 06:39:47 +00:00
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.Pp
|
2004-11-03 13:51:07 +00:00
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The macro
|
2015-02-07 06:39:47 +00:00
|
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|
.Nm TAILQ_FOREACH_REVERSE
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|
traverses the tail queue referenced by
|
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.Fa head
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in the reverse direction, assigning each element in turn to
|
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.Fa var .
|
2015-02-07 07:05:23 +00:00
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.\" .Pp
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.\" The macro
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|
.\" .Nm TAILQ_FOREACH_REVERSE_FROM
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|
.\" behaves identically to
|
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|
.\" .Nm TAILQ_FOREACH_REVERSE
|
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.\" when
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.\" .Fa var
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.\" is NULL, else it treats
|
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.\" .Fa var
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.\" as a previously found TAILQ element and begins the reverse loop at
|
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.\" .Fa var
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.\" instead of the last element in the TAILQ referenced by
|
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.\" .Fa head .
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.\" .Pp
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|
.\" The macros
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|
.\" .Nm TAILQ_FOREACH_SAFE
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.\" and
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|
.\" .Nm TAILQ_FOREACH_REVERSE_SAFE
|
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|
.\" traverse the list referenced by
|
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|
.\" .Fa head
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|
.\" in the forward or reverse direction respectively,
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|
.\" assigning each element in turn to
|
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|
.\" .Fa var .
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.\" However, unlike their unsafe counterparts,
|
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|
.\" .Nm TAILQ_FOREACH
|
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.\" and
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.\" .Nm TAILQ_FOREACH_REVERSE
|
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|
.\" permit to both remove
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.\" .Fa var
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|
.\" as well as free it from within the loop safely without interfering with the
|
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|
.\" traversal.
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.\" .Pp
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.\" The macro
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|
.\" .Nm TAILQ_FOREACH_FROM_SAFE
|
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|
.\" behaves identically to
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.\" .Nm TAILQ_FOREACH_SAFE
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.\" when
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.\" .Fa var
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.\" is NULL, else it treats
|
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.\" .Fa var
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.\" as a previously found TAILQ element and begins the loop at
|
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.\" .Fa var
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.\" instead of the first element in the TAILQ referenced by
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.\" .Fa head .
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.\" .Pp
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|
.\" The macro
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|
.\" .Nm TAILQ_FOREACH_REVERSE_FROM_SAFE
|
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|
.\" behaves identically to
|
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|
|
.\" .Nm TAILQ_FOREACH_REVERSE_SAFE
|
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|
.\" when
|
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|
.\" .Fa var
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|
.\" is NULL, else it treats
|
|
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|
.\" .Fa var
|
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|
.\" as a previously found TAILQ element and begins the reverse loop at
|
|
|
|
.\" .Fa var
|
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|
.\" instead of the last element in the TAILQ referenced by
|
|
|
|
.\" .Fa head .
|
2015-02-07 06:39:47 +00:00
|
|
|
.Pp
|
|
|
|
The macro
|
|
|
|
.Nm TAILQ_INIT
|
|
|
|
initializes the tail queue referenced by
|
|
|
|
.Fa head .
|
|
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|
.Pp
|
|
|
|
The macro
|
|
|
|
.Nm TAILQ_INSERT_HEAD
|
2004-11-03 13:51:07 +00:00
|
|
|
inserts the new element
|
2015-02-07 06:39:47 +00:00
|
|
|
.Fa elm
|
|
|
|
at the head of the tail queue.
|
|
|
|
.Pp
|
2004-11-03 13:51:07 +00:00
|
|
|
The macro
|
2015-02-07 06:39:47 +00:00
|
|
|
.Nm TAILQ_INSERT_TAIL
|
2004-11-03 13:51:07 +00:00
|
|
|
inserts the new element
|
2015-02-07 06:39:47 +00:00
|
|
|
.Fa elm
|
|
|
|
at the end of the tail queue.
|
|
|
|
.Pp
|
2004-11-03 13:51:07 +00:00
|
|
|
The macro
|
2015-02-07 06:39:47 +00:00
|
|
|
.Nm TAILQ_INSERT_AFTER
|
2004-11-03 13:51:07 +00:00
|
|
|
inserts the new element
|
2015-02-07 06:39:47 +00:00
|
|
|
.Fa elm
|
2004-11-03 13:51:07 +00:00
|
|
|
after the element
|
2015-02-07 06:39:47 +00:00
|
|
|
.Fa listelm .
|
|
|
|
.Pp
|
2004-11-03 13:51:07 +00:00
|
|
|
The macro
|
2015-02-07 06:39:47 +00:00
|
|
|
.Nm TAILQ_INSERT_BEFORE
|
2004-11-03 13:51:07 +00:00
|
|
|
inserts the new element
|
2015-02-07 06:39:47 +00:00
|
|
|
.Fa elm
|
2004-11-03 13:51:07 +00:00
|
|
|
before the element
|
2015-02-07 06:39:47 +00:00
|
|
|
.Fa listelm .
|
|
|
|
.Pp
|
|
|
|
The macro
|
|
|
|
.Nm TAILQ_LAST
|
|
|
|
returns the last item on the tail queue.
|
|
|
|
If the tail queue is empty the return value is
|
|
|
|
.Dv NULL .
|
|
|
|
.Pp
|
2004-11-03 13:51:07 +00:00
|
|
|
The macro
|
2015-02-07 06:39:47 +00:00
|
|
|
.Nm TAILQ_NEXT
|
|
|
|
returns the next item on the tail queue, or NULL if this item is the last.
|
|
|
|
.Pp
|
|
|
|
The macro
|
|
|
|
.Nm TAILQ_PREV
|
|
|
|
returns the previous item on the tail queue, or NULL if this item
|
|
|
|
is the first.
|
|
|
|
.Pp
|
|
|
|
The macro
|
|
|
|
.Nm TAILQ_REMOVE
|
2004-11-03 13:51:07 +00:00
|
|
|
removes the element
|
2015-02-07 06:39:47 +00:00
|
|
|
.Fa elm
|
|
|
|
from the tail queue.
|
queue.3: Comment out text for functions not in glibc (related: 6559169cac)
===========
DESCRIPTION
===========
I'm documenting ``CIRCLEQ_*`` macros in queue.3. While writing
this, I noticed that the documentation for some types of
queues/lists talked about swapping contents of two lists, but only
for some of them. I then found that those macros (``*_SWAP``)
don't exist in my system (Debian), but exist in BSD, and I also
found that a previous commit (6559169cac) commented out a lot of
the *_SWAP macros documentation, but not all, and the reason was
that they were not present on glibc.
I checked that I didn't have any of the *_SWAP macros on my glibc,
so I think this is probably that the commit simply forgot to
comment some of
them.
=======
TESTING
=======
I did ``sudo make`` and then visualized the man page with
``man 3 queue``, and the changes looked good.
I also noticed that the subsection ``Tail queue example`` contents
were wrong, as they contained calls to CIRCLEQ_* macros. I will
address that in a future patch, before I submit the patch
documenting CIRCLEQ_*.
Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2020-08-04 09:40:41 +00:00
|
|
|
.\" .Pp
|
|
|
|
.\" The macro
|
|
|
|
.\" .Nm TAILQ_SWAP
|
|
|
|
.\" swaps the contents of
|
|
|
|
.\" .Fa head1
|
|
|
|
.\" and
|
|
|
|
.\" .Fa head2 .
|
2020-10-10 19:02:27 +00:00
|
|
|
.Pp
|
|
|
|
See the EXAMPLES section below for an example program using a tail queue.
|
|
|
|
.Sh EXAMPLES
|
|
|
|
.Ss Tail queue example
|
|
|
|
.Bd -literal
|
|
|
|
#include <stddef.h>
|
|
|
|
#include <stdio.h>
|
|
|
|
#include <stdlib.h>
|
|
|
|
#include <sys/queue.h>
|
|
|
|
|
|
|
|
struct entry {
|
|
|
|
int data;
|
|
|
|
TAILQ_ENTRY(entry) entries; /* Tail queue. */
|
|
|
|
};
|
|
|
|
|
|
|
|
TAILQ_HEAD(tailhead, entry);
|
|
|
|
|
|
|
|
int
|
|
|
|
main(void)
|
|
|
|
{
|
|
|
|
struct entry *n1, *n2, *n3, *np;
|
|
|
|
struct tailhead head; /* Tail queue head. */
|
|
|
|
int i;
|
|
|
|
|
|
|
|
TAILQ_INIT(&head); /* Initialize the queue. */
|
|
|
|
|
|
|
|
n1 = malloc(sizeof(struct entry)); /* Insert at the head. */
|
|
|
|
TAILQ_INSERT_HEAD(&head, n1, entries);
|
|
|
|
|
|
|
|
n1 = malloc(sizeof(struct entry)); /* Insert at the tail. */
|
|
|
|
TAILQ_INSERT_TAIL(&head, n1, entries);
|
|
|
|
|
|
|
|
n2 = malloc(sizeof(struct entry)); /* Insert after. */
|
|
|
|
TAILQ_INSERT_AFTER(&head, n1, n2, entries);
|
|
|
|
|
|
|
|
n3 = malloc(sizeof(struct entry)); /* Insert before. */
|
|
|
|
TAILQ_INSERT_BEFORE(n2, n3, entries);
|
|
|
|
|
|
|
|
TAILQ_REMOVE(&head, n2, entries); /* Deletion. */
|
|
|
|
free(n2);
|
|
|
|
/* Forward traversal. */
|
|
|
|
i = 0;
|
|
|
|
TAILQ_FOREACH(np, &head, entries)
|
|
|
|
np->data = i++;
|
|
|
|
/* Reverse traversal. */
|
|
|
|
TAILQ_FOREACH_REVERSE(np, &head, tailhead, entries)
|
|
|
|
printf("%i\en", np->data);
|
|
|
|
/* TailQ Deletion. */
|
|
|
|
n1 = TAILQ_FIRST(&head);
|
|
|
|
while (n1 != NULL) {
|
|
|
|
n2 = TAILQ_NEXT(n1, entries);
|
|
|
|
free(n1);
|
|
|
|
n1 = n2;
|
|
|
|
}
|
|
|
|
TAILQ_INIT(&head);
|
|
|
|
|
|
|
|
exit(EXIT_SUCCESS);
|
|
|
|
}
|
|
|
|
.Ed
|
2015-02-07 07:11:04 +00:00
|
|
|
.Sh CONFORMING TO
|
2016-02-15 13:40:13 +00:00
|
|
|
Not in POSIX.1, POSIX.1-2001 or POSIX.1-2008.
|
2015-02-07 07:11:04 +00:00
|
|
|
Present on the BSDs.
|
2015-02-07 06:39:47 +00:00
|
|
|
.Nm queue
|
|
|
|
functions first appeared in
|
|
|
|
.Bx 4.4 .
|
2017-04-24 19:14:58 +00:00
|
|
|
.Sh SEE ALSO
|
2020-10-23 14:57:37 +00:00
|
|
|
.Xr circleq 3
|
2017-04-24 19:14:58 +00:00
|
|
|
.Xr insque 3
|
2020-10-20 21:31:08 +00:00
|
|
|
.Xr list 3
|
2020-10-22 12:38:22 +00:00
|
|
|
.Xr slist 3
|
2015-04-18 08:55:56 +00:00
|
|
|
.\" .Xr tree 3
|