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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-24 04:52:22 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-24 04:52:22 +0000
commit3d08cd331c1adcf0d917392f7e527b3f00511748 (patch)
tree312f0d1e1632f48862f044b8bb87e602dcffb5f9 /man/man3/stailq.3
parentAdding debian version 6.7-2. (diff)
downloadmanpages-3d08cd331c1adcf0d917392f7e527b3f00511748.tar.xz
manpages-3d08cd331c1adcf0d917392f7e527b3f00511748.zip
Merging upstream version 6.8.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+.\" Copyright (c) 1993
+.\" The Regents of the University of California. All rights reserved.
+.\" and Copyright (c) 2020 by Alejandro Colomar <alx@kernel.org>
+.\"
+.\" SPDX-License-Identifier: BSD-3-Clause
+.\"
+.\"
+.TH STAILQ 3 2024-05-02 "Linux man-pages (unreleased)"
+.SH NAME
+.\"SIMPLEQ_CONCAT,
+SIMPLEQ_EMPTY,
+SIMPLEQ_ENTRY,
+SIMPLEQ_FIRST,
+SIMPLEQ_FOREACH,
+.\"SIMPLEQ_FOREACH_FROM,
+.\"SIMPLEQ_FOREACH_FROM_SAFE,
+.\"SIMPLEQ_FOREACH_SAFE,
+SIMPLEQ_HEAD,
+SIMPLEQ_HEAD_INITIALIZER,
+SIMPLEQ_INIT,
+SIMPLEQ_INSERT_AFTER,
+SIMPLEQ_INSERT_HEAD,
+SIMPLEQ_INSERT_TAIL,
+.\"SIMPLEQ_LAST,
+SIMPLEQ_NEXT,
+SIMPLEQ_REMOVE,
+.\"SIMPLEQ_REMOVE_AFTER,
+SIMPLEQ_REMOVE_HEAD,
+.\"SIMPLEQ_SWAP,
+STAILQ_CONCAT,
+STAILQ_EMPTY,
+STAILQ_ENTRY,
+STAILQ_FIRST,
+STAILQ_FOREACH,
+.\"STAILQ_FOREACH_FROM,
+.\"STAILQ_FOREACH_FROM_SAFE,
+.\"STAILQ_FOREACH_SAFE,
+STAILQ_HEAD,
+STAILQ_HEAD_INITIALIZER,
+STAILQ_INIT,
+STAILQ_INSERT_AFTER,
+STAILQ_INSERT_HEAD,
+STAILQ_INSERT_TAIL,
+.\"STAILQ_LAST,
+STAILQ_NEXT,
+STAILQ_REMOVE,
+.\"STAILQ_REMOVE_AFTER,
+STAILQ_REMOVE_HEAD,
+.\"STAILQ_SWAP
+\- implementation of a singly linked tail queue
+.SH LIBRARY
+Standard C library
+.RI ( libc ", " \-lc )
+.SH SYNOPSIS
+.nf
+.B #include <sys/queue.h>
+.P
+.B STAILQ_ENTRY(TYPE);
+.P
+.B STAILQ_HEAD(HEADNAME, TYPE);
+.BI "STAILQ_HEAD STAILQ_HEAD_INITIALIZER(STAILQ_HEAD " head );
+.BI "void STAILQ_INIT(STAILQ_HEAD *" head );
+.P
+.BI "int STAILQ_EMPTY(STAILQ_HEAD *" head );
+.P
+.BI "void STAILQ_INSERT_HEAD(STAILQ_HEAD *" head ,
+.BI " struct TYPE *" elm ", STAILQ_ENTRY " NAME );
+.BI "void STAILQ_INSERT_TAIL(STAILQ_HEAD *" head ,
+.BI " struct TYPE *" elm ", STAILQ_ENTRY " NAME );
+.BI "void STAILQ_INSERT_AFTER(STAILQ_HEAD *" head ", struct TYPE *" listelm ,
+.BI " struct TYPE *" elm ", STAILQ_ENTRY " NAME );
+.P
+.BI "struct TYPE *STAILQ_FIRST(STAILQ_HEAD *" head );
+.\" .BI "struct TYPE *STAILQ_LAST(STAILQ_HEAD *" head ", struct TYPE *" elm ,
+.\" .BI " STAILQ_ENTRY " NAME );
+.BI "struct TYPE *STAILQ_NEXT(struct TYPE *" elm ", STAILQ_ENTRY " NAME );
+.P
+.BI "STAILQ_FOREACH(struct TYPE *" var ", STAILQ_HEAD *" head ", STAILQ_ENTRY " NAME );
+.\" .BI "STAILQ_FOREACH_FROM(struct TYPE *" var ", STAILQ_HEAD *" head ,
+.\" .BI " STAILQ_ENTRY " NAME );
+.\" .P
+.\" .BI "STAILQ_FOREACH_SAFE(struct TYPE *" var ", STAILQ_HEAD *" head ,
+.\" .BI " STAILQ_ENTRY " NAME ", struct TYPE *" temp_var );
+.\" .BI "STAILQ_FOREACH_FROM_SAFE(struct TYPE *" var ", STAILQ_HEAD *" head ,
+.\" .BI " STAILQ_ENTRY " NAME ", struct TYPE *" temp_var );
+.P
+.BI "void STAILQ_REMOVE(STAILQ_HEAD *" head ", struct TYPE *" elm ", TYPE,"
+.BI " STAILQ_ENTRY " NAME );
+.BI "void STAILQ_REMOVE_HEAD(STAILQ_HEAD *" head ,
+.BI " STAILQ_ENTRY " NAME );
+.\" .BI "void STAILQ_REMOVE_AFTER(STAILQ_HEAD *" head ", struct TYPE *" elm ,
+.\" .BI " STAILQ_ENTRY " NAME );
+.P
+.BI "void STAILQ_CONCAT(STAILQ_HEAD *" head1 ", STAILQ_HEAD *" head2 );
+.\" .BI "void STAILQ_SWAP(STAILQ_HEAD *" head1 ", STAILQ_HEAD *" head2 ,
+.\" .BI " STAILQ_ENTRY " NAME );
+.fi
+.IR Note :
+Identical macros prefixed with SIMPLEQ instead of STAILQ exist; see NOTES.
+.SH DESCRIPTION
+These macros define and operate on singly linked tail queues.
+.P
+In the macro definitions,
+.I TYPE
+is the name of a user-defined structure,
+that must contain a field of type
+.IR STAILQ_ENTRY ,
+named
+.IR NAME .
+The argument
+.I HEADNAME
+is the name of a user-defined structure that must be declared
+using the macro
+.BR STAILQ_HEAD ().
+.SS Creation
+A singly linked tail queue is headed by a structure defined by the
+.BR STAILQ_HEAD ()
+macro.
+This structure contains a pair of pointers,
+one to the first element in the tail queue and the other to
+the last element in the tail queue.
+The elements are singly linked for minimum space and pointer
+manipulation overhead at the expense of O(n) removal for arbitrary elements.
+New elements can be added to the tail queue after an existing element,
+at the head of the tail queue, or at the end of the tail queue.
+A
+.I STAILQ_HEAD
+structure is declared as follows:
+.P
+.in +4
+.EX
+STAILQ_HEAD(HEADNAME, TYPE) head;
+.EE
+.in
+.P
+where
+.I struct HEADNAME
+is the structure to be defined, and
+.I struct TYPE
+is the type of the elements to be linked into the tail queue.
+A pointer to the head of the tail queue can later be declared as:
+.P
+.in +4
+.EX
+struct HEADNAME *headp;
+.EE
+.in
+.P
+(The names
+.I head
+and
+.I headp
+are user selectable.)
+.P
+.BR STAILQ_ENTRY ()
+declares a structure that connects the elements in the tail queue.
+.P
+.BR STAILQ_HEAD_INITIALIZER ()
+evaluates to an initializer for the tail queue
+.IR head .
+.P
+.BR STAILQ_INIT ()
+initializes the tail queue referenced by
+.IR head .
+.P
+.BR STAILQ_EMPTY ()
+evaluates to true if there are no items on the tail queue.
+.SS Insertion
+.BR STAILQ_INSERT_HEAD ()
+inserts the new element
+.I elm
+at the head of the tail queue.
+.P
+.BR STAILQ_INSERT_TAIL ()
+inserts the new element
+.I elm
+at the end of the tail queue.
+.P
+.BR STAILQ_INSERT_AFTER ()
+inserts the new element
+.I elm
+after the element
+.IR listelm .
+.SS Traversal
+.BR STAILQ_FIRST ()
+returns the first item on the tail queue or NULL if the tail queue is empty.
+.\" .P
+.\" .BR STAILQ_LAST ()
+.\" returns the last item on the tail queue.
+.\" If the tail queue is empty the return value is NULL .
+.P
+.BR STAILQ_NEXT ()
+returns the next item on the tail queue, or NULL this item is the last.
+.P
+.BR STAILQ_FOREACH ()
+traverses the tail queue referenced by
+.I head
+in the forward direction,
+assigning each element in turn to
+.IR var .
+.\" .P
+.\" .BR STAILQ_FOREACH_FROM ()
+.\" behaves identically to
+.\" .BR STAILQ_FOREACH ()
+.\" when
+.\" .I var
+.\" is NULL, else it treats
+.\" .I var
+.\" as a previously found STAILQ element and begins the loop at
+.\" .I var
+.\" instead of the first element in the STAILQ referenced by
+.\" .IR head .
+.\" .P
+.\" .BR STAILQ_FOREACH_SAFE ()
+.\" traverses the tail queue referenced by
+.\" .I head
+.\" in the forward direction, assigning each element
+.\" in turn to
+.\" .IR var .
+.\" However, unlike
+.\" .BR STAILQ_FOREACH ()
+.\" here it is permitted to both remove
+.\" .I var
+.\" as well as free it from within the loop safely without interfering with the
+.\" traversal.
+.\" .P
+.\" .BR STAILQ_FOREACH_FROM_SAFE ()
+.\" behaves identically to
+.\" .BR STAILQ_FOREACH_SAFE ()
+.\" when
+.\" .I var
+.\" is NULL, else it treats
+.\" .I var
+.\" as a previously found STAILQ element and begins the loop at
+.\" .I var
+.\" instead of the first element in the STAILQ referenced by
+.\" .IR head .
+.SS Removal
+.BR STAILQ_REMOVE ()
+removes the element
+.I elm
+from the tail queue.
+.P
+.BR STAILQ_REMOVE_HEAD ()
+removes the element at the head of the tail queue.
+For optimum efficiency,
+elements being removed from the head of the tail queue should
+use this macro explicitly rather than the generic
+.BR STAILQ_REMOVE ()
+macro.
+.\" .P
+.\" .BR STAILQ_REMOVE_AFTER ()
+.\" removes the element after
+.\" .I elm
+.\" from the tail queue.
+.\" Unlike
+.\" .BR STAILQ_REMOVE (),
+.\" this macro does not traverse the entire tail queue.
+.SS Other features
+.BR STAILQ_CONCAT ()
+concatenates the tail queue headed by
+.I head2
+onto the end of the one headed by
+.I head1
+removing all entries from the former.
+.\" .P
+.\" .BR STAILQ_SWAP ()
+.\" swaps the contents of
+.\" .I head1
+.\" and
+.\" .IR head2 .
+.SH RETURN VALUE
+.BR STAILQ_EMPTY ()
+returns nonzero if the queue is empty,
+and zero if the queue contains at least one entry.
+.P
+.BR STAILQ_FIRST (),
+and
+.BR STAILQ_NEXT ()
+return a pointer to the first or next
+.I TYPE
+structure, respectively.
+.P
+.BR STAILQ_HEAD_INITIALIZER ()
+returns an initializer that can be assigned to the queue
+.IR head .
+.SH VERSIONS
+Some BSDs provide SIMPLEQ instead of STAILQ.
+They are identical, but for historical reasons
+they were named differently on different BSDs.
+STAILQ originated on FreeBSD, and SIMPLEQ originated on NetBSD.
+For compatibility reasons, some systems provide both sets of macros.
+glibc provides both STAILQ and SIMPLEQ,
+which are identical except for a missing SIMPLEQ equivalent to
+.BR STAILQ_CONCAT ().
+.SH BUGS
+.BR STAILQ_FOREACH ()
+doesn't allow
+.I var
+to be removed or freed within the loop,
+as it would interfere with the traversal.
+.BR STAILQ_FOREACH_SAFE (),
+which is present on the BSDs but is not present in glibc,
+fixes this limitation by allowing
+.I var
+to safely be removed from the list and freed from within the loop
+without interfering with the traversal.
+.SH STANDARDS
+BSD.
+.SH HISTORY
+4.4BSD.
+.SH EXAMPLES
+.\" SRC BEGIN (stailq.c)
+.EX
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/queue.h>
+\&
+struct entry {
+ int data;
+ STAILQ_ENTRY(entry) entries; /* Singly linked tail queue */
+};
+\&
+STAILQ_HEAD(stailhead, entry);
+\&
+int
+main(void)
+{
+ struct entry *n1, *n2, *n3, *np;
+ struct stailhead head; /* Singly linked tail queue
+ head */
+\&
+ STAILQ_INIT(&head); /* Initialize the queue */
+\&
+ n1 = malloc(sizeof(struct entry)); /* Insert at the head */
+ STAILQ_INSERT_HEAD(&head, n1, entries);
+\&
+ n1 = malloc(sizeof(struct entry)); /* Insert at the tail */
+ STAILQ_INSERT_TAIL(&head, n1, entries);
+\&
+ n2 = malloc(sizeof(struct entry)); /* Insert after */
+ STAILQ_INSERT_AFTER(&head, n1, n2, entries);
+\&
+ STAILQ_REMOVE(&head, n2, entry, entries); /* Deletion */
+ free(n2);
+\&
+ n3 = STAILQ_FIRST(&head);
+ STAILQ_REMOVE_HEAD(&head, entries); /* Deletion from the head */
+ free(n3);
+\&
+ n1 = STAILQ_FIRST(&head);
+ n1\->data = 0;
+ for (unsigned int i = 1; i < 5; i++) {
+ n1 = malloc(sizeof(struct entry));
+ STAILQ_INSERT_HEAD(&head, n1, entries);
+ n1\->data = i;
+ }
+ /* Forward traversal */
+ STAILQ_FOREACH(np, &head, entries)
+ printf("%i\en", np\->data);
+ /* TailQ deletion */
+ n1 = STAILQ_FIRST(&head);
+ while (n1 != NULL) {
+ n2 = STAILQ_NEXT(n1, entries);
+ free(n1);
+ n1 = n2;
+ }
+ STAILQ_INIT(&head);
+\&
+ exit(EXIT_SUCCESS);
+}
+.EE
+.\" SRC END
+.SH SEE ALSO
+.BR insque (3),
+.BR queue (7)