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Document LIST_FOREACH_SAFE in queue(3).

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Asked with "please" by Ruslan Ermilov.  I've always had a weakness
for "please".
This commit is contained in:
Bosko Milekic 2003-08-13 19:58:38 +00:00
parent 5402d8ec23
commit 4250a68e2d
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=118879
1 changed files with 24 additions and 1 deletions
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25
share/man/man3/queue.3
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@ -67,6 +67,7 @@
.Nm LIST_ENTRY ,
.Nm LIST_FIRST ,
.Nm LIST_FOREACH ,
.Nm LIST_FOREACH_SAFE ,
.Nm LIST_HEAD ,
.Nm LIST_HEAD_INITIALIZER ,
.Nm LIST_INIT ,
@ -130,6 +131,7 @@ lists and tail queues
.Fn LIST_ENTRY "TYPE"
.Fn LIST_FIRST "LIST_HEAD *head"
.Fn LIST_FOREACH "TYPE *var" "LIST_HEAD *head" "LIST_ENTRY NAME"
.Fn LIST_FOREACH_SAFE "TYPE *var" "LIST_HEAD *head" "LIST_ENTRY NAME" "TYPE *temp_var"
.Fn LIST_HEAD "HEADNAME" "TYPE"
.Fn LIST_HEAD_INITIALIZER "LIST_HEAD head"
.Fn LIST_INIT "LIST_HEAD *head"
@ -619,6 +621,19 @@ in the forward direction, assigning each element in turn to
.Fa var .
.Pp
The macro
.Nm LIST_FOREACH_SAFE
traverses the list referenced by
.Fa head
in the forward direction, assigning each element in turn to
.Fa var .
However, unlike
.Fn LIST_FOREACH
here it is permitted to both remove
.Fa var
as well as free it from within the loop safely without interfering with the
traversal.
.Pp
The macro
.Nm LIST_INIT
initializes the list referenced by
.Fa head .
@ -661,7 +676,7 @@ struct entry {
...
LIST_ENTRY(entry) entries; /* List. */
...
} *n1, *n2, *n3, *np;
} *n1, *n2, *n3, *np, *np_temp;
LIST_INIT(&head); /* Initialize the list. */
@ -680,6 +695,14 @@ free(n2);
LIST_FOREACH(np, &head, entries)
np-> ...
/* Safe forward traversal. */
LIST_FOREACH_SAFE(np, &head, entries, np_temp) {
np->do_stuff();
...
LIST_REMOVE(np, entries);
free(np);
}
while (!LIST_EMPTY(&head)) { /* List Deletion. */
n1 = LIST_FIRST(&head);
LIST_REMOVE(n1, entries);