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| author | Alejandro Colomar <colomar.6.4.3@gmail.com> | 2020-10-13 16:55:49 +0200 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2020-10-13 17:36:17 +0200 |
| commit | 46b0a9d69cc031e0cb64f0f7ba6fe7eb2aba3a57 (patch) | |
| tree | de992b9d7122d19d34b2f98fe6355e83e7586a93 /man3/queue.3 | |
| parent | 861b602b53cda7aa894cdddd20c2f6e37fe77b8a (diff) | |
| download | man-pages-46b0a9d69cc031e0cb64f0f7ba6fe7eb2aba3a57.tar.gz | |
queue.3: circleq: Complete example
Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Diffstat (limited to 'man3/queue.3')
| -rw-r--r-- | man3/queue.3 | 105 |
1 files changed, 56 insertions, 49 deletions
diff --git a/man3/queue.3 b/man3/queue.3 index 95bc7d5bc0..fed8d126f5 100644 --- a/man3/queue.3 +++ b/man3/queue.3 @@ -1318,55 +1318,6 @@ The macro removes the element .Fa elm from the circular queue. -.Ss Circular queue example -.Bd -literal -CIRCLEQ_HEAD(circleq, entry) head = - CIRCLEQ_HEAD_INITIALIZER(head); -struct circleq *headp; /* Circular queue head. */ -struct entry { - ... - CIRCLEQ_ENTRY(entry) entries; /* Circular queue. */ - ... -} *n1, *n2, *n3, *np; - -CIRCLEQ_INIT(&head); /* Initialize the queue. */ - -n1 = malloc(sizeof(struct entry)); /* Insert at the head. */ -CIRCLEQ_INSERT_HEAD(&head, n1, entries); - -n1 = malloc(sizeof(struct entry)); /* Insert at the tail. */ -CIRCLEQ_INSERT_TAIL(&head, n1, entries); - -n2 = malloc(sizeof(struct entry)); /* Insert after. */ -CIRCLEQ_INSERT_AFTER(&head, n1, n2, entries); - -n3 = malloc(sizeof(struct entry)); /* Insert before. */ -CIRCLEQ_INSERT_BEFORE(&head, n2, n3, entries); - -CIRCLEQ_REMOVE(&head, n2, entries); /* Deletion. */ -free(n2); - /* Forward traversal. */ -CIRCLEQ_FOREACH(np, &head, entries) - np\-> ... - /* Reverse traversal. */ -CIRCLEQ_FOREACH_REVERSE(np, &head, entries) - np\-> ... - /* CircleQ Deletion. */ -while (!CIRCLEQ_EMPTY(&head)) { - n1 = CIRCLEQ_FIRST(&head); - CIRCLEQ_REMOVE(&head, n1, entries); - free(n1); -} - /* Faster CircleQ Deletion. */ -n1 = CIRCLEQ_FIRST(&head); -while (n1 != (void *)&head) { - n2 = CIRCLEQ_NEXT(n1, entries); - free(n1); - n1 = n2; -} - -CIRCLEQ_INIT(&head); -.Ed .Sh EXAMPLES .Ss Singly-linked list example .Bd -literal @@ -1481,6 +1432,62 @@ main(void) exit(EXIT_SUCCESS); } .Ed +.Ss Circular queue example +.Bd -literal +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/queue.h> + +struct entry { + int data; + CIRCLEQ_ENTRY(entry) entries; /* Queue. */ +}; + +CIRCLEQ_HEAD(circlehead, entry); + +int +main(void) +{ + struct entry *n1, *n2, *n3, *np; + struct circlehead head; /* Queue head. */ + int i; + + CIRCLEQ_INIT(&head); /* Initialize the queue. */ + + n1 = malloc(sizeof(struct entry)); /* Insert at the head. */ + CIRCLEQ_INSERT_HEAD(&head, n1, entries); + + n1 = malloc(sizeof(struct entry)); /* Insert at the tail. */ + CIRCLEQ_INSERT_TAIL(&head, n1, entries); + + n2 = malloc(sizeof(struct entry)); /* Insert after. */ + CIRCLEQ_INSERT_AFTER(&head, n1, n2, entries); + + n3 = malloc(sizeof(struct entry)); /* Insert before. */ + CIRCLEQ_INSERT_BEFORE(&head, n2, n3, entries); + + CIRCLEQ_REMOVE(&head, n2, entries); /* Deletion. */ + free(n2); + /* Forward traversal. */ + i = 0; + CIRCLEQ_FOREACH(np, &head, entries) + np->data = i++; + /* Reverse traversal. */ + CIRCLEQ_FOREACH_REVERSE(np, &head, entries) + printf("%i\en", np->data); + /* Queue deletion. */ + n1 = CIRCLEQ_FIRST(&head); + while (n1 != (void *)&head) { + n2 = CIRCLEQ_NEXT(n1, entries); + free(n1); + n1 = n2; + } + CIRCLEQ_INIT(&head); + + exit(EXIT_SUCCESS); +} +.Ed .Sh CONFORMING TO Not in POSIX.1, POSIX.1-2001 or POSIX.1-2008. Present on the BSDs. |