From: Alejandro Colomar <colomar.6.4.3@gmail.com>
Date: Tue, 13 Oct 2020 14:55:49 +0000 (+0200)
Subject: queue.3: circleq: Complete example
X-Git-Tag: man-pages-5.09~165
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=46b0a9d69cc031e0cb64f0f7ba6fe7eb2aba3a57;p=thirdparty%2Fman-pages.git

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>
---

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.