Re: [PATCH] queue.3: list: Complete example

Michael Kerrisk (man-pages)
2020-10-15T18:50:22Z

On 10/15/20 1:29 PM, Alejandro Colomar wrote:
> Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>

Thanks, Alex. Patch applied.

Cheers,

Michael

> ---
> man3/queue.3 | 105 +++++++++++++++++++++++++++------------------------
> 1 file changed, 55 insertions(+), 50 deletions(-)
>
> diff --git a/man3/queue.3 b/man3/queue.3
> index fed8d126f..9cd6ff378 100644
> --- a/man3/queue.3
> +++ b/man3/queue.3
> @@ -921,56 +921,8 @@ from the list.
> .\" .Fa head1
> .\" and
> .\" .Fa head2 .
> -.Ss List example
> -.Bd -literal
> -LIST_HEAD(listhead, entry) head =
> - LIST_HEAD_INITIALIZER(head);
> -struct listhead *headp; /* List head. */
> -struct entry {
> - ...
> - LIST_ENTRY(entry) entries; /* List. */
> - ...
> -} *n1, *n2, *n3, *np, *np_temp;
> -
> -LIST_INIT(&head); /* Initialize the list. */
> -
> -n1 = malloc(sizeof(struct entry)); /* Insert at the head. */
> -LIST_INSERT_HEAD(&head, n1, entries);
> -
> -n2 = malloc(sizeof(struct entry)); /* Insert after. */
> -LIST_INSERT_AFTER(n1, n2, entries);
> -
> -n3 = malloc(sizeof(struct entry)); /* Insert before. */
> -LIST_INSERT_BEFORE(n2, n3, entries);
> -
> -LIST_REMOVE(n2, entries); /* Deletion. */
> -free(n2);
> - /* Forward traversal. */
> -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);
> - free(n1);
> -}
> -
> -n1 = LIST_FIRST(&head); /* Faster List Deletion. */
> -while (n1 != NULL) {
> - n2 = LIST_NEXT(n1, entries);
> - free(n1);
> - n1 = n2;
> -}
> -LIST_INIT(&head);
> -.Ed
> +.Pp
> +See the EXAMPLES section below for an example program using a linked list.
> .Ss Tail queues
> A tail queue is headed by a structure defined by the
> .Nm TAILQ_HEAD
> @@ -1376,6 +1328,59 @@ main(void)
> exit(EXIT_SUCCESS);
> }
> .Ed
> +.Ss List example
> +.Bd -literal
> +#include <stddef.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <sys/queue.h>
> +
> +struct entry {
> + int data;
> + LIST_ENTRY(entry) entries; /* List. */
> +};
> +
> +LIST_HEAD(listhead, entry);
> +
> +int
> +main(void)
> +{
> + struct entry *n1, *n2, *n3, *np;
> + struct listhead head; /* List head. */
> + int i;
> +
> + LIST_INIT(&head); /* Initialize the list. */
> +
> + n1 = malloc(sizeof(struct entry)); /* Insert at the head. */
> + LIST_INSERT_HEAD(&head, n1, entries);
> +
> + n2 = malloc(sizeof(struct entry)); /* Insert after. */
> + LIST_INSERT_AFTER(n1, n2, entries);
> +
> + n3 = malloc(sizeof(struct entry)); /* Insert before. */
> + LIST_INSERT_BEFORE(n2, n3, entries);
> +
> + i = 0; /* Forward traversal. */
> + LIST_FOREACH(np, &head, entries)
> + np->data = i++;
> +
> + LIST_REMOVE(n2, entries); /* Deletion. */
> + free(n2);
> + /* Forward traversal. */
> + LIST_FOREACH(np, &head, entries)
> + printf("%i\en", np->data);
> + /* List Deletion. */
> + n1 = LIST_FIRST(&head);
> + while (n1 != NULL) {
> + n2 = LIST_NEXT(n1, entries);
> + free(n1);
> + n1 = n2;
> + }
> + LIST_INIT(&head);
> +
> + exit(EXIT_SUCCESS);
> +}
> +.Ed
> .Ss Tail queue example
> .Bd -literal
> #include <stddef.h>
>

--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/