[PATCH] queue.3: stailq: Complete example

[Michael Kerrisk (man-pages)]

On 10/17/20 12:16 PM, Alejandro Colomar wrote:
> Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>

Thanks, Alex. Patch applied.

Cheers,

Michael

> ---
>  man3/queue.3 | 117 ++++++++++++++++++++++++++++-----------------------
>  1 file changed, 64 insertions(+), 53 deletions(-)
> 
> diff --git a/man3/queue.3 b/man3/queue.3
> index 9cd6ff378..c48b4ba9f 100644
> --- a/man3/queue.3
> +++ b/man3/queue.3
> @@ -721,59 +721,9 @@ from the tail queue.
>  .\" .Fa head1
>  .\" and
>  .\" .Fa head2 .
> -.Ss Singly-linked tail queue example
> -.Bd -literal
> -STAILQ_HEAD(stailhead, entry) head =
> -    STAILQ_HEAD_INITIALIZER(head);
> -struct stailhead *headp;		/* Singly-linked tail queue head. */
> -struct entry {
> -	...
> -	STAILQ_ENTRY(entry) entries;	/* Tail queue. */
> -	...
> -} *n1, *n2, *n3, *np;
> -
> -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);
> -					/* Deletion. */
> -STAILQ_REMOVE(&head, n2, entry, entries);
> -free(n2);
> -					/* Deletion from the head. */
> -n3 = STAILQ_FIRST(&head);
> -STAILQ_REMOVE_HEAD(&head, entries);
> -free(n3);
> -					/* Forward traversal. */
> -STAILQ_FOREACH(np, &head, entries)
> -	np\-> ...
> -.\"					/* Safe forward traversal. */
> -.\"STAILQ_FOREACH_SAFE(np, &head, entries, np_temp) {
> -.\"	np\->do_stuff();
> -.\"	...
> -.\"	STAILQ_REMOVE(&head, np, entry, entries);
> -.\"	free(np);
> -.\"}
> -					/* TailQ Deletion. */
> -while (!STAILQ_EMPTY(&head)) {
> -	n1 = STAILQ_FIRST(&head);
> -	STAILQ_REMOVE_HEAD(&head, entries);
> -	free(n1);
> -}
> -					/* Faster TailQ Deletion. */
> -n1 = STAILQ_FIRST(&head);
> -while (n1 != NULL) {
> -	n2 = STAILQ_NEXT(n1, entries);
> -	free(n1);
> -	n1 = n2;
> -}
> -STAILQ_INIT(&head);
> -.Ed
> +.Pp
> +See the EXAMPLES section below for an example program
> +using a singly-linked tail queue.
>  .Ss Lists
>  A list is headed by a structure defined by the
>  .Nm LIST_HEAD
> @@ -1328,6 +1278,67 @@ main(void)
>      exit(EXIT_SUCCESS);
>  }
>  .Ed
> +.Ss Singly-linked tail queue example
> +.Bd -literal
> +#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 (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);
> +}
> +.Ed
>  .Ss List 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/