[sample] linked list (C language)

llist.h

/*
    llist.h
*/
#ifndef INCLUDED_LLIST_H
#define INCLUDED_LLIST_H

#define llist_init(l_)  ((l_)->next = (l_)->prev = (l_))

#define llist_next(l_)  ((l_)->next)
#define llist_prev(l_)  ((l_)->prev)

#define llist_ins_next(l_, x_)  (\
            (x_)->next       = (l_)->next   ,\
            (x_)->prev       = (l_)         ,\
            (l_)->next->prev = (x_)         ,\
            (l_)->next       = (x_)         )

#define llist_ins_prev(l_, x_)  (\
            (x_)->prev       = (l_)->prev   ,\
            (x_)->next       = (l_)         ,\
            (l_)->prev->next = (x_)         ,\
            (l_)->prev       = (x_)         )

#define llist_del(l_)               (\
            (l_)->prev->next = (l_)->next   ,\
            (l_)->next->prev = (l_)->prev   )

#endif /* !INCLUDED_LLIST_H */

sample-llist.c

/*
    sample-llist.c

    to build:
      $ make sample-list
*/
#include <stdio.h>  /* printf()     */
#include <stdlib.h> /* EXIT_SUCCESS */

#include "llist.h"

typedef struct station_t {
    char *name;

    struct station_t *next;     /* 'next' must be defined */
    struct station_t *prev;     /* 'prev' must be defined */
} STATION_t;

int main(void)
{
    STATION_t head;     /* head of list */

    STATION_t tokyo         = {"Tokyo"      },  *s1 = &tokyo,
              nagoya        = {"Nagoya"     },  *s2 = &nagoya,
              shin_ohsaka   = {"Shin-Ohsaka"},  *s3 = &shin_ohsaka;

    STATION_t *st;


    llist_init(&head);          /* (head)                                       */
    llist_ins_next(&head, s1);  /* (head) - [Tokyo]                             */
    llist_ins_next(s1,    s2);  /* (head) - [Tokyo] - [Nagoya]                  */
    llist_ins_next(s2,    s3);  /* (head) - [Tokyo] - [Nagoya] - [Shin-Ohsaka]  */


    for (st = llist_next(&head); st != &head; st = llist_next(st)) {
        printf("-> %s ", st->name);
    }
    printf("\n");

    return EXIT_SUCCESS;
}