How can I use the doubly linked lists?

The GList object is defined as:

typedef struct _GList GList;

struct _GList
  gpointer data;
  GList *next;
  GList *prev;

To use the GList objects, simply:

GList   *list = NULL;
GList   *listrunner;
gint    array[] = { 1, 2, 3, 4, 5, 6 };
gint    pos;
gint    *value;

/* add data to the list */
for (pos=0;pos < sizeof array; pos++) {
  list = g_list_append(list, (gpointer)&array[pos]);

/* run through the list */
listrunner = g_list_first(list);
while (listrunner) {
  value = (gint *)listrunner->data;
  printf("%d\n", *value);
  listrunner = g_list_next(listrunner);

/* removing datas from the list */
listrunner = g_list_first(list);
list = g_list_remove_link(list, listrunner);
list = g_list_remove(list, &array[4]);

The same code is usable with singly linked lists (GSList objects) by replacing g_list_* functions with the relevant g_slist_* ones (g_slist_append, g_slist_remove, ...). Just remember that since you can't go backward in a singly linked list, there is no g_slist_first function - you'll need to keep a reference on the first node of the list.