C Template List GDB printer: V2 C

#include <stdlib.h>
#include <stddef.h>
#include <assert.h>

typedef struct listNode {
    void                 *data;         /* node's data                       */
    struct listNode      *next;         /* next node in list                 */
} listNode;

typedef void (*ListDelF)(void*);

typedef struct xlist {
    struct listNode      *head;         /* head of the list                  */
    struct listNode     **tail;         /* addr of last node's 'next' ptr    */
    struct listIterator  *iNext;        /* iterator chain for list_destroy() */
    ListDelF              fDel;         /* function to delete node data      */
    int                   count;        /* number of nodes in list           */
    const char           *dataType;     /* string literal: type of node data */
} xlist;

typedef struct xlist * List;


listNode *createNode(void* data) {
    listNode *node = (listNode*)malloc(sizeof(listNode));
    node->data = data;
    node->next = NULL;
    return node;
}
xlist *createList(const char *dataType) {
    xlist *list = (xlist*)malloc(sizeof(xlist));
    list->fDel = &free;
    list->iNext = NULL;
    list->count = 0;
    list->head = createNode(NULL);
    list->tail = &list->head->next;
    list->dataType = dataType;
    return list;
}
void addNodeToList(xlist *list, listNode* node) {
    assert(!node->next);
    *list->tail = node;
    list->tail = &node->next;
    list->count++;
}
int *createInt(int x) {
    int *ptr = (int*)malloc(sizeof(int));
    *ptr = x;
    return ptr;
}

int main() {
    int N = 10;
    List mylist = createList("int");
    for (int i = 0; i < N; i++)
        addNodeToList(mylist, createNode(createInt(i * 71 % 100)));

    return 0;
}