Generic list manipulation function in C?

Question

What is a generic list manipulation function in C? (I saw this when I was going through some materials.)

What is the difference between this function and a function

Answer 1

I have been trying something different. This is another perspective how to board the problem

If we have the follow structure:

typedef struct token {
    int id;
    char *name;
    struct token *next;
} Token;

and we need to create a function that returns the tail of a linked list, but the function should be generic for any linked list, so:

void* tail(void* list, void* (*f)(void *)) {
    void *head = list;

    while(f(head) != NULL) {
        head = f(head);
    }

    return head;
}

Now will be necessary create a function responsible to do the bridge between the our custom struct to a generic usability in the tail function. In that way, we have:

void* nextToken(void *a) {
    Token *t = (Token *) t;
    return (void *) (a->next);
}

Finally we can simply use:

Token *listTokens;
(...)
Token *lastToken = tail(listTokens, nextToken);