Link List with hack remove function in C by Linus Torvalds. He tells me what the pointer is.

linus_ll.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

struct link_list
{
	int key;
	struct link_list	*next;
};

struct link_list *insert_ll(struct link_list *head, int key)
{
	struct link_list *ptr = (struct link_list *)malloc(sizeof(struct link_list));
	ptr -> key = key;
	ptr -> next = head;
	return ptr;
}

void remove_ll(struct link_list **head, int key)
{
	struct link_list **cur;
	for (cur = head; *cur; )
	{
		struct link_list *entry = *cur;
		if (entry -> key == key)
		{
			*cur = entry -> next;
			free(entry);
		}
		else
			cur = &entry -> next;
		
	}
}

void print_ll(struct link_list *head)
{
	struct link_list *ptr;
	for (ptr = head; ptr; ptr = ptr -> next)
		printf("%d ", ptr -> key);
	printf("\n");
}

struct link_list	*HEAD;

int main()
{
	HEAD = NULL;
	HEAD = insert_ll(HEAD, 1);
	HEAD = insert_ll(HEAD, 3);
	HEAD = insert_ll(HEAD, 2);
	HEAD = insert_ll(HEAD, 4);
	print_ll(HEAD);
	remove_ll(&HEAD, 3);
	print_ll(HEAD);
	remove_ll(&HEAD, 4);
	print_ll(HEAD);
	return 0;
}