Thread: using free with a casted pointer..

hello everybody! I have one doubt.. Can free() be used with a casted pointer? My situation:
I have these 2 structs which implement a doubly-linked list:

Code:

struct list_head{
	struct list_head *next;
	struct list_head *prev;
};
typedef struct list_head ListHead;
typedef ListHead *ListHeadPtr;

struct node{
	struct list_head lh;
	int pid;
};
typedef struct node Node;
typedef Node *NodePtr;

and I have to implement my function to delete from list:

Code:

void delete_node (ListHeadPtr head, ListHeadPtr node)
{
	(node->prev)->next=node->next;
	(node->next)->prev=node->prev;
	free((NodePtr)node);
}

is this ok? otherwise i could write the least general:

Code:

void delete_node (ListHeadPtr head, NodePtr node)
{
	((node->lh).prev)->next = (node->lh).next;
	((node->lh).next)->prev = (node->lh).prev;
	free(node);
}

which one is better in your opinion?thanks!

For C, I actually don't think it matters in the least, seeing as free takes a void* pointer.
Btw, avoid typedef-ing pointer types. They get confusing to read.

As Elysia says, as long as what you pass in is a pointer of some type and has the same value as you got out of malloc, it doesn't matter what type the pointer is.

It is, again, as Elysia says, a different story in C++, when using delete, where a destructor gets involved in the deleting process. But in C, any old pointer will do fine. malloc/free uses some extra data that is outside of the data you actually used to indicate what the original size you allocated was.

The danger would be if you make a mistake and free something that wasn't allocated (or a pointer in the middle of a previously allocated block) - that will lead to all manner of problems.

--
Mats