CODEWITHSUNDEEP
cmemorylinked-listmalloc
Tom
Tom

Reputation: 3

C LinkedList - how to free memory?

I want to write a small function that shall free the memory of a linked list. The nodes have been created with malloc.

A typical function for this is:

void freeList(struct node* head)
{
struct node* tmp;

while (head != NULL)
{
   tmp = head;
   head = head->next;
   free(tmp);
}

}

My problem is that I receive the following errors and i dont know how to fix them:

warning: assignment from incompatible pointer type tmp = l;

error: 'linked_list' has no member named 'next' l = l -> next;

The declarations are given:

struct node_s {
struct node_s *next;
char msg[MAX_MSG_LEN];
unsigned int time;
};

typedef struct node_s node;

struct linked_list_s {
node *head;
};

typedef struct linked_list_s linked_list;

void list_free(linked_list *l) {
   struct node *tmp;
   while (l !=NULL) {
     tmp = l;
     l = l -> next;
     free(tmp);
  }
}

Upvotes: 0

Views: 1111

Answers (1)

Iharob Al Asimi
Iharob Al Asimi

Reputation: 53046

You need to assign l->head to the tmp variable inside list_free() function and have another variable to store the next node while you free() tmp, like this

void list_free(linked_list *l) 
 {
   struct node *tmp;
   struct node *next;
   if (l == NULL)
      return;
   tmp = l->head;
   while (tmp != NULL) 
    {
      next = tmp->next;          
      free(tmp);
      tmp = next;
    }
 }

Upvotes: 1

Related Questions