In the following code, I'm using malloc for adding a new item to a hashmap. I thought I've checked all the boxes for properly using malloc, but valgrind says I've got a memory leak on them. Can someone point me to where I've gone wrong?
#include <stdlib.h>
#include <string.h>
typedef struct node
{
char content[46];
struct node* next;
}
node;
typedef node* hashmap_t;
int main (int argc, char *argv[]) {
hashmap_t hashtable[1000];
node *n = malloc(sizeof(node));
if(n == NULL) return 0;
hashmap_t new_node = n;
new_node->next = malloc(sizeof(node));
if(new_node->next == NULL) {
free(n);
return 0;
}
strncpy(new_node->content, "hello", 45);
hashtable[10] = new_node;
for(int y=0; y < 1000; y++) {
if(hashtable[y] != NULL) {
free(hashtable[y]->next);
free(hashtable[y]);
}
}
return 1;
}
For the line
if(hashtable[y] != NULL)
You do not initialise hashtable
to any value and it is also declared as a local variable. The initial value shall be some garbage value. So you cannot assume that if hashtable[y]
shall be NULL
for all 1000 elements of the array.
You can initialize the structure to zero while declaring e.g.
hashmap_t hashtable[1000] = {0};
or you can declare it as a global variable.