Free a pointer from an external function

Question

I wrote a program that uses a stack ADT.
The main creates a new stack while giving 3 functions to use from the user:

Stack my_stack = sCreate (copy_int, free_int, print_int);

when I call to a 'peek' function:

printf ("Peek: |%d|\n\n", *(int*)sPeek(my_stack));

I have a memory leak.

the peek function looks like this:

Element sPeek (Stack stack){
if ((NULL == stack) || (0 >= stack->used_places))
    return NULL;

Element returnElement = stack->copy_function(stack->stack_array[stack->used_places-1]);
if (NULL == returnElement){
    free (returnElement);
    return NULL;
}   
return returnElement;

It's caused probably by the copy_function called there, which is the copy_int that was given by the user:

Element copy_int (Element element){
int *new_int = (int*) malloc(sizeof(int*));
*new_int = *(int*)element;
if (NULL != new_int)
    return new_int;
else
    return NULL;

How do I release the pointer (malloc) from copy_int?

Answer 1

Element e = sPeek(my_stack);
if (e) {
    printf ("Peek: |%d|\n\n", *(int*)e);
}
free(e);

Seems a bit obvious so not sure if that's what you meant.