Thread: Why did the value of my void pointer change?

I have a the following in a header file.

Code:

struct SortedList
{
	void * data;		 
	struct SortedList * next; 		
	struct SortedList * previous;
	int (*compareFunc)(void *, void *);
	void (*destructor)(void *);
};
typedef struct SortedList* SortedListPtr;

SortedListPtr SLCreate(CompareFuncT cf, DestructFuncT df);

-------------------------------------------------------------------
In a .c file, I implemented the SLCreate function.

Code:

SortedListPtr SLCreate(CompareFuncT cf, DestructFuncT df)
{
	struct SortedList item; 		
	item.data = NULL;				
	item.next = (struct SortedList *) malloc(sizeof(struct SortedList));
	item.previous = (struct SortedList *) malloc(sizeof(struct SortedList));
	item.compareFunc = cf;
	item.destructor = df;
	SortedListPtr ptr = (struct SortedList *) malloc(sizeof(struct SortedList));	
	ptr = &item;
	return ptr;
};

In main.c, I try to do the following:

Code:

SortedListPtr list = SLCreate(&compareInts, &destroy);

...... A bunch other code that does not alter list or it's contents at all. 



struct SortedList item = (*list);
void * data = item.data;

if (data != NULL)	
{
	printf("Why did data become not null???\n");
}

-------------------------------------------------------------------
So my problem is how come my variable data became not null anymore when I haven't altered it at all and how can I fix this??