CODE EXAMPLE FOR CPP

why does the pointer value doesn;t change when I change it in funciton

int mystack_pop(int handle, void **obj)
{
    pStackMeta_t tmpStackList = gStackList;
    *obj = tmpStackList->stack->obj;
    tmpStackList->stack = tmpStackList->stack->next;
    tmpStackList->numelem -= 1;
    DBG_PRINTF("handle: %d, obj: %p
", handle, *obj);
    return 0;
}