static void pqueue_destroy (struct pqueue *);
static bool pqueue_is_full (const struct pqueue *);
static bool pqueue_is_empty (const struct pqueue *);
static void pqueue_push (struct pqueue *, struct ccase *, casenumber);
static void pqueue_destroy (struct pqueue *);
static bool pqueue_is_full (const struct pqueue *);
static bool pqueue_is_empty (const struct pqueue *);
static void pqueue_push (struct pqueue *, struct ccase *, casenumber);