1#include <search.h>
 2#include "tsearch.h"
 3
 4static void walk(const struct node *r, void (*action)(const void *, VISIT, int), int d)
 5{
 6	if (!r)
 7		return;
 8	if (r->h == 1)
 9		action(r, leaf, d);
10	else {
11		action(r, preorder, d);
12		walk(r->a[0], action, d+1);
13		action(r, postorder, d);
14		walk(r->a[1], action, d+1);
15		action(r, endorder, d);
16	}
17}
18
19void twalk(const void *root, void (*action)(const void *, VISIT, int))
20{
21	walk(root, action, 0);
22}