stacks_ulwp_t
stacks_ulwp_t *sulwp = mdb_alloc(sizeof (stacks_ulwp_t), UM_SLEEP);
const stacks_ulwp_t *lhs = l;
const stacks_ulwp_t *rhs = r;
stacks_ulwp_t *sulwp, cmp;
avl_create(tree, stacks_ulwp_compare, sizeof (stacks_ulwp_t),
offsetof(stacks_ulwp_t, sulwp_node));
stacks_ulwp_t *sulwp;
mdb_free(sulwp, sizeof (stacks_ulwp_t));