topo_node_walk_init
if ((wp = topo_node_walk_init(thp, mod, node, (int (*)())cb_f, pdata,
if ((wp = topo_node_walk_init(thp, NULL, tp->tt_root,
extern topo_walk_t *topo_node_walk_init(topo_hdl_t *, topo_mod_t *, tnode_t *,