__twalk (vroot, action) const void *vroot; __action_fn_t action;
__twalk (const void *vroot, __action_fn_t action)
__twalk (vroot, action)     const void *vroot;     __action_fn_t action;{  const node *root = (node *) vroot;  if (root != NULL && action != NULL)    trecurse (root, action, 0);}