Availability:C-language interface function
bool PL_get_name_arity(term_t
+t, atom_t *name, size_t *arity)If t is compound or an atom, the functor name will be
assigned over name and the arity over arity
(either or both may be NULL). See also PL_get_compound_name_arity(), PL_get_functor()
and PL_is_functor().