if ( PL_get_atom_chars(to, &s) ) { Sprintf("Hello \"%s\"\n", s); return TRUE; } else { term_t except; return ( (except=PL_new_term_ref()) && PL_unify_term(except, PL_FUNCTOR_CHARS, "type_error", 2, PL_CHARS, "atom", PL_TERM, to) && PL_raise_exception(except) ); } }