[ratio.comparison] (original) (raw)

21 Metaprogramming library [meta]

21.4 Compile-time rational arithmetic [ratio]

21.4.5 Comparison of ratios [ratio.comparison]

template<class R1, class R2> struct ratio_equal : bool_constant<R1::num == R2::num && R1::den == R2::den> { };

template<class R1, class R2> struct ratio_not_equal : bool_constant<!ratio_equal_v<R1, R2>> { };

template<class R1, class R2> struct ratio_less : bool_constant<_see below_> { };

If R1​::​num × R2​::​den is less than R2​::​num × R1​::​den,ratio_less<R1, R2> shall be derived from bool_constant<true>; otherwise it shall be derived frombool_constant<false>.

Implementations may use other algorithms to compute this relationship to avoid overflow.

If overflow occurs, the program is ill-formed.

template<class R1, class R2> struct ratio_less_equal : bool_constant<!ratio_less_v<R2, R1>> { };

template<class R1, class R2> struct ratio_greater : bool_constant<ratio_less_v<R2, R1>> { };

template<class R1, class R2> struct ratio_greater_equal : bool_constant<!ratio_less_v<R1, R2>> { };