std::ratio_not_equal
Min standard notice:
Header: <ratio>
If the ratios R1 and R2 are not equal, provides the member constant value equal true. Otherwise, value is false.
# Declarations
template< class R1, class R2 >
struct ratio_not_equal : std::integral_constant<bool, /* see below */> { };
(since C++11)
# Example
#include <ratio>
static_assert(std::ratio_not_equal_v<std::ratio<6, 9>, std::ratio<9, 6>>, "6/9 != 9/6");
int main() {}