std::strong_order

template< class T >
constexpr std::strong_ordering strong_order(const T& a, const T& b);

Compares two values using 3-way comparison and produces a result of type std::strong_ordering.

Specifically,

• First, if std::numeric_limits<T>::is_iec559 is true, performs the ISO/IEC/IEEE 60559 totalOrder comparison of floating-point values and returns that result as a value of type std::strong_ordering (note: this comparison can distinguish between the positive and negative zero and between the NaNs with different representations)
• Otherwise, if the expression a <=> b is well-formed and its result is convertible to std::strong_ordering, returns that result.
• Otherwise, if the expression a <=> b is well-formed, but its result is not convertible to std::strong_ordering, then the function is defined as deleted.
• Otherwise, if the expression a <=> b is ill-formed, but the expressions a == b and a < b are both well-formed and convertible to bool,
• if a == b is true, returns std::strong_ordering::equal
• otherwise, if a < b is true, returns std::strong_ordering::less
• otherwise, returns std::strong_ordering::greater
• Otherwise, the function is defined as deleted.

Parameters

Return value

A value of type std::strong_ordering, as described above.

Notes

Example

See also