NAME¶

std::totally_ordered,std::totally_ordered_with - std::totally_ordered,std::totally_ordered_with

Synopsis¶

Defined in header <concepts>
template< class T >

concept totally_ordered = (1) (since C++20)

std::equality_comparable<T> && __PartiallyOrderedWith<T,
T>;
template< class T, class U >

concept totally_ordered_with =
std::totally_ordered<T> &&
std::totally_ordered<U> &&
std::equality_comparable_with<T, U> && (2) (since C++20)
std::totally_ordered<
std::common_reference_t<
const std::remove_reference_t<T>&,
const std::remove_reference_t<U>&>> &&

__PartiallyOrderedWith<T, U>;
template< class T, class U >

concept __PartiallyOrderedWith =
requires(const std::remove_reference_t<T>& t,
const std::remove_reference_t<U>& u) {
{ t < u } -> boolean-testable;
{ t > u } -> boolean-testable;
{ t <= u } -> boolean-testable; (3) (exposition only*)
{ t >= u } -> boolean-testable;
{ u < t } -> boolean-testable;
{ u > t } -> boolean-testable;
{ u <= t } -> boolean-testable;
{ u >= t } -> boolean-testable;

};

1) The concept std::totally_ordered specifies that the comparison operators
==,!=,<,>,<=,>= on a type yield results consistent with a strict total order on the
type.
2) The concept std::totally_ordered_with specifies that the comparison operators
==,!=,<,>,<=,>= on (possibly mixed) T and U operands yield results consistent with a
strict total order. Comparing mixed operands yields results equivalent to comparing
the operands converted to their common type.
3) The exposition-only concept __PartiallyOrderedWith specifies that a value of type
T and a value of type U can be compared in a partial order with each other (in
either order) using <, >, <=, and >=, and the results of the comparisons are
consistent.

See also¶

three_way_comparable specifies that operator <=> produces consistent result on
three_way_comparable_with given types
(C++20) (concept)