std::indirect_strict_weak_order
Min standard notice:
Header: <iterator>
The concept indirect_strict_weak_order specifies requirements for algorithms that call strict weak orders as their arguments. The key difference between this concept and std::strict_weak_order is that it is applied to the types that I1 and I2 references, rather than I1 and I2 themselves.
# Declarations
template< class F, class I1, class I2 = I1 >
concept indirect_strict_weak_order =
std::indirectly_readable<I1> &&
std::indirectly_readable<I2> &&
std::copy_constructible<F> &&
std::strict_weak_order
<F&, /*indirect-value-t*/<I1>, /*indirect-value-t*/<I2>> &&
std::strict_weak_order
<F&, /*indirect-value-t*/<I1>, std::iter_reference_t<I2>> &&
std::strict_weak_order
<F&, std::iter_reference_t<I1>, /*indirect-value-t*/<I2>> &&
std::strict_weak_order
<F&, std::iter_reference_t<I1>, std::iter_reference_t<I2>>;
(since C++20)
# Defect reports
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| P2609R3 | C++20 | some requirements were defined in terms ofstd::iter_value_t& which mishandled projectionsresulting in incompatibility with strict weak order F& | defined in terms of/indirect-value-t/ tocorrectly handle such projections |
| P2997R1 | C++20 | indirect_strict_weak_order required F& to satisfystrict_weak_order with std::iter_common_reference_t | does not require |