std::equal_to, not_equal_to, less, greater, less_equal, greater_equal(std::experimental::propagate_const)

 

C++

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Feature test macros (C++20)

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Technical specifications

Symbols index

External libraries

 

Technical specifications

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals TS v2)

Library fundamentals 3 (library fundamentals TS v3)

Extensions for parallelism (parallelism TS)

Extensions for parallelism 2 (parallelism TS v2)

Extensions for concurrency (concurrency TS)

Extensions for concurrency 2 (concurrency TS v2)

Concepts (concepts TS)

Ranges (ranges TS)

Reflection (reflection TS)

Mathematical special functions (special functions TR)

 

Library fundamentals v2

experimental::propagate_const

experimental::not_fn

experimental::observer_ptr

experimental::make_array

experimental::to_array

experimental::ostream_joiner

experimental::gcd

experimental::lcm

experimental::source_location

experimental::randint

detection idiom

uniform container erasure

logical operator type traits

 

std::experimental::propagate_const

Member functions

propagate_const::propagate_const

propagate_const::operator=

propagate_const::swap

Observers

propagate_const::get

propagate_const::operator bool

propagate_const::operator*propagate_const::operator->

propagate_const::operator element_type*propagate_const::operator const element_type*

Non-member functions

operator==operator!=operator<operator>operator<=operator>operator>=

swap

get_underlying

Helper classes

std::hash

std::equal_tostd::not_equal_tostd::lessstd::greaterstd::less_equalstd::greater_equal

 

Defined in header <experimental/propagate_const>
template<class T> struct equal_to<std::experimental::propagate_const<T>>;		(library fundamentals TS v2)
template<class T> struct not_equal_to<std::experimental::propagate_const<T>>;		(library fundamentals TS v2)
template<class T> struct less<std::experimental::propagate_const<T>>;		(library fundamentals TS v2)
template<class T> struct greater<std::experimental::propagate_const<T>>;		(library fundamentals TS v2)
template<class T> struct less_equal<std::experimental::propagate_const<T>>;		(library fundamentals TS v2)
template<class T> struct greater_equal<std::experimental::propagate_const<T>>;		(library fundamentals TS v2)

The standard comparison function objects are partially specialized for std::experimental::propagate_const<T>.

Let p.t_ denote the pointer-like object wrapped by a std::experimental::propagate_const<T> p, then given objects p and q of type std::experimental::propagate_const<T>, the following shall hold:

• std::equal_to<std::experimental::propagate_const<T>>()(p, q) == std::equal_to<T>()(p.t_, q.t_)
• std::not_equal_to<std::experimental::propagate_const<T>>()(p, q) == std::not_equal_to<T>()(p.t_, q.t_)
• std::less<std::experimental::propagate_const<T>>()(p, q) == std::less<T>()(p.t_, q.t_)
• std::greater<std::experimental::propagate_const<T>>()(p, q) == std::greater<T>()(p.t_, q.t_)
• std::less_equal<std::experimental::propagate_const<T>>()(p, q) == std::less_equal<T>()(p.t_, q.t_)
• std::greater_equal<std::experimental::propagate_const<T>>()(p, q) == std::greater_equal<T>()(p.t_, q.t_)

Notes

These specializations ensure that when T is a pointer type, specializations of these class templates for std::experimental::propagate_const<T> yield a total order, even if the corresponding built-in operators do not.

See also

equal_to	function object implementing x == y (class template)
not_equal_to	function object implementing x != y (class template)
less	function object implementing x < y (class template)
greater	function object implementing x > y (class template)
less_equal	function object implementing x <= y (class template)
greater_equal	function object implementing x >= y (class template)