std::experimental::ranges::less_equal

C++

Language

Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

Technical specifications

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals 2 TS)

Extensions for parallelism (parallelism TS)

Extensions for parallelism 2 (parallelism TS v2)

Extensions for concurrency (concurrency TS)

Concepts (concepts TS)

Ranges (ranges TS)

Special mathematical functions (special math TR)

Ranges

Concepts

General utilities

Iterators

Ranges

Algorithms

General utilities library

Utility components
swap	exchange
Function objects
invoke identity	equal_to not_equal_to	greater less	greater_equal less_equal
Metaprogramming and type traits
is_swappable_withis_swappable	is_nothrow_swappable_withis_nothrow_swappable	common_reference common_type
Tagged pairs and tuples
TagSpecifier TaggedType	tagged tag specifiers	tagged_pair make_tagged_pair	tagged_tuple make_tagged_tuple

Defined in header <experimental/ranges/functional>
template< class T = void > requires StrictTotallyOrdered<T> || Same<T, void> || /* < on two const T lvalues invokes a built-in operator comparing pointers */ struct less_equal;		(ranges TS)
template <> struct less_equal<void>;		(ranges TS)

Function object for performing comparisons. The primary template invokes operator< on const lvalues of type T with the argument order inverted and then negates the result. The specialization less_equal<void> deduces the parameter types of the function call operator from the arguments (but not the return type).

All specializations of less_equal are Semiregular.

Member types

Member type	Definition
is_transparent (member only of less_equal<void> specialization)	/* unspecified */

Member functions

operator()

checks if the first argument is less than or equal to the second (public member function)

std::experimental::ranges::less_equal::operator()

constexpr bool operator()(const T& x, const T& y) const;	(1)	(member only of primary less_equal<T> template)
template< class T, class U > requires StrictTotallyOrderedWith<T, U> || /* std::declval<T>() < std::declval<U>() resolves to a built-in operator comparing pointers */ constexpr bool operator()(T&& t, U&& u) const;	(2)	(member only of less_equal<void> specialization)

1) Compares x and y. Equivalent to return !ranges::less<>{}(y, x);

2) Compares t and u. Equivalent to return !ranges::less<>{}(std::forward<U>(u), std::forward<T>(t));.

Notes

Unlike std::less_equal, ranges::less_equal requires all six comparison operators <, <=, >, >=, == and != to be valid (via the StrictTotallyOrdered and StrictTotallyOrderedWith constraints) and is entirely defined in terms of ranges::less. However, the implementation is free to use operator<= directly, because those concepts require the results of the comparison operators to be consistent.

See also

less_equal

function object implementing x <= y (class template)