std::ranges::not_equal_to (3) - Linux Manuals

std::ranges::not_equal_to: std::ranges::not_equal_to


std::ranges::not_equal_to - std::ranges::not_equal_to


Defined in header <functional>
struct not_equal_to; (since C++20)

Function object for performing comparisons. Deduces the parameter types of the function call operator from the arguments (but not the return type).

Member types

Member type Definition
is_transparent /* unspecified */

Member functions

           checks if the arguments are not equal
operator() (public member function)


template< class T, class U >
requires EqualityComparableWith<T, U> ||
/* std::declval<T>() == std::declval<U>() resolves to
a built-in operator comparing pointers */
constexpr bool operator()(T&& t, U&& u) const;

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


Unlike std::not_equal_to, std::ranges::not_equal_to requires both == and != to be valid (via the EqualityComparableWith constraint), and is entirely defined in terms of std::ranges::equal_to. However, the implementation is free to use operator!= directly, because those concepts require the results of == and != to be consistent.


 This section is incomplete
 Reason: no example

See also

             function object implementing x != y
not_equal_to (class template)