std::ranges:: not_equal_to

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C++
Utilities library
General utilities
Relational operators (deprecated in C++20)
Function objects
Function invocation
(C++17) (C++23)
Identity function object
(C++20)
Old binders and adaptors
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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).

Nested types

Nested type Definition
is_transparent unspecified

Member functions

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

std::ranges::not_equal_to:: operator()

template < class T, class U >
constexpr bool operator ( ) ( T && t, U && u ) const ;

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

This overload participates in overload resolution only if std:: equality_comparable_with < T, U > is satisfied.

Notes

Unlike std::not_equal_to , std::ranges::not_equal_to requires both == and != to be valid (via the equality_comparable_with constraint), and is entirely defined in terms of std::ranges::equal_to .

Example

This section is incomplete
Reason: no example

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 3530 C++20 syntactic checks were relaxed while comparing pointers only semantic requirements are relaxed

See also

function object implementing x ! = y
(class template)
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