std::experimental::ranges::not_equal_to
From cppreference.com
| Defined in header <experimental/ranges/functional>
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||
template< class T = void >
requires EqualityComparable<T> ||
Same<T, void> ||
/* == on two const T lvalues invokes a built-in operator comparing pointers */
struct not_equal_to;
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(ranges TS) | |
template<>
struct not_equal_to<void>;
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(ranges TS) | |
Function object for performing comparisons. The primary template invokes operator == on const lvalues of type T and negates the result. The specialization not_equal_to<void> deduces the parameter types of the function call operator from the arguments (but not the return type).
All specializations of not_equal_to are Semiregular.
Member types
| Member type | Definition |
is_transparent (member only of not_equal_to<void> specialization)
|
/* unspecified */ |
Member functions
operator() |
checks if the arguments are not equal (public member function) |
std::experimental::ranges::not_equal_to::operator()
constexpr bool operator()(const T& x, const T& y) const;
|
(1) | (member only of primary not_equal_to<T> template) |
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;
|
(2) | (member only of not_equal_to<void> specialization) |
1) Compares
x and y. Equivalent to return !ranges::equal_to<>{}(x, y);.2) Compares
t and u. Equivalent to return !ranges::equal_to<>{}(std::forward<T>(t), std::forward<U>(u));.
Notes
Unlike std::not_equal_to, ranges::not_equal_to requires both == and != to be valid (via the EqualityComparable and EqualityComparableWith constraints), and is entirely defined in terms of
ranges::equal_to. However, the implementation is free to use operator!= directly, because those concepts require the results of == and != to be consistent.
Example
| This section is incomplete Reason: no example |
See also
function object implementing x != y (class template) |