std::experimental::ranges::not_equal_to - cppreference.com (original) (raw)
| Defined in header <experimental/ranges/functional> | |||
|---|---|---|---|
| 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; | |
| template<> struct not_equal_to<void>; | (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.
Contents
[edit] Member types
| Member type | Definition |
|---|---|
| is_transparent (member only of not_equal_to specialization) | /* unspecified */ |
[edit] Member functions
| | 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 template) |
|---|---|---|
| template< class T, class U > requires EqualityComparableWith<T, U> | | /* std::declval() == std::declval() resolves to a built-in operator comparing pointers */ constexpr bool operator()(T&& t, U&& u) const; | (2) |
- Compares
xandy. Equivalent to return<>{}(x, y);.
[edit] 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.