NAME¶

std::not_equal_to - std::not_equal_to

Synopsis¶

Defined in header <functional>
template< class T > (until C++14)
struct not_equal_to;
template< class T = void > (since C++14)
struct not_equal_to;

Function object for performing comparisons. Unless specialised, invokes operator!=
on type T.

Specializations¶

The standard library provides a specialization of std::not_equal_to
when T is not specified, which leaves the parameter types and return
type to be deduced.
(since C++14)
not_equal_to<void> function object implementing x != y deducing
(C++14) argument and return types
(class template specialization)

Member types¶

Type Definition
result_type (deprecated in C++17)(removed in C++20) bool
first_argument_type (deprecated in C++17)(removed in C++20) T
second_argument_type (deprecated in C++17)(removed in C++20) T

These member types are obtained via publicly inheriting (until C++11)
std::binary_function<T, T, bool>.

Member functions¶

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

std::not_equal_to::operator()

bool operator()( const T& lhs, const T& rhs ) const; (until C++14)
constexpr bool operator()( const T& lhs, const T& rhs ) const; (since C++14)

Checks whether lhs is not equal to rhs.

Parameters¶

lhs, rhs - values to compare

Return value¶

true if lhs != rhs, false otherwise.

Exceptions¶

May throw implementation-defined exceptions.

Possible implementation¶

constexpr bool operator()(const T &lhs, const T &rhs) const
{
return lhs != rhs;
}

See also¶

equal determines if two sets of elements are the same
(function template)
less function object implementing x < y
(class template)
ranges::not_equal_to function object implementing x != y
(C++20) (class)