NAME

std::equal_to - std::equal_to

Synopsis

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

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

Specializations

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

std::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 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;
}