std::greater_equal<void> - cppreference.com

From cppreference.com


`template<> class greater_equal<void>;`		(since C++14)

std::greater_equal<void> is a specialization of std::greater_equal with parameter and return type deduced.

Nested types

Member functions

tests if lhs compares greater or equal than rhs
(public member function)

std::greater_equal<void>::operator()

`template< class T, class U > constexpr auto operator()( T&& lhs, U&& rhs ) const -> decltype(std::forward<T>(lhs) >= std::forward<U>(rhs));`

Returns the result of std::forward<T>(lhs) >= std::forward<U>(rhs).

Parameters

lhs, rhs

values to compare

Return value

std::forward<T>(lhs) >= std::forward<U>(rhs).

If a built-in operator comparing pointers is called, the result is consistent with the implementation-defined strict total order over pointers.

Exceptions

May throw implementation-defined exceptions.

Example

#include <algorithm>
#include <functional>
#include <initializer_list>

constexpr bool strictly_not_negative(int lhs)
{
    return std::greater_equal<>()(lhs, 0);
}

int main()
{
    constexpr int low = 0, high = 8;
    std::greater_equal<> greater_equal{};
    static_assert(greater_equal(high, low));
    static_assert(greater_equal(low, low));

    static constexpr auto arr = {-1, 0, 1, 2, 3, 4};
    static_assert(!std::all_of(arr.begin(), arr.end(), strictly_not_negative));
    static_assert(std::all_of(arr.begin() + 1, arr.end(), strictly_not_negative));
}

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 2562	C++98	the pointer total order might be inconsistent	guaranteed to be consistent