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std::less_equal<void>

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less_equal<>
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Defined in header <functional>
template<>
class less_equal<void>;
(since C++14)

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

Contents

[edit] Nested types

Nested type Definition
is_transparent unspecified

[edit] Member functions

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

std::less_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.

[edit] Exceptions

May throw implementation-defined exceptions.

[edit] Example

#include <algorithm>
#include <functional>
#include <initializer_list>
 
constexpr bool strictly_not_positive(int lhs)
{
    return std::less_equal<>()(lhs, 0);
}
 
int main()
{
    constexpr int low = 0, high = 8;
    std::less_equal<> less_equal{};
    static_assert(less_equal(low, high));
    static_assert(less_equal(low, low));
 
    static constexpr auto arr = {1, 0, -1, -2, -3, -4};
    static_assert(!std::all_of(arr.begin(), arr.end(), strictly_not_positive));
    static_assert(std::all_of(arr.begin() + 1, arr.end(), strictly_not_positive));
}

[edit] 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