# std::experimental::ranges::less_equal

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< cpp‎ | experimental‎ | ranges

Defined in header `<experimental/ranges/functional>` |  |
template< class T = void > requires StrictTotallyOrdered<T> || Same<T, void> || /* < on two const T lvalues invokes a built-in operator comparing pointers */ struct less_equal; |  | (ranges TS)
template<> struct less_equal<void>; |  | (ranges TS)

Function object for performing comparisons. The primary template invokes operator< on const lvalues of type `T` with the argument order inverted and then negates the result. The specialization `less_equal<void>` deduces the parameter types of the function call operator from the arguments (but not the return type).

All specializations of `less_equal` are `Semiregular`.

### Member types

Member type | Definition
`is_transparent` (member only of `less_equal<void>` specialization) | /* unspecified */

### Member functions

operator() | checks if the first argument is less than or equal to the second (public member function)

## std::experimental::ranges::less_equal::operator()

constexpr bool operator()(const T& x, const T& y) const; | (1) | (member only of primary `less_equal<T>` template)
template< class T, class U > requires StrictTotallyOrderedWith<T, U> || /* std::declval<T>() < std::declval<U>() resolves to a built-in operator comparing pointers */ constexpr bool operator()(T&& t, U&& u) const; | (2) | (member only of `less_equal<void>` specialization)

1) Compares `x` and `y`. Equivalent to return !ranges::less<>{}(y, x);.
2) Compares `t` and `u`. Equivalent to return !ranges::less<>{}(std::forward<U>(u), std::forward<T>(t));.

### Notes

Unlike std::less_equal, `ranges::less_equal` requires all six comparison operators `<`, `<=`, `>`, `>=`, `==` and `!=` to be valid (via the `StrictTotallyOrdered` and `StrictTotallyOrderedWith` constraints) and is entirely defined in terms of ranges::less. However, the implementation is free to use operator<= directly, because those concepts require the results of the comparison operators to be consistent.

### Example

| This section is incomplete Reason: no example

### See also

less_equal | function object implementing x <= y (class template)

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