< cpp‎ | experimental‎ | ranges
Technical specifications
Filesystem library (filesystem TS)
Library fundamentals (library fundamentals TS)
Library fundamentals 2 (library fundamentals 2 TS)
Extensions for parallelism (parallelism TS)
Extensions for parallelism 2 (parallelism TS v2)
Extensions for concurrency (concurrency TS)
Concepts (concepts TS)
Ranges (ranges TS)
Special mathematical functions (special math TR)
General utilities library
Utility components
Function objects
Metaprogramming and type traits
Tagged pairs and tuples
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

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


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));.


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.


See also

function object implementing x <= y
(class template)