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std::ranges::less(3)	       C++ Standard Libary	    std::ranges::less(3)

NAME
     std::ranges::less - std::ranges::less

Synopsis
	Defined in header <functional>
	struct less;			(since C++20)

	Function  object for performing comparisons. Deduces the parameter types
     of the
	function call operator from the arguments (but not the return type).

Member functions
	operator() checks if the first argument is less than the second
		   (public member function)

     std::ranges::less::operator()

	template< class T, class U >
	constexpr bool operator()( T&& t, U&& u ) const;

	Given the expression std::forward<T>(t) < std::forward<U>(u) as expr:

	  * If expr results in a call to built-in operator< comparing  pointers,
     given the
	    composite pointer type of t and u as P:

	  *  If the converted t precedes the converted u (both are of type P) in
     the
	    implementation-defined strict total  order	over  pointers,  returns
     true, otherwise
	    returns false.
	  *  If  the  conversion sequence from T to P or the conversion sequence
     from U to P is
	    not equality-preserving, the behavior is undefined.
	  * Otherwise:

	  * Returns the result of expr.
	  * If std::totally_ordered_with<T, U> is not modeled, the  behavior  is
     undefined.

	This overload participates in overload resolution only if
	std::totally_ordered_with<T, U> is satisfied.

	If there exists an expression expr1 of type T and an expression expr2 of
     U, such
	that  the comparison results of expr1 and expr2 violate strict total or-
     dering (rules
	are defined below), the behavior is undefined.

	The comparison results of expr1 and expr2 follow strict  total	ordering
     only if
	exactly one of the following expressions is true:

	  * std::ranges::less{}(expr1, expr2)
	  * std::ranges::less{}(expr2, expr1)
	  * std::ranges::equal_to{}(expr1, expr2)

Notes
	Unlike	std::less,  std::ranges::less requires all six comparison opera-
     tors <, <=, >,
	>=, == and != to be valid (via the totally_ordered_with constraint).

Example
	 This section is incomplete
	 Reason: no example

	Defect reports

	The following behavior-changing defect	reports  were  applied	retroac-
     tively to
	previously published C++ standards.

	   DR	 Applied to	  Behavior as published 	     Correct be-
     havior
	LWG  3530 C++20      syntactic checks were relaxed     only semantic re-
     quirements are
			    while comparing pointers	      relaxed

See also
	less function object implementing x < y
	     (class template)

Category:
	  * Todo no example

http://cppreference.com 	   2024.06.10		    std::ranges::less(3)
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