home | help 
std::experi...nges::Common(3)  C++ Standard Libary std::experi...nges::Common(3)

NAME
     std::experimental::ranges::Common - std::experimental::ranges::Common

Synopsis
	Defined in header <experimental/ranges/concepts>
	template< class T, class U >

	concept bool Common =
	    Same<ranges::common_type_t<T, U>, ranges::common_type_t<U, T>> &&
	    ConvertibleTo<T, ranges::common_type_t<T, U>> &&
	    ConvertibleTo<U, ranges::common_type_t<T, U>> &&
	    CommonReference<
		std::add_lvalue_reference_t<const			     T>,
     (ranges TS)
		std::add_lvalue_reference_t<const U>> &&
	    CommonReference<
		std::add_lvalue_reference_t<ranges::common_type_t<T, U>>,
		ranges::common_reference_t<
		    std::add_lvalue_reference_t<const T>,

		    std::add_lvalue_reference_t<const U>>>;

	The concept Common<T, U> specifies that two types T and U share a common
     type (as
	computed by ranges::common_type_t) to which both can be converted.

	Common<T, U> is satisfied only if, given expressions t and u  such  that
     decltype((t))
	is T and decltype((u)) is U,

	  *  ranges::common_type_t<T, U>(t) is equal to ranges::common_type_t<T,
     U>(t) if and
	    only if t is an equality-preserving expression; and
	  * ranges::common_type_t<T, U>(u) is equal to	ranges::common_type_t<T,
     U>(u) if and
	    only if u is an equality-preserving expression.

	In other words, the conversion to the common type must not alter the
	equality-preservation property of the original expression.

	Equality preservation

	An  expression	is  equality  preserving  if it results in equal outputs
     given equal
	inputs.

	  * The inputs to an expression consist of its operands.
	  * The outputs of an expression consist of its result and all	operands
     modified by
	    the expression (if any).

	Every  expression required to be equality preserving is further required
     to be
	stable: two evaluations of such an expression with the	same  input  ob-
     jects must have
	equal  outputs absent any explicit intervening modification of those in-
     put objects.

See also
	common_type	 determine the common type of a set of types
			 (class template)
	common_reference determine the common reference type of a set of types
			 (class template)
	CommonReference  specifies that two types share a common reference type
			 (concept)

http://cppreference.com 	   2024.06.10	   std::experi...nges::Common(3)
home | help