mp_units::named_constant<Symbol, U, RSU>¶ Specialization for a measured constant declaring its relative standard uncertainty Synopsis¶ Declared in <mp-units/framework/unit_definitions.h> template<symbol_text Symbol, Unit auto U, typename M, relative_standard_uncertainty<M> RSU> requires(!Symbol.empty()) && detail::magnitude_is_positive<M{}> struct named_constant<Symbol, U, RSU> : ::_base_type_ Description¶ The same as the above but additionally stores the relative standard uncertainty of a constant that is measured rather than exact by definition. The value transcribes the entry published in the source metrology table (e.g., CODATA). Base Classes¶ NameDescription ::_base_type_ Type Aliases¶ Name _base_type_ Static Data Members¶ NameDescription _relative_standard_uncertainty_ _symbol_ Unique constant identifier Template Parameters¶ NameDescription Symbola short text representation of the constant Unita unit that we use to define a constant RSUthe relative standard uncertainty of the measured value