“If an implementation supports a mode with alternative interpretations for
Wide_Character, the set of graphic characters of
Charactershould nevertheless remain a proper subset of the set of graphic characters of
Wide_Character. Any character set ‘localizations’ should be reflected in the results of the subprograms defined in the language-defined package
Characters.Handling(see A.3) available in such a mode. In a mode with an alternative interpretation of
Character, the implementation should also support a corresponding change in what is a legal
Not all wide character modes follow this advice, in particular the JIS and IEC modes reflect standard usage in Japan, and in these encoding, the upper half of the Latin-1 set is not part of the wide-character subset, since the most significant bit is used for wide character encoding. However, this only applies to the external forms. Internally there is no such restriction.