28 Localization library [localization]

28.4 Standard locale categories [locale.categories]

28.4.1 The ctype category [category.ctype]

28.4.1.3 ctype<char> specialization [facet.ctype.special]

28.4.1.3.4 Virtual functions [facet.ctype.char.virtuals]

char        do_toupper(char) const;
const char* do_toupper(char* low, const char* high) const;
char        do_tolower(char) const;
const char* do_tolower(char* low, const char* high) const;

virtual char        do_widen(char c) const;
virtual const char* do_widen(const char* low, const char* high, char* to) const;
virtual char        do_narrow(char c, char dfault) const;
virtual const char* do_narrow(const char* low, const char* high,
                              char dfault, char* to) const;