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;
These functions are described identically as those members of the same name in the ctype class template ([locale.ctype.members]).