bool is(mask m, charT c) const;
const charT* is(const charT* low, const charT* high,
mask* vec) const;
Returns: do_is(m,c) or do_is(low,high,vec)
const charT* scan_is(mask m,
const charT* low, const charT* high) const;
Returns: do_scan_is(m,low,high)
const charT* scan_not(mask m,
const charT* low, const charT* high) const;
Returns: do_scan_not(m,low,high)
charT toupper(charT) const;
const charT* toupper(charT* low, const charT* high) const;
Returns: do_toupper(c) or do_toupper(low,high)
charT tolower(charT c) const;
const charT* tolower(charT* low, const charT* high) const;
Returns: do_tolower(c) or do_tolower(low,high)
charT widen(char c) const;
const char* widen(const char* low, const char* high, charT* to) const;
Returns: do_widen(c) or do_widen(low,high,to)
char narrow(charT c, char dfault) const;
const charT* narrow(const charT* low, const charT*, char dfault,
char* to) const;
Returns: do_narrow(c,dfault) or do_narrow(low,high,dfault,to)