explicit ctype(const mask* tbl = nullptr, bool del = false, size_t refs = 0);
bool is(mask m, char c) const;
const char* is(const char* low, const char* high, mask* vec) const;
const char* scan_is(mask m, const char* low, const char* high) const;
const char* scan_not(mask m, const char* low, const char* high) const;
char toupper(char c) const;
const char* toupper(char* low, const char* high) const;
char tolower(char c) const;
const char* tolower(char* low, const char* high) const;
char widen(char c) const;
const char* widen(const char* low, const char* high, char* to) const;
char narrow(char c, char dfault) const;
const char* narrow(const char* low, const char* high, char dfault, char* to) const;
const mask* table() const noexcept;