std::ctype::is(3)

NAME
std::ctype::is - std::ctype::is

Synopsis
   Defined in header <locale>
   bool is( mask m, char c ) const; (1)
   const char* is( const char* low, const char* high, mask* vec ) const; (2)
   1) Checks if the character c is classified by the mask m according to the
   classification table returned by the member function table(). Effectively calculates
   table()[(unsigned char)c] & m.
   2) For every character in the character array [low, high), reads its full
   classification mask from the classification table returned by the member function
   table() (that is, evaluates table()[(unsigned char)*p] and stores it in the
   corresponding element of the array pointed to by vec.
   If (unsigned char)c >= std::ctype<char>::table_size, then an implementation-defined
   value is substituted instead of table()[(unsigned char)c], possibly different for
   different values of c.

Parameters
   c - character to classify
   m - mask to use for classifying a single character
   low - pointer to the first character in an array of characters to classify
   high - one past the end pointer for the array of characters to classify
   vec - pointer to the first element of the array of masks to fill

Return value
   1) true if c is classified by m in table(), false otherwise.
   2) high

Notes
   Unlike the primary template std::ctype, this specialization does not perform a
   virtual function call when classifying characters. To customize the behavior, a
   derived class may provide a non-default classification table to the base class
   constructor.

Example
    This section is incomplete
    Reason: no example
   Defect reports
   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.
     DR Applied to Behavior as published Correct behavior
                     overload (2) copied the values from vec into
   LWG 28 C++98 table(), corrected
                     which is the reverse of the intended behavior

See also
   do_is classifies a character or a character sequence
   [virtual] (virtual protected member function of std::ctype<CharT>)

Category:
     * Todo no example