cpp/locale/ctype/is

@1,2@ public member function, calls the protected virtual member function of the most derived class. @3@ Checks if the character is classified by the mask @4@ For every character in the character array, identifies the complete classification mask (e.g. for the digit  in the default locale), and stores the masks in the corresponding elements of the array pointed to by

Return value
@1,3@ if  is classified by @2,4@