CHAR_CLASS_MAX_LENGTH 1718 regex.cpp      #  define CHAR_CLASS_MAX_LENGTH CHARCLASS_NAME_MAX
CHAR_CLASS_MAX_LENGTH 1722 regex.cpp      #  define CHAR_CLASS_MAX_LENGTH 256
CHAR_CLASS_MAX_LENGTH 1727 regex.cpp      # define CHAR_CLASS_MAX_LENGTH  6 /* Namely, `xdigit'.  */