-// returns nonzero if c is a horizontal blank in the locale.
-int isblank( int c );
-
-// returns nonzero if c is a control character in the locale.
-int iscntrl( int c );
-
-// returns nonzero if c is a digit in the locale.
-int isdigit( int c );
-
-// returns nonzero if c is alphanumeric or a punctuation in the locale.
-int isgraph( int c );
-
-// returns nonzero if c is a lowercase alphabetic character in the locale.
-int islower( int c );
-
-// returns nonzero if c is a printable character ( isgraph() or isblank() ) in
-// the locale.
-int isprint( int c );
-
-// returns nonzero if c is a punctuation in the locale.
-int ispunct( int c );
-
-// returns nonzero if c is a whitespace in the locale.
-int isspace( int c );
-
-// returns nonzero if c is an uppercase alphabetical character in the locale.
-int isupper( int c );
-
-// returns nonzero if c is a hexedecimal digit in the locale.
-int isxdigit( int c );
-
-// returns lowercase equivalent for c in locale.