ctype(3C)                                                  ctype(3C)


       NAME
             ctype: isdigit, isxdigit, islower, isupper, isalpha, isalnum,
             isspace, iscntrl, ispunct, isprint, isgraph, isascii -
             character handling

       SYNOPSIS
             #include <ctype.h>
             int isalpha(int c);
             int isupper(int c);
             int islower(int c);
             int isdigit(int c);
             int isxdigit(int c);
             int isalnum(int c);
             int isspace(int c);
             int ispunct(int c);
             int isprint(int c);
             int isgraph(int c);
             int iscntrl(int c);
             int isascii(int c);

       DESCRIPTION
             These macros classify character-coded integer values.  Each is
             a predicate returning non-zero for true, zero for false.  The
             behavior of these macros, except for isdigit, isxdigit, and
             isascii, is affected by the current locale [see
             setlocale(3C)].  To modify the behavior, change the LC_TYPE
             category in setlocale, that is, setlocale (LC_CTYPE,
             newlocale).  In the C locale, or in a locale where character
             type information is not defined, characters are classified
             according to the rules of the US-ASCII 7-bit coded character
             set.

             The macro isascii is defined on all integer values; the rest
             are defined only where the argument is an int, the value of
             which is representable as an unsigned char, or EOF, which is
             defined by the stdio.h header file and represents end-of-file.

            isalpha
                    tests for any character for which isupper or islower is
                    true, or any character that is one of an
                    implementation-defined set of characters for which none
                    of iscntrl, isdigit, ispunct, or isspace is true.  In
                    the C locale, isalpha returns true only for the
                    characters for which isupper or islower is true.




                           Copyright 1994 Novell, Inc.               Page 1

      ctype(3C)                                                  ctype(3C)


           isupper
                   tests for any character that is an uppercase letter or
                   is one of an implementation-defined set of characters
                   for which none of iscntrl, isdigit, ispunct, isspace,
                   or islower is true.  In the C locale, isupper returns
                   true only for the characters defined as uppercase ASCII
                   characters.

           islower
                   tests for any character that is a lowercase letter or
                   is one of an implementation-defined set of characters
                   for which none of iscntrl, isdigit, ispunct, isspace,
                   or isupper is true.  In the C locale, islower returns
                   true only for the characters defined as lowercase ASCII
                   characters.

           isdigit
                   tests for any decimal-digit character.

           isxdigit
                   tests for any hexadecimal-digit character ([0-9], [A-F]
                   or [a-f]).

           isalnum
                   tests for any character for which isalpha or isdigit is
                   true (letter or digit).

           isspace
                   tests for any space, tab, carriage-return, newline,
                   vertical-tab, or form-feed (standard white-space
                   characters) or for one of an implementation-defined set
                   of characters for which isalnum is false.  In the C
                   locale, isspace returns true only for the standard
                   white-space characters.

           ispunct
                   tests for any printing character which is neither a
                   space nor a character for which isalnum is true.

           isprint
                   tests for any printing character, including space (``
                   '' ).

           isgraph
                   tests for any printing character, except space.



                          Copyright 1994 Novell, Inc.               Page 2

       ctype(3C)                                                  ctype(3C)


            iscntrl
                    tests for any ``control character'' as defined by the
                    character set.

            isascii
                    tests for any ASCII character, code between 0 and 0177
                    inclusive.

             All the character classification macros use a table lookup.

             Functions exist for all the above defined macros.  To get the
             function form, the macro name must be bypassed (for example,
             #undef isdigit).

          Files
             /usr/lib/locale/locale/LC_CTYPE

       REFERENCES
             ascii(5), chrtbl(1M), environ(5), setlocale(3C), stdio(3S),
             wchrtbl(1M), wctype(3C)

       NOTICES
             If the argument to any of the character handling macros is not
             in the domain of the function, the result is undefined.
























                           Copyright 1994 Novell, Inc.               Page 3