ctype(3C)           (C Programming Language Utilities)            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 isascii, is affected by the current locale
         [see setlocale(3C)].  To modify the behavior, change the LCTYPE
         category in setlocale(3C), that is, setlocale (LCCTYPE, 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.

         isupper        tests for any character that is an upper-case 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 upper-case ASCII characters.





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   ctype(3C)           (C Programming Language Utilities)            ctype(3C)


         islower        tests for any character that is a lower-case 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
                        lower-case 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.

         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 and the conversion functions
         and macros use a table lookup.

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

   FILES
         /usr/lib/locale/locale/LCCTYPE

   SEE ALSO
         chrtbl(1M), setlocale(3C), stdio(3S), ascii(5), environ(5).





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   ctype(3C)           (C Programming Language Utilities)            ctype(3C)


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


















































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