CTYPE(3C-SVR4)      RISC/os Reference Manual       CTYPE(3C-SVR4)



NAME
     ctype: isdigit, isxdigit, islower, isupper, isalpha, isal-
          num, 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 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 charac-
                    ters 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.




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CTYPE(3C-SVR4)      RISC/os Reference Manual       CTYPE(3C-SVR4)



     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.

     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 i 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.





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CTYPE(3C-SVR4)      RISC/os Reference Manual       CTYPE(3C-SVR4)



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

FILES
     /<systype>/usr/lib/locale/<locale>/LC_CTYPE

SEE ALSO
     setlocale(3C-SVR4), stdio(3S-SVR4), wctype(3W-SVR4),
     ascii(5-SVR4), environ(5-SVR4).
     chrtbl(1M) in the System Administrator's Reference Manual.

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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