ctype(3C)                                               ctype(3C)



NAME
     isalpha, isupper, islower, isdigit, isxdigit, isalnum,
     isspace,  ispunct,  isprint,  isgraph,  iscntrl,  isascii  -
     classify characters

SYNOPSIS
     #include <ctype.h>

     int isalpha(c)
     int c;

     ...

DESCRIPTION
     These macros classify character-coded integer values by
     table lookup.  Each is a predicate returning nonzero for
     true, zero for false.  isascii is defined on all integer
     values; the rest are defined only where isascii is true and
     on the single non-ASCII value EOF (-1); see intro(3).

     isalpha
          c is a letter.

     isupper
          c is an uppercase letter.

     islower
          c is a lowercase letter.

     isdigit
          c is a digit [0-9].

     isxdigit
          c is a hexadecimal digit [0-9], [A-F] or [a-f].

     isalnum
          c is an alphanumeric (letter or digit).

     isspace
          c is a space, tab, carriage return, newline, vertical
          tab, or form-feed.

     ispunct
          c is a punctuation character (neither control nor
          alphanumeric).

     isprint
          c is a printing character, code 040 (space) through
          0176 (tilde).

     isgraph
          c is a printing character, similar to isprint except



January 1992                                                    1

ctype(3C)                                               ctype(3C)



          false for space.

     iscntrl
          c is a delete character (0177) or an ordinary control
          character (less than 040).

     isascii
          c is an ASCII character, code less than 0200.

STATUS MESSAGES AND VALUES
     If the argument to any of these macros is not in the domain
     of the function, the result is undefined.

SEE ALSO
     intro(3), ascii(5)








































2                                                    January 1992