NAME

       isalnum,  isalpha,  iscntrl,  isdigit,  isgraph,  islower,
       isprint, ispunct, isspace, isupper, isxdigit  -  character
       classification routines

SYNOPSIS

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

DESCRIPTION

       These functions check whether c, which must have the value
       of an unsigned char or EOF, falls into a certain character
       class according to the current locale.
       isalnum()
              checks for an alphanumeric character; it is equiva-
              lent to (isalpha(c) || isdigit(c)).
       isalpha()
              checks for an alphabetic character; it  is  equiva-
              lent to (isupper(c) || islower(c)).
       iscntrl()
              checks for a control character.
       isdigit()
              checks for a digit.
       isgraph()
              checks for any printable character except space.
       islower()
              checks for a lower - case character.
       isprint()
              checks for any printable character including space.
       ispunct()
              checks for any printable character which is  not  a
              space or an alphanumeric character.
       isspace()
              checks  for  white  - space characters.  In the "C"
              and "POSIX" locales, these  are:  space,  form-feed
              ('\f'),  newline  ('\n'),  carriage  return ('\r'),
              horizontal tab ('\t'), and vertical tab ('\v').
       isupper()
              checks for an uppercase letter.
       isxdigit()
              checks for a hexadecimal digits, i.e. one of 0 1  2
              3 4 5 6 7 8 9 0 a b c d e f A B C D E F

RETURN VALUE

       The  values  returned are nonzero if the character c falls
       into the tested class, and a zero value if not.

CONFORMS TO

       ANSI - C, BSD 4.3

BUGS

       The details of what characters  belong  into  which  class
       depend on the current locale.  For example, isupper() will
       not recognize an A - umlaut as an uppercase letter in  the
       default C locale.

SEE ALSO

       toupper(3), setlocale(3), ascii(7), locale(7)