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NAME

       isalnum - test for an alphanumeric character

SYNOPSIS

       #include <ctype.h>

       int isalnum(int c);

DESCRIPTION

       The  isalnum()  function  shall  test whether c is a character of class
       alpha  or  digit  in  the  program’s  current  locale;  see  the   Base
       Definitions volume of IEEE Std 1003.1-2001, Chapter 7, Locale.

       The  c  argument  is  an  int, the value of which the application shall
       ensure is representable as an unsigned char or equal to  the  value  of
       the  macro  EOF.  If  the argument has any other value, the behavior is
       undefined.

RETURN VALUE

       The isalnum() function shall return non-zero if c  is  an  alphanumeric
       character; otherwise, it shall return 0.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       To   ensure   applications   portability,   especially  across  natural
       languages, only this function and those listed in the SEE ALSO  section
       should be used for character classification.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       isalpha() , iscntrl() , isdigit() , isgraph() , islower() , isprint() ,
       ispunct() , isspace() , isupper() , isxdigit() , setlocale() , the Base
       Definitions   volume   of   IEEE Std 1003.1-2001,  Chapter  7,  Locale,
       <ctype.h>, <stdio.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard
       is  the  referee document. The original Standard can be obtained online
       at http://www.opengroup.org/unix/online.html .