NAME

       iscntrl - test for a control character

SYNOPSIS

       #include <ctype.h>

       int iscntrl(int c);

DESCRIPTION

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

       The  c  argument  is  a  type  int,  the  value of which the application shall ensure is a
       character 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  iscntrl()  function  shall return non-zero if c is a control 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

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