ISCNTRL(3P)						     POSIX Programmer's Manual						       ISCNTRL(3P)

PROLOG

       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME

       iscntrl, iscntrl_l -- test for a control character

SYNOPSIS

       #include <ctype.h>

       int iscntrl(int c);
       int iscntrl_l(int c, locale_t locale);

DESCRIPTION

       For iscntrl(): The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements
       described here and the ISO C standard is unintentional. This volume of POSIX.1-2008 defers to the ISO C standard.

       The  iscntrl()  and iscntrl_l() functions shall test whether c is a character of class cntrl in the current locale, or in the locale repre-
       sented by locale, respectively; see the Base Definitions volume of POSIX.1-2008, 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.

       The  behavior  is  undefined  if  the locale argument to iscntrl_l() is the special locale object LC_GLOBAL_LOCALE or is not a valid locale
       object handle.

RETURN VALUE

       The iscntrl() and iscntrl_l() functions shall return non-zero if c is a control character; otherwise, they 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 these functions and the  functions  in  the  reference  pages
       listed in the SEE ALSO section should be used for character classification.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       isalnum(), isalpha(), isblank(), isdigit(), isgraph(), islower(), isprint(), ispunct(), isspace(), isupper(), isxdigit(), setlocale(), use-
       locale()

       The Base Definitions volume of POSIX.1-2008, Chapter 7, Locale, <ctype.h>, <locale.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol-
       ogy  --	Portable  Operating  System  Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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 Stan-
       dard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE
/The Open Group						       2013							       ISCNTRL(3P)