1ISCNTRL(3P)                POSIX Programmer's Manual               ISCNTRL(3P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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11

NAME

13       iscntrl, iscntrl_l — test for a control character
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SYNOPSIS

16       #include <ctype.h>
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18       int iscntrl(int c);
19       int iscntrl_l(int c, locale_t locale);
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DESCRIPTION

22       For iscntrl(): The functionality described on this  reference  page  is
23       aligned  with the ISO C standard. Any conflict between the requirements
24       described here and the ISO C standard is unintentional. This volume  of
25       POSIX.1‐2008 defers to the ISO C standard.
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27       The iscntrl() and iscntrl_l() functions shall test whether c is a char‐
28       acter of class cntrl in the current locale, or  in  the  locale  repre‐
29       sented  by  locale,  respectively;  see  the Base Definitions volume of
30       POSIX.1‐2008, Chapter 7, Locale.
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32       The c argument is a type int, the value of which the application  shall
33       ensure is a character representable as an unsigned char or equal to the
34       value of the macro EOF. If the argument has any other value, the behav‐
35       ior is undefined.
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37       The  behavior is undefined if the locale argument to iscntrl_l() is the
38       special locale object LC_GLOBAL_LOCALE or is not a valid locale  object
39       handle.
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RETURN VALUE

42       The iscntrl() and iscntrl_l() functions shall return non-zero if c is a
43       control character; otherwise, they shall return 0.
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ERRORS

46       No errors are defined.
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48       The following sections are informative.
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EXAMPLES

51       None.
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APPLICATION USAGE

54       To ensure applications  portability,  especially  across  natural  lan‐
55       guages,  only  these functions and the functions in the reference pages
56       listed in the SEE ALSO section should be used for character classifica‐
57       tion.
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RATIONALE

60       None.
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FUTURE DIRECTIONS

63       None.
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SEE ALSO

66       isalnum(),   isalpha(),  isblank(),  isdigit(),  isgraph(),  islower(),
67       isprint(), ispunct(), isspace(),  isupper(),  isxdigit(),  setlocale(),
68       uselocale()
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70       The  Base  Definitions  volume  of  POSIX.1‐2008,  Chapter  7,  Locale,
71       <ctype.h>, <locale.h>
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74       Portions of this text are reprinted and reproduced in  electronic  form
75       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
76       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
77       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
78       cal and Electronics Engineers,  Inc  and  The  Open  Group.   (This  is
79       POSIX.1-2008  with  the  2013  Technical Corrigendum 1 applied.) In the
80       event of any discrepancy between this version and the original IEEE and
81       The  Open Group Standard, the original IEEE and The Open Group Standard
82       is the referee document. The original Standard can be  obtained  online
83       at http://www.unix.org/online.html .
84
85       Any  typographical  or  formatting  errors that appear in this page are
86       most likely to have been introduced during the conversion of the source
87       files  to  man page format. To report such errors, see https://www.ker‐
88       nel.org/doc/man-pages/reporting_bugs.html .
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92IEEE/The Open Group                  2013                          ISCNTRL(3P)
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