ISWCNTRL(3POSIX)

💖 ISWCNTRL(3POSIX) 💖

okay bestie, welcome to the POSIX Programmer's Manual — yes that's the whole manual, and yes this page is part of it. sit down, hydrate, we're learning about control wide-character codes 🎀

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✨ PROLOG ✨

so like, heads up first: this manual page is part of the POSIX Programmer's Manual. the Linux implementation of this interface may differ — so if you're on Linux, pls consult the corresponding Linux manual page for the deets on Linux behavior. or, plot twist, the interface might not even be implemented on Linux at all. 💀 vibe check accordingly.

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🌸 NAME 🌸

iswcntrl, iswcntrl_l — test for a control wide-character code. that's it. that's the job. 🦋

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✨ SYNOPSIS ✨

#include <wctype.h>

int iswcntrl(wint_t wc);
int iswcntrl_l(wint_t wc, locale_t locale);

two functions, one header, we love a clean entrance. 💅

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🎀 DESCRIPTION 🎀

okay so for iswcntrl(): the functionality described on this reference page is aligned with the ISO C standard. and if there's any conflict between the requirements described here and the ISO C standard? that's unintentional, fr fr. this volume of POSIX.1‐2017 defers to the ISO C standard. the ISO C standard is the main character here, we're just supporting cast. 👑

now the actual tea: iswcntrl() and iswcntrl_l() shall test whether wc is a wide-character code representing a character of class cntrl in the current locale, or in the locale represented by locale, respectively. see the Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale. 🗺️

the wc argument is a wint_t, and the value of it? the application shall ensure it's a wide-character code corresponding to a valid character in the locale used by the function, or equal to the value of the macro WEOF.

🚨 and if the argument has any other value? the behavior is undefined. not a vibe. don't do it. 😭

also, the behavior is undefined if the locale argument to iswcntrl_l() is the special locale object LC_GLOBAL_LOCALE, or if it's not a valid locale object handle. like, invalid locale handle = chaos. 🙈

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⭐ RETURN VALUE ⭐

iswcntrl() and iswcntrl_l() shall return non-zero if wc is a control wide-character code. otherwise? they shall return 0. simple. binary. iconic. ✨

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💀 ERRORS 💀

No errors are defined.

the following sections are informative. (translation: the drama is over, the rest is bonus content 🍓)

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🌈 EXAMPLES 🌈

None.

not one example. we're on our own, bestie. 🫶

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💜 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. don't freestyle with random stuff, iykyk. 🌍

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🦋 RATIONALE 🦋

None.

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🧚 FUTURE DIRECTIONS 🧚

None.

nothing coming. the future is quiet. 🎀

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👑 SEE ALSO 👑

• iswalnum()
• iswalpha()
• iswctype()
• iswdigit()
• iswgraph()
• iswlower()
• iswprint()
• iswpunct()
• iswspace()
• iswupper()
• iswxdigit()
• setlocale()
• uselocale()

also, the Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale, plus <locale.h> and <wctype.h>. 🌸

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💅 COPYRIGHT 💅

portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

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 .

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okay that's the whole page, you ate it up 🍓✨ huge shoutout to IEEE/The Open Group, 2017, for bringing us ISWCNTRL(3POSIX) — go forth and classify your control wide-character codes responsibly, bestie 💖🦋