ISWUPPER(3P)

💅 ISWUPPER(3P) — the POSIX Programmer's Manual, bestie edition

okay so real talk, this page lives in the POSIX Programmer's Manual, and the Linux version of this interface might lowkey not match (so go peek at the Linux man page if you need the Linux tea), or it might just not exist on Linux at all. 🙈

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🌸 PROLOG 🌸

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ — so consult the corresponding Linux manual page for the deets on Linux behavior — or the interface may not be implemented on Linux at all. That's it, that's the whole prolog. 💖

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✨ NAME ✨

iswupper, iswupper_l — test for an uppercase letter wide-character code

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🎀 SYNOPSIS 🎀

#include <wctype.h>

int iswupper(wint_t wc);
int iswupper_l(wint_t wc, locale_t locale);

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🦋 DESCRIPTION 🦋

For iswupper(): 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 — no drama, it's not on purpose. This volume of POSIX.1‐2017 defers to the ISO C standard.

The iswupper() and iswupper_l() functions shall test whether wc is a wide-character code representing a character of class upper in the current locale, or in the locale represented by locale, respectively. (For the full lore, see the Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale. 📖)

The wc argument is a wint_t, and the value of it is something the application shall ensure is 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.

⚠️ If the argument has any other value, the behavior is undefined. Not "probably fine", not "yolo" — undefined. So don't do it. 💀

Also, the behavior is undefined if the locale argument to iswupper_l() is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle. Both of those are a no. 🙅‍♀️

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🔥 RETURN VALUE 🔥

The iswupper() and iswupper_l() functions shall return non-zero if wc is an uppercase letter wide-character code; otherwise, they shall return 0. Simple as that, periodt. ✨

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💀 ERRORS 💀

No errors are defined. None. Zero. Nothing to report, bestie.

The following sections are informative (iykyk — that means they're the bonus commentary, not the rules).

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🌈 EXAMPLES 🌈

None. 😭 (I know. Devastating. No example to slay with today.)

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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 go rogue with your own classification vibes, okay? 👑

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🧚 RATIONALE 🧚

None. Moving on. 💅

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⭐ FUTURE DIRECTIONS ⭐

None. The future is... also nothing. Iconic, honestly.

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🫶 SEE ALSO 🫶

• iswalnum()
• iswalpha()
• iswcntrl()
• iswctype()
• iswdigit()
• iswgraph()
• iswlower()
• iswprint()
• iswpunct()
• iswspace()
• 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. (So if we ever beef, they win. 🥲) 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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and that's the whole page, bestie!! brought to you by IEEE/The Open Group, 2017 — ISWUPPER(3P), mwah 💋✨