ISUPPER(3P)

✨ ISUPPER(3P) ✨

okay bestie, so this one is from the POSIX Programmer's Manual — that's the manual, and the page is ISUPPER(3P) 💅 it's giving "am I a capital letter or not" energy and honestly? iconic.

🎀 PROLOG

So this manual page is part of the POSIX Programmer's Manual, okay? But heads up: the Linux implementation of this interface may differ — like, consult the corresponding Linux manual page for the deets on Linux behavior — or the interface may literally not be implemented on Linux at all. 💀 no cap.

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💖 NAME

isupper, isupper_l — test for an uppercase letter 🔠✨

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🌸 SYNOPSIS

#include <ctype.h>

int isupper(int c);
int isupper_l(int c, locale_t locale);

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🦋 DESCRIPTION

So, for isupper(): 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 — nobody's trying to start drama. This volume of POSIX.1‐2017 defers to the ISO C standard. periodt. 💅

The isupper() and isupper_l() functions shall test whether c is a character of class upper in the current locale, or in the locale represented by locale, respectively. like, one uses the current vibe and the other uses the locale you hand it. see the Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale for the full lore. 📖

The c argument is an 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 — so like, don't do that, fr fr. 😭

The behavior is undefined if the locale argument to isupper_l() is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle. Not me passing a garbage locale and wondering why everything's on fire 🙈

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🌈 RETURN VALUE

The isupper() and isupper_l() functions shall return non-zero if c is an uppercase letter; otherwise, they shall return 0. simple as that, bestie — truthy or falsy, no in-between. ✨

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⭐ ERRORS

No errors are defined. 🫶

The following sections are informative — so like, they're the bonus content, not the rules. 👑

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🍓 EXAMPLES

None. (yeah, the well is dry, we move. 💀)

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👑 APPLICATION USAGE

To ensure applications portability — especially across natural languages, because the world is big and beautiful 🌍 — only these functions and the functions in the reference pages listed in the SEE ALSO section should be used for character classification. don't get creative with it, babe, that's the move. 💜

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🧚 RATIONALE

None.

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🎀 FUTURE DIRECTIONS

None.

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🔥 SEE ALSO

• isalnum()
• isalpha()
• isblank()
• iscntrl()
• isdigit()
• isgraph()
• islower()
• isprint()
• ispunct()
• isspace()
• isxdigit()
• setlocale()
• uselocale()

The Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale, <ctype.h>, <locale.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 — like, the original is the main character here, not this page. 👑

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 — yes, the footer said ISUPPER(3P) and 2017 and we are respecting the timeline. now go check your letters, you gorgeous uppercase icon. 💅✨🌸