ISWDIGIT(3POSIX)

🦋 ISWDIGIT — the "is this a digit, bestie?" page 🦋

ok so real talk: this is part of the POSIX Programmer's Manual ✨ Heads up though — the Linux implementation of this interface may differ (so pls go check the matching Linux manual page for the actual Linux tea 🫖), or honestly the interface might not even be implemented 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 (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

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💖 NAME 💖

iswdigit, iswdigit_l — test for a decimal digit wide-character code 👑

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✨ SYNOPSIS ✨

#include <wctype.h>

int iswdigit(wint_t wc);
int iswdigit_l(wint_t wc, locale_t locale);

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🎀 DESCRIPTION 🎀

So, for iswdigit(): 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 intended fr. This volume of POSIX.1‐2017 defers to the ISO C standard.

The iswdigit() and iswdigit_l() functions shall test whether wc is a wide-character code representing a character of class digit in the current locale, or in the locale represented by locale, respectively — like, current locale for the first one, the locale you hand over for the second one. 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. If the argument has any other value, the behavior is undefined. 💀 like, not "undefined-ish", actually undefined, bestie.

🚨 Also: the behavior is undefined if the locale argument to iswdigit_l() is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle. Don't do that. Seriously.

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⭐ RETURN VALUE ⭐

The iswdigit() and iswdigit_l() functions shall return non-zero if wc is a decimal digit wide-character code; otherwise, they shall return 0. That's it, that's the whole vibe check. 💅

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🌈 ERRORS 🌈

No errors are defined. ✨ (iconic behavior honestly)

The following sections are informative.

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🍓 EXAMPLES 🍓

None. 😭 not a single one. we move.

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🧚 APPLICATION USAGE 🧚

To ensure applications portability — especially across natural languages, which is highkey the whole point — only these functions and the functions in the reference pages listed in the SEE ALSO section should be used for character classification. no DIY-ing it, ok? 🫶

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💜 RATIONALE 💜

None.

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🌸 FUTURE DIRECTIONS 🌸

None.

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🔥 SEE ALSO 🔥

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

The Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale, <locale.h>, <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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and that's the whole page, bestie 🎀 this one's brought to you by IEEE/The Open Group, 2017 — go forth and classify your wide characters responsibly 💖✨