iswalnum(3)

✨ iswalnum(3) ✨

okay bestie, get comfy, we're doing iswalnum today and it's literally the moment. this is the wide-character version of isalnum(3) — same energy, bigger characters, no thoughts just checking. 🌸

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💖 LIBRARY 💖

Standard C library (libc, -lc) — yeah babe, the classic.

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🎀 SYNOPSIS 🎀

#include <wctype.h>

int iswalnum(wint_t wc);

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🦋 DESCRIPTION 🦋

iswalnum() is the wide-character equivalent of isalnum(3), fr fr. it looks at wc and tells you whether it's a wide character that belongs to the wide-character class "alnum". that's the whole job. iconic, honestly.

the wide-character class "alnum" is a subclass of the wide-character class "graph", and therefore also a subclass of "print". it's giving hierarchy. 👑

since it's a subclass of "print", the class "alnum" is disjoint from "cntrl" — they do not overlap, not even a little, no cap.

since it's a subclass of "graph", "alnum" is disjoint from "space" and from "space"'s own subclass "blank". like, different worlds, separate lanes. 💅

"alnum" is also disjoint from "punct". punctuation could never. 💀

and get this — the wide-character class "alnum" is the union of the wide-character classes "alpha" and "digit". so it's the whole friend group. and because of that, it also contains the wide-character class "xdigit". obsessed. 🔥

also, "alnum" always contains at least the letters 'A' to 'Z', 'a' to 'z', and the digits '0' to '9'. those are non-negotiable, they're always in the group chat. ✨

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🌈 RETURN VALUE 🌈

• if wc is a wide character belonging to the wide-character class "alnum" → iswalnum() returns nonzero (it said yes 💖)
• otherwise → it returns zero (it said no 🙈)

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👑 ATTRIBUTES 👑

for an explanation of the terms used in this section, go check attributes(7). ✨

• iswalnum() — Thread safety — MT-Safe locale

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⭐ STANDARDS ⭐

C11, POSIX.1-2008. periodt.

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🧚 HISTORY 🧚

POSIX.1-2001, C99.

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🍓 NOTES 🍓

heads up bestie: the behavior of iswalnum() depends on the LC_CTYPE category of the current locale. so like, locale changes everything. it's not a fixed vibe, iykyk. 🌍

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💜 SEE ALSO 💜

• isalnum(3)
• iswctype(3)

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and that's the whole page, babe, you killed it 💅 the source is Linux man-pages 6.20 and the date on it is 2026-02-08 — go forth and classify your wide characters responsibly 🫶✨