iswcntrl(3)

✨ iswcntrl — test for control wide character ✨

okay bestie, gather round, we're doing iswcntrl(3) from the Library Functions Manual and honestly it's a little cutie. 💖 It lives in the Standard C library (libc, -lc) so like, she's already there for you, no extra linking drama. 🫶

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🌸 SYNOPSIS 🌸

#include <wctype.h>

int iswcntrl(wint_t wc);

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🎀 DESCRIPTION 🎀

So iswcntrl() is literally just the wide-character glow-up of iscntrl(3), no cap. 💅 She looks at wc and tells you if it's a wide character that belongs to the wide-character class "cntrl".

And here's the tea: the "cntrl" class is disjoint from the "print" class — meaning there's zero overlap, they don't know each other, they don't text back 😭 — and because of that it's also disjoint from all of "print"'s lil subclasses: "graph", "alpha", "upper", "lower", "digit", "xdigit", and "punct". Periodt.

Also for an unsigned char c: iscntrl(c) implies iswcntrl(btowc(c)), but not the other way around. One-way street, iykyk. 🚦

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💖 RETURN VALUE 💖

• She hands you nonzero if wc is a wide character in the wide-character class "cntrl". slay. ✨
• Otherwise? zero. humble. 🙈

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👑 ATTRIBUTES 👑

for the whole explanation of what these terms even mean, go check attributes(7) — that's the homework bestie 📚

• iswcntrl() — Thread safety: MT-Safe locale 🧚

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🌈 STANDARDS 🌈

C11, POSIX.1-2008. certified iconic. ⭐

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🦋 HISTORY 🦋

She's been around: POSIX.1-2001, C99. an elder, a legend, a main character. 👑

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💀 NOTES 💀

the behavior of iswcntrl() depends on the LC_CTYPE category of the current locale 🌍

so like, don't be shocked when she acts different in a different locale, that's just her vibe check.

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💜 SEE ALSO 💜

• iscntrl(3)
• iswctype(3)

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and that's a wrap on iswcntrl(3) from Linux man-pages 6.20, dated 2026-02-08 🎀 go forth and test your control wide characters, bestie, you ate fr fr 💅✨🫶