wctype(3)

💖 wctype(3) — the wide-char vibe check function 💖

okay bestie, so we're in section 3 of the manual, which means we're talking library functions, and today's main character is wctype. she lives in the Standard C library (libc, link with -lc when you're compiling, mwah). let's get into it 🦋

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✨ SYNOPSIS ✨

#include <wctype.h>

wctype_t wctype(const char *name);

that's it. one function, one const char *, she's lowkey simple but she's doing so much for us 🫶

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🌸 DESCRIPTION 🌸

okay so first let's talk about the type, because wctype_t is the whole point.

wctype_t represents a property that a wide character might or might not have. like, it's a whole class of wide characters, not one specific character. and here's the tea: what this type actually is on the inside is implementation-dependent — nobody's promising you it looks any particular way. BUT. there's one thing everyone agrees on:

the special value (wctype_t) 0 means "invalid property". that's the zero. it's the "no thanks". it's the ick.

and any nonzero wctype_t value can be handed straight to iswctype(3) to actually test whether some given wide character has that property. so wctype() is like — you ask for the property, iswctype() is the one who checks whether your character qualifies. they're a duo fr fr 👑

So, the actual function: wctype() returns a property, and you get to pick it by name. which names are valid? that depends on the LC_CTYPE category of your current locale — locale-dependent, as always, she's dramatic like that. BUT these following names are valid in every single locale, no cap:

• "alnum" — realizes the isalnum(3) classification function ✨
• "alpha" — realizes the isalpha(3) classification function ✨
• "blank" — realizes the isblank(3) classification function ✨
• "cntrl" — realizes the iscntrl(3) classification function ✨
• "digit" — realizes the isdigit(3) classification function ✨
• "graph" — realizes the isgraph(3) classification function ✨
• "lower" — realizes the islower(3) classification function ✨
• "print" — realizes the isprint(3) classification function ✨
• "punct" — realizes the ispunct(3) classification function ✨
• "space" — realizes the isspace(3) classification function ✨
• "upper" — realizes the isupper(3) classification function ✨
• "xdigit" — realizes the isxdigit(3) classification function ✨

twelve of them, all iconic, all present everywhere. slay 💅

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🎀 RETURN VALUE 🎀

• if the name you passed is valid → you get a property descriptor back. congratulations, she ate 🍓
• otherwise → you get (wctype_t) 0. aka the invalid-property value. aka the void. aka not me getting zero again 😭

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👑 ATTRIBUTES 👑

for an explanation of the terms used in this section, go peek at attributes(7). 💜

• Interface: wctype()
  • Attribute: Thread safety
  • Value: MT-Safe locale

so like, thread-safe, but locale-thread-safe, iykyk — the locale part is doing work in that sentence. 🌈

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🌟 STANDARDS 🌟

C11, POSIX.1-2008. certified, blessed, official. periodt. ✅

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🧚 HISTORY 🧚

POSIX.1-2001, C99. so she's been around, she's a legacy icon, she predates most of us knowing what a locale even is 💀

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⭐ NOTES ⭐

the behavior of wctype() depends on the LC_CTYPE category of the current locale.

read that again bestie. it depends on the current locale. change your locale, change what names work. it's giving main character energy with a mood ring. 🙈

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🦋 SEE ALSO 🦋

• iswctype(3) — the other half of the duo 💞

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and that's the whole thing! this page came to you courtesy of Linux man-pages 6.20, dated 2026-02-08 — okay love you bye, go classify some wide characters responsibly 💖✨🎀