mbsinit(3)

💅 mbsinit — like, is this shift state even initialized bestie

okay so picture this: you're deep in mbsinit(3) from the Linux man-pages, living your best life in the multibyte world, and you just need to know ONE thing — is this mbstate_t fresh or not? That's the whole vibe. It's a tiny little checker function and it eats every single time. 🦋

---

✨ NAME ✨

mbsinit — test for initial shift state 🎀

📚 LIBRARY 📚

Standard C library (libc, -lc) — she comes free with your libc, no extra install, no cap.

🌸 SYNOPSIS 🌸

#include <wchar.h>

int mbsinit(const mbstate_t *ps);

💖 DESCRIPTION 💖

So the way that mbsinit() works is it tests whether *ps corresponds to an initial shift state. That's it. That's the function. She's short, she's sweet, she's iconic. ✨

Like genuinely, that's the whole job description — you hand her a pointer to a shift state and she tells you if what's being pointed at is the initial one or not. Periodt.

🫶 RETURN VALUE 🫶

• mbsinit() returns nonzero if *ps is an initial shift state 💚 — OR if ps is NULL (yes bestie, NULL counts as initial, she said what she said).
• Otherwise, it returns 0.

So basically: nonzero = good/initial, zero = not initial. Simple. Clean. We love a binary answer. 👑

🔥 ATTRIBUTES 🔥

For an explanation of the terms used in this section, see attributes(7). (iykyk, it's the glossary situation 💀)

• mbsinit() — Thread safety: MT-Safe ✨🚀

MT-Safe meaning you can call her from multiple threads at once and she will NOT start drama. Queen behavior only. 👑

🌈 STANDARDS 🌈

C11, POSIX.1-2008 — she's officially standardized, she's got papers, she's legit fr fr. 📜

🎀 HISTORY 🎀

POSIX.1-2001, C99 — she's been around since way back, an OG. Respect the elders. 🙏

💜 NOTES 💜

The behavior of mbsinit() depends on the LC_CTYPE category of the current locale. 👀

So lowkey your locale matters here — set your LC_CTYPE and that's what she's going off of. Don't come for her if you didn't configure your locale, bestie. 🫠

🦋 SEE ALSO 🦋

• mbstate_t(3type)
• mbrlen(3)
• mbrtowc(3)
• mbsrtowcs(3)
• wcrtomb(3)
• wcsrtombs(3)

---

and that's the whole page!! 😭💖 this one's from Linux man-pages 6.20, dated 2026-02-08 — go check out that mbstate_t(3type) page next if you wanna know what a shift state even is, mwah 💅✨