wcstok(3)

✨ wcstok(3) — the wide-character glow-up of strtok(3) ✨

okay bestie, settle in, because we're splitting wide-character strings today and honestly? it's giving main character energy. this page lives in the Library Functions Manual, section 3, and it's all about the standard C library (that's libc, aka -lc) 💖

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🌸 NAME 🌸

wcstok — split a wide-character string into tokens 🎀

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🧚 LIBRARY 🧚

Standard C library (libc, -lc) — yes queen, the regular one, nothing fancy 🫶

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✨ SYNOPSIS ✨

#include <wchar.h>

wchar_t *wcstok(wchar_t *restrict wcs, const wchar_t *restrict delim,
                wchar_t **restrict ptr);

that's it that's the whole vibe 💅

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💜 DESCRIPTION 💜

so wcstok() is literally the wide-character equivalent of strtok(3), except it got a glow-up: it comes with an extra argument that makes it multithread-safe 🔥 iconic behavior, no notes.

you use it to split a wide-character string wcs into tokens, and a token is defined as a substring that contains none of the wide-characters from delim. simple as that 🦋

now here's how the search goes, bestie, pay attention:

• the search starts at wcs — but only if wcs is not NULL
• otherwise it starts at *ptr — that's when wcs is NULL

then? first, any delimiter wide-characters get skipped. like, the pointer just advances past anything in delim, bye 👋

if the end of the wide-character string is reached at that point, wcstok() returns NULL to say "no tokens found, bestie, it's over", and it stores an appropriate value in *ptr so that subsequent calls to wcstok() will just keep returning NULL. the search has left the chat 💀

otherwise — and this is the part where it eats — wcstok() recognizes the beginning of a token and returns a pointer to it. but before it does that, it zero-terminates the token, replacing the next wide-character that occurs in delim with a null wide character (L'\0'), and it updates *ptr so subsequent calls continue searching after the end of the recognized token ✨

⚠️ lowkey important: this is destructive, we get to that in NOTES, don't say I didn't warn you 🙈

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🎀 RETURN VALUE 🎀

wcstok() returns a pointer to the next token, or NULL if no further token was found. that's the whole plot. 🌈

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👑 ATTRIBUTES 👑

for an explanation of the terms used in this section, go peek at attributes(7) — it's the lore doc 📖

• Interface: wcstok()
• Attribute: Thread safety
• Value: MT-Safe 🔥

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🌟 STANDARDS 🌟

C11, POSIX.1-2008 — certified, periodt 💅

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💌 HISTORY 💌

POSIX.1-2001, C99. it's been here for a minute, an elder icon honestly 💖

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🍓 NOTES 🍓

the original wcs wide-character string is destructively modified during the operation. like, it will not survive the encounter bestie. it's being edited in place. if you needed the original, too late, you should've made a copy 🫠

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🦋 EXAMPLES 🦋

the following code loops over the tokens contained in a wide-character string. look at her go:

wchar_t *wcs = ...;
wchar_t *token;
wchar_t *state;
for (token = wcstok(wcs, L" \t\n", &state);
    token != NULL;
    token = wcstok(NULL, L" \t\n", &state)) {
    ...
}

see how wcs is passed on the first call and NULL on every call after? and &state carries the *ptr drip forward? that's the whole trick. chef's kiss 🧑‍🍳💋

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🌈 SEE ALSO 🌈

• strtok(3)
• wcschr(3)

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and that's the tea bestie 💜 this page was brought to you by Linux man-pages 6.20, dated 2026-02-08, and filed under wcstok(3). go forth and tokenize responsibly, mwah 🫶🎀✨