wcwidth(3)

✨ wcwidth(3) — the manual page bestie 💅

okay so this is a page from the Library Functions Manual (yes, the libc girlies) and honestly? it's a tiny function with main character energy. let's get into it 🎀

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🦋 NAME

wcwidth — figure out how many columns a wide character takes up, bestie. that's it. that's the whole job.

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📚 LIBRARY

Standard C library (libc, -lc) — she's a classic, no cap.

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🌸 SYNOPSIS

#define _XOPEN_SOURCE       /* See feature_test_macros(7) */
#include <wchar.h>

int wcwidth(wchar_t wc);

like, you gotta define _XOPEN_SOURCE first (peep feature_test_macros(7) for the lore 💖) and then pull in <wchar.h>.

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💖 DESCRIPTION

so wcwidth() literally returns the number of columns you need to represent the wide character wc. that's the vibe.

• if wc is a printable wide character, the value is at least 0 ✨
• if wc is the null wide character (L'\0'), the value is 0 🫶
• otherwise? -1 gets returned, and honestly, same 🙈

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👑 RETURN VALUE

wcwidth() hands you back the number of column positions for wc. periodt. 💅

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🌈 ATTRIBUTES

for what all these words even mean, go look at attributes(7) — iykyk.

here's the tea on wcwidth():

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

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⭐ STANDARDS

POSIX.1-2008. iconic. certified. 💯

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🧚 HISTORY

POSIX.1-2001 — she's been around a minute.

and a lil throwback for you: before glibc 2.2.5, glibc was out here using this prototype instead:

int wcwidth(wint_t wc);

not me with the wint_t instead of wchar_t 😭 ancient times fr fr.

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🔥 NOTES

the behavior of wcwidth() depends on the LC_CTYPE category of the current locale. so like... your locale is the one calling the shots here, not you. lowkey humbling. 🌸

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🫶 SEE ALSO

• iswprint(3)
• wcswidth(3)

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vibe check: this is Linux man-pages 6.20, dated 2026-02-08, for wcwidth(3). slay, stay hydrated, and always define _XOPEN_SOURCE before you include anything 💜✨