iswspace(3)

✨ iswspace(3) ✨ — Library Functions Manual 🫶

okay bestie, pull up a chair, we're learning about iswspace 💅 this one is a whole icon in the wide-character world and honestly it's giving "quietly essential" energy.

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🌸 NAME 🌸

iswspace — test for whitespace wide character

📚 LIBRARY 📚

Standard C library (libc, -lc) — yeah, the classic, no cap 🎀

✨ SYNOPSIS ✨

#include <wctype.h>

int iswspace(wint_t wc);

💖 DESCRIPTION 💖

okay so first things first: iswspace() is literally the wide-character equivalent of the isspace(3) function. that's it, that's the vibe. it tests whether wc is a wide character belonging to the wide-character class "space". 🌈

now here's the lore. the wide-character class "space" is disjoint from the wide-character class "graph", which means it's also disjoint from all of graph's subclasses: "alnum", "alpha", "upper", "lower", "digit", "xdigit", and "punct". so no overlap bestie, they do not run in the same circles 💅

meanwhile, the wide-character class "space" contains the wide-character class "blank". so blank is like... a sub-vibe. a little subset. cute. 🎀

and here's the part that's fr fr important: the wide-character class "space" always contains at least the space character and these control characters: '\f', '\n', '\r', '\t', and '\v'. ⭐ like, bare minimum, this is the roster.

🌀 RETURN VALUE 🌀

• iswspace() returns nonzero if wc is a wide character that belongs to the wide-character class "space". slay. ✅
• otherwise it returns zero. not it. 💀

👑 ATTRIBUTES 👑

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

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

so like, it's thread safe, but locale-flavored thread safe. iykyk 🦋

📜 STANDARDS 📜

C11, POSIX.1-2008.

🕰️ HISTORY 🕰️

POSIX.1-2001, C99. so it's been around for a minute, an OG fr fr.

🧚 NOTES 🧚

the behavior of iswspace() depends on the LC_CTYPE category of the current locale. so like, change your locale, change the answer. 🙈

real talk: this function is locale-sensitive, so don't act surprised when the result shifts depending on where you are. 💖

🔥 SEE ALSO 🔥

• isspace(3)
• iswctype(3)

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okay that's the whole page, you ate that 🫶 this little deep-dive brought to you by Linux man-pages 6.20, dated 2026-02-08, for iswspace(3). go forth and check your whitespace, bestie 💜✨