fputwc(3)

💖 fputwc — bestie edition 💖

okay so this is fputwc(3) from the Library Functions Manual (we're in the fputwc / putwc cinematic universe, get comfy 🍓)

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✨ NAME ✨

fputwc, putwc — write a wide character to a FILE stream 👑

📚 LIBRARY 📚

Standard C library (libc, -lc) — she's built in, no extra installs, we love that for us 💅

🌸 SYNOPSIS 🌸

#include <stdio.h>
#include <wchar.h>

wint_t fputwc(wchar_t wc, FILE *stream);
wint_t putwc(wchar_t wc, FILE *stream);

🦋 DESCRIPTION 🦋

So fputwc() is literally the wide-character equivalent of fputc(3), no cap. She writes the wide character wc to stream. That's the whole job. Main character energy fr fr.

Here's the vibe check on what she returns and when:

• If ferror(stream) becomes true, she returns WEOF 😭
• If a wide-character conversion error happens, she sets errno to EILSEQ and returns WEOF 💀
• Otherwise? She returns wc. Iconic. We ate. ✨

Now putwc() — the function or macro — functions identically to fputwc(). But bestie, listen: it may be implemented as a macro, and it may evaluate its argument more than once 🙈. And the manpage is very blunt about her: there is no reason ever to use it. periodt.

If you want the nonlocking counterparts, go see unlocked_stdio(3) 🧚

🎀 RETURN VALUE 🎀

On success, fputwc() returns wc 🫶. Otherwise, WEOF is returned, and errno is set to indicate the error. Not the glow-up we wanted but that's the deal 💜

🌈 ERRORS 🌈

Apart from the usual ones, there is:

• EILSEQ — Conversion of wc to the stream's encoding fails. She simply cannot do it, and she's telling you 💀

⭐ ATTRIBUTES ⭐

For an explanation of the terms used in this section, see attributes(7).

• fputwc(), putwc() — Thread safety: MT-Safe 🔥

(yes girl, she's thread safe, we stan a stable queen)

👑 STANDARDS 👑

C11, POSIX.1-2008.

💜 HISTORY 💜

C99, POSIX.1-2001. She's been around, she's established, she's legacy in the best way 🌸

💅 NOTES 💅

The behavior of fputwc() depends on the LC_CTYPE category of the current locale. Locale girlies, this one's for you 🌍

In the absence of additional information passed to the fopen(3) call, it is reasonable to expect that fputwc() will actually write the multibyte sequence corresponding to the wide character wc. So like, expect bytes, get bytes, that tracks 💖

🔗 SEE ALSO 🔗

fgetwc(3), fputws(3), unlocked_stdio(3)

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and that's the tea ☕ this whole page is straight from the Linux man-pages 6.20, dated 2026-02-08, and it's giving fputwc(3). love that for us, bye bestie 🎀💖✨