ungetwc(3)

💖 ungetwc(3) 💖

okay so bestie, this is a library functions manual page for ungetwc, and it lives in section 3 of the manual. yes we're doing wide characters today. grab a snack. 🍓

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✨ NAME ✨

ungetwc — push back a wide character onto a FILE stream

📚 LIBRARY 📚

Standard C library (libc, -lc)

🌸 SYNOPSIS 🌸

#include <wchar.h>

wint_t ungetwc(wint_t wc, FILE *stream);

🦋 DESCRIPTION 🦋

so <pink>ungetwc()</pink> is literally the wide-character equivalent of the ungetc(3) function. it takes a wide character and pushes it back onto stream, and returns it. giving "sike, I wasn't done with that character" energy. 💅

here's the tea, case by case:

• If wc is WEOF, it returns WEOF. that's it. nothing else happens. bye.
• If wc is an invalid wide character, it sets errno to EILSEQ and returns WEOF. not slay.
• If wc is a valid wide character, it gets pushed back onto the stream and thus becomes available for future wide-character read operations 👑. The file-position indicator is decremented by one or more. The end-of-file indicator is cleared ✨. The backing storage of the file is not affected. no cap.

Note: wc need not be the last wide-character read from the stream; it can be any other valid wide character. iconic behaviour honestly.

If the implementation supports multiple push-back operations in a row, the pushed-back wide characters will be read in reverse order; however, only one level of push-back is guaranteed. so like. one is a promise, more than one is a vibe. 🙈

💫 RETURN VALUE 💫

ungetwc() returns wc when successful, or WEOF upon failure. simple as. 💖

🎀 ATTRIBUTES 🎀

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

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

slay, it's thread safe, go off bestie 🫶

🌈 STANDARDS 🌈

C11, POSIX.1-2008. periodt.

📜 HISTORY 📜

POSIX.1-2001, C99. it's been serving for a minute. 💜

🧚 NOTES 🧚

The behavior of ungetwc() depends on the LC_CTYPE category of the current locale. so like, know your locale, iykyk. 🌍

👀 SEE ALSO 👀

• fgetwc(3)

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and that's the whole page, bestie 💅 this was page ungetwc(3), from Linux man-pages 6.20, dated 2026-02-08, and yes it says Library Functions Manual at the top like a little crown 👑 mwah, go push back some wide characters responsibly, ily 🎀✨