tcflush(3)

💖 tcflush — bestie edition 💖

okay so this one is a page from the Library Functions Manual, and it's called tcflush(3). yes the (3) is part of the name, that's just how library-call girlies do it 🎀 it lives in the Standard C library, a.k.a. libc, a.k.a. -lc when you're linking. iconic. periodt.

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✨ NAME ✨

tcflush — discard pending data 💅

like. it throws away the leftovers. the un-sent, the un-read. ghosting your terminal data fr fr.

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🫶 LIBRARY 🫶

Standard C library (libc, -lc)

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🌸 SYNOPSIS 🌸

#include <termios.h>

int tcflush(int fd, int queue_selector);

two args, one int for the file descriptor, one int for the queue selector. simple. clean. lowkey elegant.

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💜 DESCRIPTION 💜

so tcflush() discards data. and which data it discards depends entirely on queue_selector, okay bestie, pay attention:

• it'll toss data written to the object that fd refers to but that hasn't actually been transmitted yet, or
• it'll toss data that's been received but hasn't been read yet.

and the queue_selector values are:

• TCIFLUSH — flushes data received but not read. bye bestie 👋
• TCOFLUSH — flushes data written but not transmitted. never made it out the door 💀
• TCIOFLUSH — flushes BOTH of them: data received but not read, AND data written but not transmitted. equal opportunity deletion. slay.

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⭐ RETURN VALUE ⭐

• 0 — on success 🎉 everything's fine, nothing to worry about, go off
• -1 — on failure, and it sets errno to indicate the error 😭 check your errno, that's the whole point

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🦋 ATTRIBUTES 🦋

for an explanation of the terms used in this section, go peek at attributes(7) — it's giving homework but it's worth it.

• interface: tcflush()
  • attribute: Thread safety
  • value: MT-Safe ✨ (yes bestie, you can call it from multiple threads, it's safe, we love that for us)

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🎀 STANDARDS 🎀

POSIX.1-2008. that's the one. 👑

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🌈 HISTORY 🌈

POSIX.1-2001. so it's been around a while — vintage, but make it fashion 💅

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👑 SEE ALSO 👑

• tcsendbreak(3)
• tcdrain(3)
• tcflow(3)
• termios(7)

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just a lil reminder bestie: flushing means the data is gone. discarded. not queued, not saved, not buffered somewhere cute. if you weren't done with it, that's on you 🙈

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and that's the whole page!! this one came from Linux man-pages 6.20, dated 2026-07-02 — shoutout to the man-pages girlies for keeping the docs fed 🫶 mwah, go flush responsibly 💖✨