fpurge(3)

✨ fpurge(3) — Library Functions Manual ✨

okay bestie, pull up a chair 🫶 today we're talking about fpurge and its chaotic sibling __fpurge — the "purge a stream" girlies of the manual pages. welcome to the Library Functions Manual 💅

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🌸 NAME 🌸

fpurge, __fpurge — purge a stream 🧹✨

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📚 LIBRARY 📚

Standard C library (libc, -lc) 🎀

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🦋 SYNOPSIS 🦋

okay so there's the version that nobody supports and the version that's actually supported, and the manpage wants you to know the difference upfront, so:

the unsupported one 🙈:

/* unsupported */
#include <stdio.h>

int fpurge(FILE *stream);

the supported one 👑:

/* supported */
#include <stdio.h>
#include <stdio_ext.h>

void  __fpurge(FILE *stream);

periodt. 💅

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💖 DESCRIPTION 💖

so, the function fpurge() does one thing and does it well: it clears the buffers of the given stream. that's the vibe. 🧚

what "clearing" actually means depends on which way the stream is flowing:

• for output streams, it discards any unwritten output — like, bye, we're not sending that 💀
• for input streams, it discards any input that's already been read off the underlying object but hasn't been handed to you yet via getc(3). and yes bestie, this includes any text you pushed back with ungetc(3). it's gone, fr fr.

also see fflush(3) if you want the more famous cousin. iykyk.

the function __fpurge() does precisely the same thing, except it doesn't bother returning a value. no thoughts, just purge. ✨

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🌈 RETURN VALUE 🌈

• if it works? fpurge() returns 0 — slay 🎉
• if it doesn't? it returns -1 and sets errno to tell you what went wrong 😭

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🍓 ERRORS 🍓

• EBADF — stream is not an open stream. like girl, that's not even a stream, what are we doing here 🙈

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💜 ATTRIBUTES 💜

for an explanation of the terms used in this section, go peek at attributes(7) — but here's the tea:

• __fpurge() — Thread safety: MT-Safe race:stream ⭐

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🎀 STANDARDS 🎀

None. 😶 nothing. zero. the standards girlies said "not us". 💀

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🔥 HISTORY 🔥

• fpurge() — 4.4BSD. Not available under Linux. ok that's important, do not come for me if you try it on Linux 👑
• __fpurge() — Solaris, glibc 2.1.95. she's been around a minute 💅

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⭐ NOTES ⭐

Usually it is a mistake to want to discard input buffers. 🫶

like, lowkey listen to the manpage on this one bestie, she knows what she's talking about.

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👑 SEE ALSO 👑

fflush(3), setbuf(3), stdio_ext(3)

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and that's the whole page, babe — brought to you by Linux man-pages 6.20, dated 2026-02-08, filed under fpurge(3) 💖✨ mwah, go purge responsibly 🎀