bdflush(2)

💖 bdflush(2) 💖

okay bestie so we're in the System Calls Manual, section 2, and the star of the show is bdflush — yes that's the whole name, she's lowkey giving sleepy daemon energy and honestly? iconic. 🌸

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✨ NAME ✨

bdflush — start, flush, or tune buffer-dirty-flush daemon 🫧

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🎀 SYNOPSIS 🎀

#include <sys/kdaemon.h>

int bdflush(int func, long data);

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💅 DESCRIPTION 💅

okay so back in the day this system call used to do a whole lot: it could turn the calling process into the bdflush daemon, or tune that daemon, or flush the "old buffers". she was booked, busy, employed. 🙈

and then... she progressively lost all of that functionality. not some. all. the way the job just kept getting smaller until there was no job left 😭💀

so if you wanna know what bdflush actually does on whatever kernel you're snooping on, go read fs/buffer.c in the kernel version you're interested in. that's the real one, fr fr. 👑

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🔥 ERRORS 🔥

• ENOSYS — this system call is unimplemented. that's it. that's the whole list. she's not here rn. 💀

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🌈 STANDARDS 🌈

Linux. (just Linux. periodt. 💅)

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🦋 HISTORY 🦋

omg okay the lore is genuinely so good, sit down, get a snack 🍓:

• introduced in Linux 1.1.3 ✨
• became effectively obsolete in Linux 1.3.50
• mostly useless in Linux 2.3.23
• entirely useless in Linux 2.5.12
• officially deprecated in Linux 2.5.52
• and removed outright in Linux 5.15 ⚰️

she really said "I'll see myself out" over the course of like three decades. character development. main character energy fr. 👑

also, sometimes, if func was even, data actually represented a pointer. 🫠 yeah. just a little chaos. no cap.

and the header and prototype were removed in glibc 2.23, so don't go looking for her there either. 🧚

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👑 SEE ALSO 👑

sync(1), fsync(2), sync(2) — the ones who actually showed up for the shift. 🫶

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well bestie, that's the whole page!! this was Linux man-pages 6.20, dated 2026-02-08, and honestly she ate 💅✨ if you ever need a syscall that does basically nothing, you know where to find her (spoiler: you don't, she's gone 💖).