PR_MCE_KILL_SET(2const)

💅 PR_MCE_KILL_SET (a 2const moment) ✨

okay bestie, so this is one of those little constant pages that rides along with prctl(2) — it's the manual page PR_MCE_KILL_SET, and honestly? it's giving "short but important." no cap. 🎀

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🦋 NAME 🦋

PR_MCE_KILL_SET — set the machine check memory corruption kill policy

like... you're literally deciding how your process gets taken out when the hardware starts lying to you. main character energy fr fr 💀

📚 LIBRARY 📚

Standard C library (libc, -lc)

the classic. the iconique. linking against it as we speak 🫶

✨ SYNOPSIS ✨

#include <linux/prctl.h>  /* Definition of PR_* constants */
#include <sys/prctl.h>

int prctl(PR_MCE_KILL, PR_MCE_KILL_SET, long pol, 0L, 0L);

so you #include both headers — yes BOTH, the linux/prctl.h one is where the PR_* constants live, iykyk — and then you call prctl(2) with PR_MCE_KILL as the first arg, PR_MCE_KILL_SET as the second, your pol sitting in the third slot, and then... 0L, 0L. those two trailing zeros are just vibing there. they're required, they're unused, they're iconic. 🌸

🎀 DESCRIPTION 🎀

so what you're doing here is setting a thread-specific memory corruption kill policy. like, this thread gets its own rules. not the whole process, not the system — just this lil thread. periodt.

and pol is the whole personality of the thing. it's gotta be one of these three:

• PR_MCE_KILL_EARLY — the early kill vibe. 🔥
• PR_MCE_KILL_LATE — the late kill vibe. 🕰️
• PR_MCE_KILL_DEFAULT — whatever the system-wide default is. the "I trust the universe" option. 🌈

Early kill means the thread receives a SIGBUS signal as soon as hardware memory corruption is detected inside its address space. like, immediately. the second the vibes go bad. 😭

Late kill mode is different — the process is only killed when it accesses a corrupted page. so it can keep chilling until it actually touches the bad memory. 🙈

and if you want the full tea on what SIGBUS actually is and how it behaves, go read sigaction(2). your girl doesn't gatekeep. 💖

⭐ RETURN VALUE ⭐

• On success — 0 is returned. slay. 💅
• On error — -1 is returned, and errno is set to tell you what went wrong.

no gray area. it's either 0 or it's a whole mood. 👑

💀 ERRORS 💀

• EINVAL — pol is not a valid value.

that's the one and only error on the list. so if your pol is some made-up nonsense, this is the check that catches you. don't test it. 🍓

🌟 STANDARDS 🌟

Linux.

just Linux. that's the whole section. she said what she said. 🧚

💜 HISTORY 💜

Linux 2.6.32.

ancient. a legend. she's been here since 2.6.32 and she's not leaving. 👑

👀 SEE ALSO 👀

• prctl(2)
• PR_MCE_KILL(2const)

go read the parent page prctl(2) for the big picture, and PR_MCE_KILL(2const) for the sibling constants — they're a matched set, fr fr. 💖

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and that's the whole page bestie!! written up in Linux man-pages 6.20, dated 2026-02-08 — so you know it's fresh, you know it's accurate, and you know your girl did the reading so you don't have to. mwah. 💅✨🎀🦋