PR_SET_FPEMU(2const)

💅 PR_SET_FPEMU 💅

okay bestie so real talk — this is a page from the 2const girlies, which is just the manual's way of saying "this isn't its own syscall, it's one of those special constants you hand to prctl(2)." And literally, the whole vibe here is: set floating-point emulation control bits. That's it. That's the name. PR_SET_FPEMU 💖

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📚 LIBRARY 📚

Standard C library (libc, -lc). Yep, she's a libc girlie. 🎀

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✨ SYNOPSIS ✨

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

int prctl(PR_SET_FPEMU, long fpemu);

so you're calling prctl(2) like always, and the first arg is literally the constant PR_SET_FPEMU, and the second one is your long fpemu. That's the whole thing. Slay. 🦋

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🌸 DESCRIPTION 🌸

You're setting the floating-point emulation control bits to whatever fpemu says they should be. Iconic behavior honestly.

And then you pick your flavor of fpemu:

• PR_FPEMU_NOPRINT — this one says: silently emulate floating-point operation accesses. No drama, no noise, just vibes. 🤫
• PR_FPEMU_SIGFPE — this one is the opposite energy: do not emulate floating-point operations, and send SIGFPE instead. She's loud. She's telling you something's wrong. 💀

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👑 RETURN VALUE 👑

• On success? You get 0. Periodt. ✨
• On error? You get -1, and errno gets set to tell you what went down. 😭

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🙈 ERRORS 🙈

• EINVAL — fpemu is not a valid value. ma'am. that is not a real option. 🫶

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🌈 STANDARDS 🌈

Linux. ia64 only, bestie — don't go trying this on your x86 laptop and then act surprised. iykyk. 💜

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🕰️ HISTORY 🕰️

Linux 2.4.18 and 2.5.9. And yes, it's (ia64). She's been around a minute. 🎀

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🔥 SEE ALSO 🔥

• prctl(2)
• PR_GET_FPEMU(2const)

(that second one is the getter — the one who tells you what the bits currently are, if you were wondering 💅)

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mwah 💋 that's the whole page. thanks for reading, bestie — go set some floating-point emulation bits responsibly.

this little love letter came to you from Linux man-pages 6.20, dated 2026-02-08. she's a PR_SET_FPEMU(2const) girl through and through. 🦋✨