PR_SET_FPEXC(2const)

✨ PR_SET_FPEXC ✨

okay bestie, so this is PR_SET_FPEXC, and it lives in section 2const of the manual (that's the "constants that go inside prctl(2) calls" corner of the man-pages universe, iykyk 💅). It's a lil' prctl(2) operation and it's genuinely so specific it hurts — it's giving very niche PowerPC excellence.

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🎀 LIBRARY

Standard C library (libc, -lc) — the usual girlies.

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🌸 SYNOPSIS

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

int prctl(PR_SET_FPEXC, unsigned long mode);

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💖 DESCRIPTION

So you're setting the floating-point exception mode to mode, right? And mode has to be one of these iconic little values below. No cap, that's the whole gig. 🦋

• PR_FP_EXC_SW_ENABLE — use FPEXC for FP exception enables.
• PR_FP_EXC_DIV — use FPEXC for floating-point divide by zero.
• PR_FP_EXC_OVF — use FPEXC for floating-point overflow.
• PR_FP_EXC_UND — use FPEXC for floating-point underflow.
• PR_FP_EXC_RES — use FPEXC for floating-point inexact result.
• PR_FP_EXC_INV — use FPEXC for floating-point invalid operation.
• PR_FP_EXC_DISABLED — use FPEXC for FP exceptions disabled.
• PR_FP_EXC_NONRECOV — use FPEXC for async nonrecoverable exception mode.
• PR_FP_EXC_ASYNC — use FPEXC for async recoverable exception mode.
• PR_FP_EXC_PRECISE — use FPEXC for precise exception mode.

like... ten whole options. she's thorough. 🫶

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⭐ RETURN VALUE

• Success? You get 0 back. slay. ✨
• Error? You get -1, and errno gets set to tell you what went wrong. 😭

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💀 ERRORS

• EINVAL — mode is not a valid value. (aka you handed her a mode she does not recognize, and she is not playing that game, periodt.)

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👑 STANDARDS

Linux. And PowerPC only — she does not exist anywhere else, bestie. This is a PowerPC-exclusive main character moment. 🌈

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🧚 HISTORY

Linux 2.4.21, 2.5.32. (PowerPC) — old money, fr fr.

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🔥 SEE ALSO

• prctl(2)
• PR_GET_FPEXC(2const)

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and that's the whole page, babe 💜 this was Linux man-pages 6.20, dated 2026-02-08 — PR_SET_FPEXC(2const), signing off 🎀✨ go forth and set those floating-point exception modes responsibly, mwah 🫶