PR_SVE_GET_VL(2const)

💖 PR_SVE_GET_VL(2const) 💖

okay bestie so this is a page from the Linux man-pages situation (yes the 2const one, we love a const page, very demure) and it's all about asking your thread "hey girl what's your SVE vector length rn" 🦋

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✨ NAME ✨

PR_SVE_GET_VL — get the thread's SVE vector length 💅

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📚 LIBRARY 📚

Standard C library (libc, -lc) — the classic, the icon, the one you already linked 🌸

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🎀 SYNOPSIS 🎀

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

int prctl(PR_SVE_GET_VL);

not me pulling in two headers just to vibe check a vector length 😭 but that's the gig, PR_* constants live in linux/prctl.h and the prctl() call itself lives in sys/prctl.h. slay.

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💫 DESCRIPTION 💫

So like, this op gets the thread's current SVE vector length configuration. That's it, that's the whole job, and it eats. 👑

This operation returns a nonnegative value that describes the current configuration. And the way that value is built?? It's giving bitfield:

• The bits corresponding to PR_SVE_VL_LEN_MASK contain the currently configured vector length in bytes. 📏
• The bit corresponding to PR_SVE_VL_INHERIT tells you whether the vector length will be inherited across execve(2). 🧬

one number, two secrets, main character energy fr fr.

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🔥 RETURN VALUE 🔥

On success, PR_SVE_GET_VL returns the nonnegative values described above (yes the mask bits, the whole little package 💖).

On error, -1 is returned, and errno is set to indicate the error. classic.

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💀 ERRORS 💀

• EINVAL — SVE is not available on this platform. aka you asked and the platform said "girl I don't do SVE" 🙈

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🌈 STANDARDS 🌈

Linux. arm64 only. 💅 so if you're not on arm64, this is not your moment, no cap.

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⭐ HISTORY ⭐

Linux 4.15 (arm64). a little vintage, a little legendary, we respect the elders 🫶

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⚠️ CAVEATS ⚠️

There is no way to determine whether there is a pending vector length change that has not yet taken effect. 😭

like literally there's just no way to know if a change is queued up and hasn't landed yet. that information? not available. gone. we simply don't have it. don't go looking, bestie, it's not there.

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👀 SEE ALSO 👀

• prctl(2)
• PR_SVE_SET_VL(2const) — the setter, the other half of this duo, the one who actually changes stuff 💅

For more information, see the kernel source file Documentation/arch/arm64/sve.rst. 🍓 go read it, iykyk.

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and that's the page!! this came to you from Linux man-pages 6.20, dated 2026-02-08 — mwah, kiss the maintainers, they ate 💖✨🎀