PR_SET_VMA(2const)

💖 PR_SET_VMA 💖

okay bestie, welcome to PR_SET_VMA, a.k.a. the little prctl(2) operation that lets you slap an attribute onto a virtual memory area. that's literally the whole job. she sets attributes. she's an icon, she's a legend, and she is the moment ✨

this page lives in section 2const of the manual (iykyk), and if you need more context on the parent function you'll wanna peek at prctl(2) — we link it down in SEE ALSO, no gatekeeping here 🫶

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🌸 LIBRARY 🌸

Standard C library (libc, -lc). yes ma'am, the classic. nothing exotic.

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✨ SYNOPSIS ✨

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

int prctl(PR_SET_VMA, long attr, unsigned long addr, unsigned long size,
          const char *_Nullable val);

not me including both headers… you do actually need both, so don't skip one 🙈

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💅 DESCRIPTION 💅

so here's the vibe: we set an attribute — that's the one named in attr — for virtual memory areas that start at the address in addr and span for size. and val is the value of the attribute you're setting. that's the trio. addr, size, val. slay 🔥

⚠️ heads up bestie: slapping an attribute onto a virtual memory area might stop it from getting merged with adjacent virtual memory areas, because that attribute's value is now different. so like… she's special now, she can't just merge into the crowd 💀

Currently, attr must be one of:

• PR_SET_VMA_ANON_NAME — this one sets a name for anonymous virtual memory areas, which is lowkey the cutest feature here 🎀 val should be a pointer to a null-terminated string containing the name. the name length, including the null byte, cannot exceed 80 bytes. and if val is NULL, the name of the appropriate anonymous virtual memory areas gets reset. as for the name itself, it can contain only printable ascii characters (that's isprint(3)) — except '[', ']', '\', '$', and '`'. yeah. those five are banned from the group chat 🚫

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👑 RETURN VALUE 👑

• success? you get 0. periodt.
• error? you get -1, and errno gets set to tell you what went wrong.

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😭 ERRORS 😭

• EINVAL — attr is not a valid attribute. girl, that's not a real attribute 💀
• EINVAL — addr is an invalid address. that address is not it fr fr.

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🌈 STANDARDS 🌈

Linux. that's it, that's the standard. 🐧

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🦋 HISTORY 🦋

Linux 5.17. so she's a relatively recent queen, born in 2022, already glowing ✨

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💜 SEE ALSO 💜

• prctl(2) — the main character of the whole family, go read her

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okay that's the whole page bestie, you're fully caught up, go set some VMAs 🫶

this was brought to you by Linux man-pages 6.20, dated 2026-02-08 — yes the date is in the future, don't think about it, just vibe 🌸💖✨