PR_CAP_AMBIENT(2const)

💖 PR_CAP_AMBIENT 💖

okay bestie, so this one lives in section 2const of the manual pages — it's a PR_CAP_AMBIENT thing, and it's all about the ambient capability set of the calling thread. Yep. Reading it, changing it, the whole vibe. ✨

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📖 NAME

PR_CAP_AMBIENT — read or change the ambient capability set of the calling thread 🫶

📚 LIBRARY

Standard C library (libc, -lc) 💅

✨ SYNOPSIS

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

int prctl(PR_CAP_AMBIENT, long op, ...);

like yes it's a prctl() call, she's fancy, she takes an op and then a lil ... because she's mysterious 🌸

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🦋 DESCRIPTION

So this reads or changes the ambient capability set of the calling thread, and which one it does depends entirely on the value of op. And op has to be one of these, no exceptions, no substitutions:

• PR_CAP_AMBIENT_RAISE 🎀
• PR_CAP_AMBIENT_LOWER 🎀
• PR_CAP_AMBIENT_IS_SET 🎀
• PR_CAP_AMBIENT_CLEAR_ALL 🎀

that's the whole list, bestie, that's the menu 🌈

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👑 RETURN VALUE

On success, a nonnegative value comes back. Iconic. On error, you get -1, and errno gets set to tell you what went wrong 😭

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💀 ERRORS

• EINVAL — op is not a valid value. like girl, that's not one of the four, try again 🙈

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🌟 VERSIONS

If you want the glow-up version of all this, there's higher-level interfaces layered on top of the operations above, and they live in the libcap(3) library, shaped like:

• cap_get_ambient(3)
• cap_set_ambient(3)
• cap_reset_ambient(3)

obsessed, honestly 💜

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⭐ STANDARDS

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

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🕰️ HISTORY

Linux 4.3. she's been around a minute 💖

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🔥 SEE ALSO

• prctl(2)
• PR_CAP_AMBIENT_RAISE(2const)
• PR_CAP_AMBIENT_LOWER(2const)
• PR_CAP_AMBIENT_IS_SET(2const)
• PR_CAP_AMBIENT_CLEAR_ALL(2const)
• libcap(3)
• cap_get_ambient(3)
• cap_set_ambient(3)
• cap_reset_ambient(3)

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and that's the whole page bestie, go read those capabilities, slay 💅✨

okay mwah, this was Linux man-pages 6.20, dated 2026-02-08 — love her, no cap 🫶💖