cpumask_first_andnot(9)

📦 version 7.3.1, in nixpkgs unstable

💅 cpumask_first_andnot — bestie's guide to cpumask_first_andnot(9)

okay so first things first, the manual name is cpumask_first_andnot and this whole thing lives in the Kernel API Manual, section 9. buckle up 🎀

✨ NAME ✨

cpumask_first_andnot — returns the very first cpu from *srcp1 & ~*srcp2, no cap 💅

like, it's giving "who's in the first mask but NOT in the second mask, and who's first in line" energy. iconic.

🌸 SYNOPSIS 🌸

unsigned int cpumask_first_andnot (const struct cpumask *srcp1 , const
       struct cpumask *srcp2 );

that's the whole signature, take it in, it's literally right there 🫶

🦋 ARGUMENTS 🦋

  • srcp1 — the first input. the main character mask, if you will 👑
  • srcp2 — the second input. the other one we're subtracting from the vibe 💀

⭐ RETURN ⭐

>= nr_cpu_ids if no such cpu found. 👀

so like, if it comes back with a number that's >= nr_cpu_ids, that's your sign that nothing matched — it's not a real cpu id, it's the "nope, didn't find one" of it all 😭

🌈 SEE ALSO 🌈

everything's in the kernel file ./include/linux/cpumask.h — and honestly the friend group here is HUGE, so let's go 🧚

fr fr that's a lot of friends. read them, love them, they're all in ./include/linux/cpumask.h 💖

and that's the page!! mwah 🫶 this cutie is from ./include/linux, dated October 2026 — so note the date, bestie, and slay your kernel dev era ⭐🌸💜

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