atomic_xchg(9)

📦 version 7.3.1, in nixpkgs unstable

💅 atomic_xchg(9) — Kernel API Manual, but make it make sense

okay so real talk, bestie — you found yourself in the atomic_xchg(9) page of the Kernel API Manual, and it's genuinely one of the shortest baddies in the whole atomic family, so let's go ✨

🌸 NAME 🌸

atomic_xchg — atomic exchange with full ordering 🎀

like, it swaps a value in and gives you back the old one, and it does it atomically, no cap 👑

🦋 SYNOPSIS 🦋

int atomic_xchg (atomic_t *v , int new );

💜 ARGUMENTS 💜

  • v — pointer to atomic_t. this is your victim, the thing getting swapped 🫶
  • new — int value to assign. this is the glow-up going in ✨

🔥 DESCRIPTION 🔥

Atomically updates v to new with full ordering.

that's it. that's the whole thing. it's giving "short and powerful" 💅 the swap happens as one indivisible unit, and it's got full ordering, so the memory barriers are already handled for you, you don't gotta do a thing 🧚

🚨 unsafe alert 🚨 — this one is unsafe to use in noinstr code; use raw_atomic_xchg there instead. like, do not try it, i'm begging 😭

👑 RETURN 👑

The original value of v. 🌈

so you hand over the new value, and the kernel hands back what was there before — iconic exchange behaviour, mutual, respectful, consensual 🎀

⭐ SEE ALSO ⭐

bestie there are so many of these, grab a snack 🍓 — here's the whole atomic cinematic universe, all (9) sections, all present and accounted for:

atomic_* — the classics 🦋

atomic64_* — the 64-bit edition 💀

atomic_long_* — long boi era 🌈

📁 kernel file: ./include/linux/atomic/atomic-instrumented.h — that's the one that declares this whole crew, iykyk 🧚

and that's the page, bestie 💖 ok bye, go swap something atomically, you're gonna slay ✨

source ./include/linux/atomic · dated October 2026 · page atomic_xchg(9) — mwah, catch you in the next manpage 💅🎀

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