atomic_long_xchg_acquire(9)

📦 version 7.3.1, in nixpkgs unstable

💖 NAME 💖

atomic_long_xchg_acquire — bestie, it's an atomic exchange, and it comes with acquire ordering 💅

Okay so real quick, this is a page from the Kernel API Manual, and the star of the show is atomic_long_xchg_acquire. It swaps a long in atomically, and the ordering vibes are acquire. That's the whole personality. Slay.

✨ SYNOPSIS ✨

long atomic_long_xchg_acquire (atomic_long_t *v , long new );

Like yes, that's literally it. Two arguments, one long coming back at you 🫶

🎀 ARGUMENTS 🎀

  • v — pointer to atomic_long_t. It's giving "where the value lives" energy.
  • new — the long value to assign. This is the new main character of *v.

🦋 DESCRIPTION 🦋

So here's the tea: it atomically updates v to new, and it does it with acquire ordering. Atomic ✨ ordering ✨ both, no cap.

🚨 Real talk though: it's unsafe to use in noinstr code. If you're in there, use raw_atomic_long_xchg_acquire instead. Not a suggestion, it's the rule, iykyk 💀

🌸 RETURN 🌸

It returns the original value of v — i.e. what was chilling in there before you swapped it. The way that it hands you the old value and the new one is already in place… iconic behavior honestly 👑

💜 SEE ALSO 💜

Kernel file: ./include/linux/atomic/atomic-instrumented.h — that's where the lore lives 📖

And now the friend group. Genuinely huge roster, but every single one of them is here because we don't do left-outs in this house 🫶

The atomic_* girlies:

The atomic64_* girlies:

The atomic_long_* girlies (our homegirl's family 🥹):

That's the whole page bestie, no notes, go forth and exchange atomically 💜 Source file is ./include/linux/atomic, and this cutie is dated October 2026 — catch you in the next atomic_long_xchg_acquire(9) era 🦋✨

📦 where this page comes from