atomic64_fetch_inc(9)

📦 version 7.3.1, in nixpkgs unstable

💅 atomic64_fetch_inc(9) — from the Kernel API Manual ✨

okay so bestie, we're in the Kernel API Manual, section 9, and today's main character is atomic64_fetch_inc. she's a little function with a big job and honestly? she ate. 🎀

🌸 NAME 🌸

atomic64_fetch_inc — atomic increment with full ordering 💖

like, she bumps your number up by one, atomically, and she does not cut corners on ordering. periodt.

✨ SYNOPSIS ✨

s64 atomic64_fetch_inc (atomic64_t *v );

that's it. that's the whole vibe check. one arg, returns an s64, slay. 🦋

🫶 ARGUMENTS 🫶

  • v — pointer to atomic64_t. yeah. that's the whole description. she's a pointer, she points at an atomic64_t, we love her for it. 👑

🔥 DESCRIPTION 🔥

Atomically updates v to (v + 1) with full ordering.

no cap, that's the whole thing: the value goes up by exactly one, nobody can catch her mid-update, and the ordering is full — not relaxed, not acquire, not release, full. main character energy fr fr. 💅

⚠️ okay so important safety moment: it is unsafe to use in noinstr code. if you're in noinstr land, use raw_atomic64_fetch_inc there instead. don't be the person who ignores this, i'm literally begging. 😭

⭐ RETURN ⭐

The original value of v. 🍓

like — she increments it, but what she hands back to you is what it was before the bump. the before picture. the pre-slime. iconic behaviour honestly.

🌈 SEE ALSO 🌈

okay so this list is a whole journey, buckle up bestie. also heads up: the kernel file is ./include/linux/atomic/atomic-instrumented.h — that's where all this lives. 🧚

the atomic_* girlies (32-bit era):

🦋 the atomic64_* fam (our girl's actual household) 🦋

💜 the atomic_long_* cousins, still iconic 💜

🎀 sign-off 🎀

that's the whole page bestie, and yes it really did come from the file ./include/linux/atomic, dated October 2026, and the page itself is atomic64_fetch_inc(9). go forth, increment atomically, respect the noinstr warning, and remember — full ordering or nothing. mwah. 💋 slay 🌈✨

📦 where this page comes from