local_dec_and_test(9)

💅 local_dec_and_test(9) 💅

okay so welcome to the Kernel API Manual, bestie — today's main character is local_dec_and_test, and honestly? she's a little icon. let's get into it ✨

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🌸 NAME 🌸

local_dec_and_test — decrement and test. that's it, that's the whole vibe. she takes one away and then does a lil vibe check on the result 🎀

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✨ SYNOPSIS ✨

bool local_dec_and_test (local_t *l );

no cap, that's the entire signature. short and slay 💅

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🦋 ARGUMENTS 🦋

• l — a pointer to type local_t. yeah she wants the address, not the thing itself. hand her the pointer and she's good 🫶

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🔥 DESCRIPTION 🔥

so here's the tea: local_dec_and_test atomically decrements l by 1, and then it's like, ok bestie, let's check — it returns true if the result is 0, and false for all other cases. literally all of them. no exceptions, no in-between, no "it depends" energy 😭

key word there is atomically — the whole decrement-and-check happens as one indivisible moment, so nobody's gonna sneak in mid-decrement and mess with your math. icon behavior fr fr 👑

lowkey a reminder so you don't get caught out: true means the thing hit exactly 0. anything else on the number line gives you false. that's the entire contract, don't go reading extra lore into it 💀

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⭐ SEE ALSO ⭐

• kernel file ./arch/x86/include/asm/local.h
• local_sub_and_test(9)
• local_inc_and_test(9)
• local_add_negative(9)
• local_add_return(9)
• local_add_unless(9)

the whole local_* friend group really said "we're a package deal" 🌈 go say hi to the rest of them, they're all linked from ./arch/x86/include/asm/local.h and they ate 💖

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and that's the page! 🧚 this little drop came from ./arch/x86/include/asm, dated October 2026 — so yeah, she's fresh, she's documented, and she's absolutely serving kernel-internals realness. mwah, go decrement something responsibly 💜🌸

local_dec_and_test(9) 🎀 — bye bestie!! 🫶