local_sub_and_test(9)

💅 local_sub_and_test(9) — the Kernel API Manual glow-up 🦋

okay so bestie, welcome to the local_sub_and_test(9) page ✨ this one lives in the Kernel API Manual and it's honestly such a little icon — smol function, big main character energy 👑

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✨ NAME ✨

local_sub_and_test — literally subtracts a value from a variable and then tests the result, no cap 🎀

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🌸 SYNOPSIS 🌸

bool local_sub_and_test (long i , local_t *l );

that's it. that's the whole vibe check. 🫶

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💖 ARGUMENTS 💖

• i — the integer value you're subtracting. this is the amount getting yeeted out of the variable 🍓
• l — a pointer to type local_t. this is the variable doing the receiving (well, the un-receiving, since we're subtracting 🙈)

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🔥 DESCRIPTION 🔥

so what does it actually do? it atomically subtracts i from l — atomically meaning no one else can sneak in and mess with it mid-operation, it's giving locked-in, one-and-done, absolutely unbothered behavior 💅

then it checks the result and returns true if the result is zero, or false for all other cases. that's the "and_test" part, babes — the subtraction happens, the answer gets vibe-checked, and you get a lil bool back 🌈

no cap, that's the entire function. iconic, honestly. ⭐

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🦋 SEE ALSO 🦋

if you're obsessed with this one (and why wouldn't you be 👑), go check out the kernel file ./arch/x86/include/asm/local.h and its besties:

• local_dec_and_test(9)
• local_inc_and_test(9)
• local_add_negative(9)
• local_add_return(9)
• local_add_unless(9)

fr fr, they're all in the same friend group 🫶✨

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and that's the whole page, bestie! 💜 this little masterpiece comes to you from ./arch/x86/include/asm, dated October 2026, and it's filed under local_sub_and_test(9). go forth and subtract atomically 🧚‍♀️🎀