wrapping_assign_sub(9)

💅 wrapping_assign_sub(9) — like, the Kernel API Manual, but make it make sense ✨

okay so bestie, welcome to wrapping_assign_sub(9), straight out of the Kernel API Manual. no cap, this one's a tiny little legend and you're gonna love her 🫶

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🌸 NAME 🌸

wrapping_assign_sub — intentionally perform a wrapping decrement assign 💅 (yes, intentionally. she knows exactly what she's doing.)

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✨ SYNOPSIS ✨

wrapping_assign_sub (var , offset );

that's it. that's the whole vibe. two args, zero drama 🎀

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🦋 ARGUMENTS 🦋

• var — the variable that's getting decremented. she's the main character here 👑
• offset — how much you're subtracting from her. the amount, the whole amount, nothing but the amount 🍓

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🔥 DESCRIPTION 🔥

so what she does is: decrements var by offset, with wrap-around. literally that's the assignment. returns the resulting value of var. 💫

and the iconic part? will not trip any wrap-around sanitizers. not a single one. she said "i'm not setting off any alarms today" and she meant it 🙈

also, to be super clear since the manpage says it twice (she's thorough, we love her): returns the new value of var. ⭐

like… it's giving "small function, big confidence." one job, done flawlessly, no sanitizer crying in the group chat 😭💖

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🧚 SEE ALSO 🧚

all her besties live in the kernel file ./include/linux/overflow.h and honestly the whole friend group is iconic 🌈:

• check_add_overflow(9)
• wrapping_add(9)
• wrapping_assign_add(9)
• check_sub_overflow(9)
• wrapping_sub(9)
• check_mul_overflow(9)
• wrapping_mul(9)
• check_shl_overflow(9)
• overflows_type(9)
• range_overflows(9)
• range_overflows_t(9)
• range_end_overflows(9)
• range_end_overflows_t(9)
• castable_to_type(9)
• size_mul(9)
• size_add(9)
• size_sub(9)
• array_size(9)
• array3_size(9)
• flex_array_size(9)
• struct_size(9)
• struct_size_t(9)
• struct_offset(9)
• __DEFINE_FLEX(9)
• _DEFINE_FLEX(9)
• DEFINE_RAW_FLEX(9)
• DEFINE_FLEX(9)
• STACK_FLEX_ARRAY_SIZE(9)
• typeof_flex_counter(9)
• overflows_flex_counter_type(9)
• __set_flex_counter(9)

go read them all, iykwim 💀💜

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and that's the whole page, bestie!! 🎀 this little gem comes to you from ./include/linux, dated October 2026 — go off, queen, slay the wrap-around, periodt 💅✨🌸