xxh64(9)

✨ xxh64(9) — the Kernel API Manual glow-up ✨

okay so bestie, welcome to the Kernel API Manual entry for xxh64 💅 this is the 64-bit hash girlie and she is literally here to calculate the 64-bit hash of your input with a given seed. no cap.

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🌸 NAME 🌸

xxh64 — calculate the 64-bit hash of the input with a given seed 🎀

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🦋 SYNOPSIS 🦋

uint64_t xxh64 (const void *input , size_t length , uint64_t seed );

like, that's the whole vibe. three args, one uint64_t coming back at you 💖

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🍓 ARGUMENTS 🍓

• input — the data to hash. give her the goods, bestie 🫶
• length — the length of the data to hash. she needs to know how much of the goods to look at ✨
• seed — the seed can be used to alter the result predictably. yes, predictably, it's giving controlled chaos 💅

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🔥 DESCRIPTION 🔥

so here's the tea: this function runs 2x faster on 64-bit systems, but slower on 32-bit systems. highkey important to know before you go around hashing things on your vintage 32-bit machine 😭 it's not a vibe check fail, it's just the way that it is.

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⭐ RETURN ⭐

the 64-bit hash of the data. that's it, that's the reward 👑 she ate and left no crumbs.

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💜 SEE ALSO 💜

• Kernel file ./include/linux/xxhash.h
• xxh32(9)
• xxhash(9)
• struct xxh64_state(9)
• xxh64_reset(9)
• xxh64_update(9)
• xxh64_digest(9)

go read the whole family, iykyk 🌈

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fr fr bestie, don't @ me if you skip the SEE ALSO section — those girls are important 💀

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and that's the page, mwah 💋 this iconic little manual came to you from ./include/linux, dated October 2026, and it's filed under xxh64(9) — periodt. 🧚💖