uf_union(9)

💖 uf_union — the "let's be friends" function 💖

okay so quick vibe check: this is uf_union(9) from the Kernel API Manual, and no cap it's one of the most useful little functions in the whole kernel friend group. it's literally a matchmaker for sets 🫶

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✨ NAME ✨

uf_union — merge two sets, using union by rank 💅

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🎀 SYNOPSIS 🎀

void uf_union (struct uf_node *node1 , struct uf_node *node2 );

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🌸 ARGUMENTS 🌸

• node1 — the first node 🥇
• node2 — the second node 🥈

like, they're just two nodes, bestie. two little guys about to become one big friend group.

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🦋 DESCRIPTION 🦋

okay so here's the tea ☕: this function merges the sets containing node1 and node2, by comparing the ranks to keep the tree balanced.

that's it. that's the whole thing. it literally does a rank comparison so the tree doesn't turn into a sad little stick, and then boom 💥 — the two sets are one set now. main character energy for ur disjoint-set forest, fr fr. balance is the vibe check and this function passes it every time 🌈

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👑 SEE ALSO 👑

• Kernel file ./lib/union_find.c
• uf_find(9)

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that's the whole page, bestie — go union some sets and slay ✨

signing off with love from the ./lib girlies, October 2026 🎀💜