is_aligned(9)

💅 is_aligned — Kernel API Manual energy ✨

okay so this is the is_aligned page from the Kernel API Manual, and it's lowkey a vibe check for pointers and sizes. Let's get into it, bestie 🫶

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🌸 NAME 🌸

is_aligned — is this pointer & size okay for word-wide copying?

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✨ SYNOPSIS ✨

bool is_aligned (const void *base , size_t size , unsigned char align );

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🎀 ARGUMENTS 🎀

• base — pointer to data
• size — size of each element
• align — required alignment (typically 4 or 8)

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💖 DESCRIPTION 💖

Returns true if elements can be copied using word loads and stores. The size must be a multiple of the alignment, and — fr fr, this is the exact wording — the base address must be if we do not have CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS.

For some reason, gcc doesn't know to optimize if (a & mask || b & mask) to if ((a | b) & mask), so we do that by hand. iconic little workaround, ngl 💅

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🦋 SEE ALSO 🦋

• Kernel file ./lib/sort.c
• swap_words_32(9)
• swap_words_64(9)
• swap_bytes(9)
• parent(9)
• sort_r(9)
• sort_r_nonatomic(9)

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🫶 cute little sign-off: source/version is ./lib, dated October 2026, and the page is is_aligned(9) — bye bestie, go align something slay 💖✨