idr_is_empty(9)

💅 idr_is_empty(9) — the Kernel API Manual, bestie edition

okay so you found the page for idr_is_empty, which lives in the Kernel API Manual and is literally just one tiny question: is this thing empty or not? let's get into it 🎀

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✨ NAME ✨

idr_is_empty — Are there any IDs allocated? 👀

like. that's the whole vibe check. we're asking an IDR whether anything's been handed out yet.

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🌸 SYNOPSIS 🌸

bool idr_is_empty (const struct idr *idr );

bestie it returns a bool and takes one pointer, that's it, no drama, no cap 💅

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🦋 ARGUMENTS 🦋

• idr — the IDR handle, aka the little guy you're interrogating. that's the one and only argument, she's low maintenance ✨

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🔥 RETURN 🔥

true if any IDs have been allocated from this IDR.

ok so yes, that's literally what the page says — true when IDs have been allocated. I'm not gonna editorialize on the naming, I'm just the messenger, and the messenger is keeping the wording exactly as documented 🙈💀

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🌈 SEE ALSO 🌈

all the siblings and cousins, in the order the page gives them, and yes I'm listing every single one because we don't skip ✨:

• Kernel file ./include/linux/idr.h
• IDR_INIT(9)
• DEFINE_IDR(9)
• idr_get_cursor(9)
• idr_set_cursor(9)
• idr sync(9)
• idr_init_base(9)
• idr_init(9)
• idr_preload_end(9)
• idr_for_each_entry(9)
• idr_for_each_entry_ul(9)
• idr_for_each_entry_continue(9)
• idr_for_each_entry_continue_ul(9)
• ida_alloc(9)
• ida_alloc_min(9)
• ida_alloc_max(9)

(that idr sync(9) with the space? yeah, that's how it's written on the page, so that's how I'm writing it. character for character, periodt 💜)

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mwah, that's the whole page 🫶 this cutie comes from ./include/linux and it's dated October 2026 — go forth and check your IDRs, bestie, you're gonna slay 💖