nvme_get_nsid(2)

✨ nvme_get_nsid ✨

okay so bestie, welcome to the libnvme API manual 💖 today's main character is nvme_get_nsid(2) — the little function that goes "hey, what's the namespace ID on this file descriptor?" and the kernel is like "ugh, fine, it's in my return value for some reason" 😭

Not me being obsessed with a getter, but here we are. Let's get into it 🫶

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🌸 NAME 🌸

nvme_get_nsid — Retrieve the NSID from a namespace file descriptor

Like. The whole vibe. You hand it a namespace fd and it tells you the NSID. That's it. That's the girl. 💅

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🎀 SYNOPSIS 🎀

int nvme_get_nsid (int fd , __u32 *nsid );

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🦋 ARGUMENTS 🦋

• fd — File descriptor of nvme namespace. fr fr, just the fd, the plain little int.
• nsid — User pointer to namespace id. you give it a place to write the answer, __u32 *, iconic.

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💜 DESCRIPTION 💜

Okay so listen up, this is lowkey important 👑

This should only be sent to namespace handles, not to controllers. Like, do not do that. Read the room. 🚫

Here's the messy part: the kernel's interface returns the nsid as the return value. And ngl, that's… unfortunate. 😭 Why? Because on many architectures, there's literally no way to tell a namespace id that's greater than 0x80000000 apart from a negative error number. Same bits, different meanings, absolutely no way to distinguish them. It's giving chaos. It's giving ambiguous. It's giving "who designed this" energy. 💀

So yeah: big NSIDs + negative errnos = indistinguishable on those architectures. Not a bug in your code, just the universe being like that. Keep it in mind, iykyk.

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🌈 RETURN 🌈

• 0 if nsid was set successfully 🥳
• -1 with errno set otherwise 😔

periodt.

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💖 SEE ALSO 💖

hmm, no SEE ALSO on this one bestie, she's a standalone queen. 👑

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and that's the whole page, slay ✨

this little cutie comes to you straight from the libnvme API manual, dated July 2026, and yeah — nvme_get_nsid is also her own SEE ALSO, because she's self-referential like that 💅 mwah, go forth and get those NSIDs responsibly 🍓🧚💜