IS_ERR(9)

💅 IS_ERR (section 9, Kernel API Manual)

okay bestie, gather round, because this one is short but it is load-bearing 🫶

✨ NAME ✨

IS_ERR — the little macro that tells you whether a pointer is actually an error pointer. That's it. That's the whole job. And she does it flawlessly. 👑

🌸 SYNOPSIS 🌸

bool IS_ERR (__force const void *ptr );

like yes, that's genuinely all the syntax. no extra args, no funny business, just vibes and a bool. ✨

🎀 ARGUMENTS 🎀

• ptr — the pointer you want to check. the one you're side-eyeing. the one you're not sure about. hand her over and let IS_ERR do the vibe check. 🙈

⭐ RETURN ⭐

• true — if ptr is an error pointer. she's an error, girlie. 😭
• false — otherwise. she's fine. false alarm. carry on. 💖

no cap, this is a two-outcome situation and both outcomes are literally in the docs, so don't go expecting a third one. that's the whole return story. 💀

🦋 SEE ALSO 🦋

• Kernel file ./include/linux/err.h — the home base, the mothership, where all of this lives
• IS_ERR_VALUE(9)
• ERR_PTR(9)
• INIT_ERR_PTR(9)
• PTR_ERR(9)
• IS_ERR_OR_NULL(9)
• ERR_CAST(9)
• PTR_ERR_OR_ZERO(9)

like, the whole error-pointer friend group 💜 go read them, they're all serving their own purpose and they all ate. 🔥

and that's the page, bestie — straight from ./include/linux, dated October 2026, living under the IS_ERR(9) name in the Kernel API Manual. mwah 💅🎀🌈