io_uring_cqe_nr(3)

📦 version 2.15, in alpine 3.24, arch rolling, nixpkgs unstable, ubuntu resolute, ubuntu stonking

💖 io_uring_cqe_nr — bestie edition 💖

okay so this one is from the liburing manual, and honestly? it's short, it's sweet, and it's lowkey essential if you're out here living that mixed-CQE life. no cap. 🦋

✨ NAME ✨

io_uring_cqe_nr — returns the number of CQ ring slots that a CQE has eaten. that's it, that's the whole job. it's giving "small but mighty" 💅

🌸 SYNOPSIS 🌸

#include <liburing.h>

unsigned io_uring_cqe_nr(const struct io_uring_cqe *cqe);

🎀 DESCRIPTION 🎀

so, io_uring_cqe_nr(3) tells you how many CQ ring slots your cqe has consumed. like, how much room did this little guy take up in the ring? 🫶

here's the tea:

  • for normal 16-byte CQEs, it returns 1. one slot. a single serving. perfectly reasonable. ✨
  • for 32-byte CQEs, which happen when IORING_CQE_F_32 is set in the CQE flags, it returns 2. two slots. it's an overachiever, we love that for it. 👑

and why do you care, bestie? because when you're advancing the CQ ring with io_uring_cq_advance(3) on rings that use IORING_SETUP_CQE_MIXED — where both 16-byte and 32-byte CQEs can show up in the same ring, chaos incarnate — you can't just assume every CQE takes one slot. that's a trap. this function is your vibe check. it tells you exactly how far to advance so you don't skip past a CQE or trip over your own ring. main character energy fr fr 😭

not me almost advancing by one when a 32-byte CQE was sitting there the whole time 💀

💜 RETURN VALUE 💜

  • returns 1 for normal CQEs
  • returns 2 for 32-byte CQEs

that's it. two possible answers. no in-between, no drama, no edge cases beyond that. periodt. 💅

🌈 SEE ALSO 🌈

kisses, bestie 🫶 this page is from liburing-2.12, dated January 18, 2025, and that's the whole manual. go advance your ring correctly, i'm so proud of you 🎀💖

📦 where this page comes from