io_uring_cq_advance(3)

💖 io_uring_cq_advance(3) — liburing Manual 💖

okay bestie, welcome to the liburing girlies' guide to telling the kernel "yeah I saw that, next" 💅

✨ NAME ✨

io_uring_cq_advance — mark one or more io_uring completion events as consumed

🌸 SYNOPSIS 🌸

#include <liburing.h>

void io_uring_cq_advance(struct io_uring *ring,
                          unsigned nr);

🦋 DESCRIPTION 🦋

so like, io_uring_cq_advance(3) marks nr IO completions belonging to the ring param as consumed. that's it. that's the whole job. no cap. 🎀

here's the vibe: after the caller has submitted a request with io_uring_submit(3), the application can retrieve the completion with io_uring_wait_cqe(3), io_uring_peek_cqe(3), or any of the other CQE retrieval helpers, and then mark it as consumed with io_uring_cqe_seen(3). iconic behavior honestly. ✨

and plot twist — the function io_uring_cqe_seen(3) calls the function io_uring_cq_advance(3). so it's giving "you've been calling it this whole time without knowing." 😭

now listen up because this is the important part 👑: completions must be marked as seen, so their slot can get reused. failure to do so will result in the same completion being returned on the next invocation. that's not a cute little quirk, that's a bug in your app. don't be that girl. 🚫

🎀 RETURN VALUE 🎀

None 💀 — it's a void function, she returns nothing, she just does.

🌈 SEE ALSO 🌈

• io_uring_submit(3)
• io_uring_wait_cqe(3)
• io_uring_peek_cqe(3)
• io_uring_wait_cqes(3)
• io_uring_wait_cqe_timeout(3)
• io_uring_cqe_seen(3)

and that's the whole page bestie 🫶 this one's from liburing-2.1, dated January 25, 2022 — so she's an elder but she's still slaying. go advance those completions, you're literally the main character of your own event loop. periodt. 💜