io_uring_register_ifq(3)

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

💖 io_uring_register_ifq — the liburing manual, bestie edition 💖

okay so you're in the liburing Manual and this is the page for io_uring_register_ifq(3) 🎀

✨ NAME ✨

io_uring_register_ifq — register a zero-copy receive interface queue 🦋

🌸 SYNOPSIS 🌸

#include <liburing.h>

int io_uring_register_ifq(struct io_uring *ring,
                          struct io_uring_zcrx_ifq_reg *reg);

💅 DESCRIPTION 💅

so io_uring_register_ifq(3) registers a zero-copy receive interface queue with the io_uring instance you pass in as ring. and why do we care? because zero-copy receive lets the kernel drop incoming network data straight into memory your app provided — no copying, none, zero, it's giving efficiency ✨

the reg argument is a pointer to a struct io_uring_zcrx_ifq_reg, and it's basically the little description card for the interface queue you wanna register 📝 if you wanna know about the IORING_REGISTER_ZCRX_IFQ operation and all the struct fields, go read io_uring_register(2), it's all in there.

🚨 ok now the rules, and these are NOT optional bestie: - your io_uring ring must have been created with IORING_SETUP_DEFER_TASKRUN and either IORING_SETUP_CQE32 or IORING_SETUP_CQE_MIXED flags set. both. the defer one and one of the other two. no shortcuts 💀 - the caller must have the CAP_NET_ADMIN capability. like, actually. 👑

👑 RETURN VALUE 👑

returns 0 on success 🎉 on error, you get a negative errno value back. sad but informative 😭

🫶 SEE ALSO 🫶

ok that's the whole page, you ate it 💅✨ this was liburing-2.10, dated January 18, 2025 — go register something iconic bestie, iykyk 🦋🌸🎀

📦 where this page comes from