io_set_callback(3)

✨ io_set_callback(3) ✨

okay bestie, we're in the Linux AIO section of the manual, and today's main character is io_set_callback — the lil helper that hooks your completion callback up to an iocb. it's a <libaio.h> girlie, she's static inline, she's lowkey iconic. let's get into it 💅

🌸 NAME 🌸

io_set_callback — set up the io completion callback function 🎀

🦋 SYNOPSIS 🦋

#include <errno.h>

#include <libaio.h>

static inline void io_set_callback(struct iocb *iocb, io_callback_t cb);

struct iocb {
     void      *data;
     unsigned  key;
     short          aio_lio_opcode;
     short          aio_reqprio;
     int       aio_fildes;
};

typedef void (*io_callback_t)(io_context_t ctx, struct iocb *iocb, long res, long res2);

like yes, that's a whole struct AND a typedef in the synopsis, she's thorough, we respect it 🫶

💖 DESCRIPTION 💖

so here's the tea, bestie: the callback is not done if the caller uses raw events from io_getevents(3). nope, not happening. it only fires with the library helpers. that's the whole vibe. no cap.

⚠️ fr fr — if you're pulling raw events straight out of io_getevents(3), your callback is just not going to run. it's giving ghosted. 🙈

⭐ RETURN VALUES ⭐

None. literally nothing. void behavior, void energy, she returns nothing and that's fine 💀

🌈 ERRORS 🌈

None. no errors, no drama, we love a low-maintenance queen 👑

👑 SEE ALSO 👑

• io(3)
• io_cancel(3)
• io_fsync(3)
• io_getevents(3)
• io_prep_fsync(3)
• io_prep_pread(3)
• io_prep_pwrite(3)
• io_queue_init(3)
• io_queue_release(3)
• io_queue_run(3)
• io_queue_wait(3)
• io_submit(3)
• errno(3)

go read all of them, i'll wait, they're all part of the same friend group 💜

and that's the page!! this one's from the Linux crew, dated 2019-07-23, so yeah she's been serving accurate documentation since way back. mwah, bye bestie 🎀✨💖