AIO_WAITCOMPLETE(2)

💅 AIO_WAITCOMPLETE(2) 💅

ok so bestie, you're looking at the System Calls Manual — this is the page for aio_waitcomplete, and honestly? It's a little baddie. Let's get into it 🎀

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✨ NAME ✨

aio_waitcomplete — wait for the next completion of an aio request 🫶

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📚 LIBRARY 📚

Standard C Library (libc, -lc) — she's built in, no extra shopping required 💖

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🧚 SYNOPSIS 🧚

#include <aio.h>

ssize_t
aio_waitcomplete(struct aiocb **iocbp, struct timespec *timeout);

That's the whole vibe. Two args, one return, zero drama (mostly). ⭐

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🌸 DESCRIPTION 🌸

So aio_waitcomplete() is a system call that waits for the completion of an asynchronous I/O request. It's giving "I'll be right there, just let me finish this." ⏳

The moment that request completes, aio_waitcomplete() returns the result of the function and sets iocbp to point to the structure associated with the original request. And if an asynchronous I/O request already completed before you even called aio_waitcomplete()? It returns immediately with that completed request — no waiting, instant slay 💅

Now if timeout is a non-NULL pointer, it specifies a maximum interval to wait for an asynchronous I/O request to complete. If timeout is a NULL pointer, aio_waitcomplete() waits indefinitely — that's main character commitment, no cap. 🕰️

And to effect a poll, the timeout argument should be non-NULL, pointing to a zero-valued timeval structure. Lowkey genius.

🚨 Important bestie moment: the aio_waitcomplete() system call also serves the function of aio_return(), thus aio_return() should not be called for the control block returned in iocbp. Do not double-dip, I'm begging 🙈

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💜 RETURN VALUES 💜

If an asynchronous I/O request has completed, iocbp is set to point to the control block passed with the original request, and the status is returned as described in read(2), write(2), or fsync(2) — so go read those pages, iykyk 🌈

On failure, aio_waitcomplete() returns -1, sets iocbp to NULL, and sets errno to indicate the error condition. Sad girl hours 😭

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🔥 ERRORS 🔥

The aio_waitcomplete() system call fails if:

• [EAGAIN] — The process has not yet called aio_read() or aio_write(). Like bestie… you gotta start something before you can finish it 💀
• [EINTR] — A signal was delivered before the timeout expired and before any asynchronous I/O requests completed. Interrupted, respectfully 🫶
• [EINVAL] — The specified time limit is invalid. That clock is not clocking 🕰️
• [EWOULDBLOCK]
• [EINPROGRESS] — The specified time limit expired before any asynchronous I/O requests completed. Time ran out, nothing finished, it's giving waiting-room energy 🎀

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👑 SEE ALSO 👑

aio_cancel(2), aio_error(2), aio_read(2), aio_return(2), aio_suspend(2), aio_write(2), fsync(2), read(2), write(2), aio(4) — the whole friend group, go say hi 💖

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⭐ STANDARDS ⭐

The aio_waitcomplete() system call is a FreeBSD-specific extension. Exclusive. FreeBSD-only. We don't gatekeep but also we kinda do 💅

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🦋 HISTORY 🦋

The aio_waitcomplete() system call first appeared in FreeBSD 4.0. Iconic since day one, fr fr 👑

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🍓 AUTHORS 🍓

The aio_waitcomplete() system call and this manual page were written by Christopher M Sedore <cmsedore@maxwell.syr.edu>. We love a legend who documents their own work, no cap 🔥

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and that's the whole page bestie! this one's from the Debian fam, dated March 27, 2025, and it's for AIO_WAITCOMPLETE(2). go forth and await your completions 💖✨🎀