AIO_RETURN(3POSIX)

💖 AIO_RETURN 💖

okay bestie, welcome to the POSIX Programmer's Manual — this page lives in section 3POSIX, and it's all about aio_return. Quick heads up tho:

⚠️ This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

like. it might not even exist on ur machine. vibe check first, always. 🫶

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✨ NAME ✨

aio_return — retrieve return status of an asynchronous I/O operation

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🌸 SYNOPSIS 🌸

#include <aio.h>

ssize_t aio_return(struct aiocb *aiocbp);

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🦋 DESCRIPTION 🦋

so the whole point, fr fr: aio_return() shall return the return status associated with the aiocb structure referenced by the aiocbp argument. that return status for an asynchronous I/O operation is literally the value that would be returned by the corresponding read(), write(), or fsync() function call. iconic, right? it's giving "i did the async thing, now gimme the receipts." 🧾

now here's the tea tho — if the error status for the operation is equal to [EINPROGRESS], then the return status for the operation is undefined. not "zero", not "maybe", undefined. do not touch. 💀

and listen, this is the part everyone fumbles: the aio_return() function may be called exactly once to retrieve the return status of a given asynchronous operation. once. that's it. thereafter, if the same aiocb structure is used in a call to aio_return() or aio_error(), an error may be returned. so like, don't be greedy bestie, one grab and done. 🙈

BUT — and this is the redemption arc — when the aiocb structure referred to by aiocbp is used to submit another asynchronous operation, then aio_return() may be successfully used to retrieve the return status of that operation. new operation, new you. slay. 💅

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👑 RETURN VALUE 👑

• If the asynchronous I/O operation has completed, then the return status, as described for read(), write(), and fsync(), shall be returned. 🎉
• If the asynchronous I/O operation has not yet completed, the results of aio_return() are undefined. no cap. don't do it.
• If the aio_return() function fails, it shall return -1 and set errno to indicate the error.

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💅 ERRORS 💅

The aio_return() function may fail if:

• EINVAL — The aiocbp argument does not refer to an asynchronous operation whose return status has not yet been retrieved.

lowkey this is the "u already did this one, girl" error. the status was already retrieved, or it was never a pending async op to begin with. either way, EINVAL says no. 🚫

The following sections are informative.

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🎀 EXAMPLES 🎀

None.

(not me showing up to the examples section with nothing. it's fine. it's minimalism. ✨)

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🌈 APPLICATION USAGE 🌈

None.

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🍓 RATIONALE 🍓

None.

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🧚 FUTURE DIRECTIONS 🧚

None.

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⭐ SEE ALSO ⭐

aio_cancel(), aio_error(), aio_fsync(), aio_read(), aio_write(), close(), exec, exit(), fork(), lio_listio(), lseek(), read()

The Base Definitions volume of POSIX.1‐2017, <aio.h>

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💜 COPYRIGHT 💜

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

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and that's the whole page, bestie!! brought to u by IEEE/The Open Group, 2017 — AIO_RETURN(3POSIX), out. go call aio_return() exactly once and live ur truth. periodt. 💖✨🎀