---
name: "aio_return"
section: "3p"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/aio_return/3p"
---

# aio\_return(3p)

retrieve return status of an asynchronous I/O operation

## PROLOG

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.

## NAME

aio\_return — retrieve return status of an asynchronous I/O operation

## SYNOPSIS

```
#include <aio.h>
```

ssize\_t aio\_return(struct aiocb \**aiocbp*);

## DESCRIPTION

The *aio\_return*() function shall return the return status associated with the **aiocb** structure referenced by the *aiocbp* argument. The return status for an asynchronous I/O operation is the value that would be returned by the corresponding *read*(), *write*(), or *fsync*() function call. If the error status for the operation is equal to **\[EINPROGRESS\]**, then the return status for the operation is undefined. The *aio\_return*() function may be called exactly once to retrieve the return status of a given asynchronous operation; thereafter, if the same **aiocb** structure is used in a call to *aio\_return*() or *aio\_error*(), an error may be returned. 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.

## 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.

If the *aio\_return*() function fails, it shall return -1 and set *errno* to indicate the error.

## 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.

*The following sections are informative.*

## EXAMPLES

None.

## APPLICATION USAGE

None.

## RATIONALE

None.

## FUTURE DIRECTIONS

None.

## 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\>***

## 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 .