aio_return()

Updated: April 19, 2023

Get the return status for an asynchronous I/O operation

Synopsis:

#include <aio.h>

ssize_t aio_return( struct aiocb * aiocbptr );

Arguments:

aiocbptr
A pointer to an asynchronous I/O control block of type aiocb whose return status you want to get.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The aio_return() function returns the return status associated with the aiocb structure referenced by the aiocbptr argument. The return status for an asynchronous I/O operation is the value that's returned by the corresponding read(), write(), or fsync() operation.

You can call aio_return() exactly once to retrieve the return status of a given asynchronous operation; if you use the same aiocb structure for the same operation in a call to aio_return() or aio_error(), an error may be returned.

Returns:

The value that's returned by the corresponding read(), write(), or fsync() operation.

Errors:

EINVAL
The aiocbptr argument doesn't refer to an asynchronous operation whose return status hasn't yet been retrieved.

Classification:

POSIX 1003.1

Safety:  
Cancellation point No
Interrupt handler No
Signal handler Yes
Thread Yes

Caveats:

The first time you call an aio_* function, a thread pool is created, making your process multithreaded if it isn't already. Because of this, after a fork() the child can not use any of the aio_*() functions if the parent used any aio_*() functions before the fork(). The thread pool isn't destroyed until your process ends.