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aio_suspend

Section: C Library Functions (3)
Updated: 2026-02-08
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NAME

aio_suspend - wait for asynchronous I/O operation or timeout

LIBRARY

Real-time library (librt,~-lrt)

SYNOPSIS

#include <aio.h>
int aio_suspend(int n;
                const struct aiocb *const aiocb_list[n], int n,
                const struct timespec *restrict timeout);

DESCRIPTION

The aio_suspend() function suspends the calling thread until one of the following occurs:

[bu]: One or more of the asynchronous I/O requests in the list aiocb_list has completed.
[bu]: A signal is delivered.
[bu]: timeout is not NULL and the specified time interval has passed. (For details of the timespec structure, see nanosleep(2).) The n argument specifies the number of items in aiocb_list. Each item in the list pointed to by aiocb_list must be either NULL (and then is ignored), or a pointer to a control block on which I/O was initiated using aio_read(3), aio_write(3), or lio_listio(3). (See aio(7) for a description of the aiocb structure.) If CLOCK_MONOTONIC is supported, this clock is used to measure the timeout interval (see clock_gettime(2)).

RETURN VALUE

If this function returns after completion of one of the I/O requests specified in aiocb_list, 0 is returned. Otherwise, -1 is returned, and errno is set to indicate the error.

ERRORS

EAGAIN: The call timed out before any of the indicated operations had completed.
EINTR: The call was ended by signal (possibly the completion signal of one of the operations we were waiting for); see signal(7).
ENOSYS: aio_suspend() is not implemented.

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
aio_suspend()	Thread safety	MT-Safe

STANDARDS

POSIX.1-2008.

HISTORY

glibc 2.1. POSIX.1-2001. POSIX doesn't specify the parameters to be restrict; that is specific to glibc.

NOTES

One can achieve polling by using a non-NULL timeout that specifies a zero time interval. If one or more of the asynchronous I/O operations specified in aiocb_list has already completed at the time of the call to aio_suspend(), then the call returns immediately. To determine which I/O operations have completed after a successful return from aio_suspend(), use aio_error(3) to scan the list of aiocb structures pointed to by aiocb_list.

BUGS

The glibc implementation of aio_suspend() is not async-signal-safe, in violation of the requirements of POSIX.1.