'\" t
.\" Copyright (c) 2003 Andries Brouwer (aeb@cwi.nl)
.\" and Copyright (C) 2010 Michael Kerrisk <mtk.manpages@gmail.com>
.\"
.\" SPDX-License-Identifier: GPL-2.0-or-later
.\"
.TH aio_suspend 3 (date) "Linux man-pages (unreleased)"
.SH NAME
aio_suspend \- wait for asynchronous I/O operation or timeout
.SH LIBRARY
Real-time library
.RI ( librt ", " \-lrt )
.SH SYNOPSIS
.nf
.P
.B "#include <aio.h>"
.P
.BI "int aio_suspend(const struct aiocb *const " aiocb_list "[], int " nitems ,
.BI " const struct timespec *restrict " timeout );
.fi
.SH DESCRIPTION
The
.BR aio_suspend ()
function suspends the calling thread until one of the following occurs:
.IP \[bu] 3
One or more of the asynchronous I/O requests in the list
.I aiocb_list
has completed.
.IP \[bu]
A signal is delivered.
.IP \[bu]
.I timeout
is not NULL and the specified time interval has passed.
(For details of the
.I timespec
structure, see
.BR nanosleep (2).)
.P
The
.I nitems
argument specifies the number of items in
.IR aiocb_list .
Each item in the list pointed to by
.I aiocb_list
must be either NULL (and then is ignored),
or a pointer to a control block on which I/O was initiated using
.BR aio_read (3),
.BR aio_write (3),
or
.BR lio_listio (3).
(See
.BR aio (7)
for a description of the
.I aiocb
structure.)
.P
If
.B CLOCK_MONOTONIC
is supported, this clock is used to measure
the timeout interval (see
.BR clock_gettime (2)).
.SH RETURN VALUE
If this function returns after completion of one of the I/O
requests specified in
.IR aiocb_list ,
0 is returned.
Otherwise, \-1 is returned, and
.I errno
is set to indicate the error.
.SH ERRORS
.TP
.B EAGAIN
The call timed out before any of the indicated operations
had completed.
.TP
.B EINTR
The call was ended by signal
(possibly the completion signal of one of the operations we were
waiting for); see
.BR signal (7).
.TP
.B ENOSYS
.BR aio_suspend ()
is not implemented.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbx lb lb
l l l.
Interface Attribute Value
T{
.na
.nh
.BR aio_suspend ()
T} Thread safety MT-Safe
.TE
.SH STANDARDS
POSIX.1-2008.
.SH HISTORY
glibc 2.1.
POSIX.1-2001.
.P
POSIX doesn't specify the parameters to be
.IR restrict ;
that is specific to glibc.
.SH NOTES
One can achieve polling by using a non-NULL
.I timeout
that specifies a zero time interval.
.P
If one or more of the asynchronous I/O operations specified in
.I aiocb_list
has already completed at the time of the call to
.BR aio_suspend (),
then the call returns immediately.
.P
To determine which I/O operations have completed
after a successful return from
.BR aio_suspend (),
use
.BR aio_error (3)
to scan the list of
.I aiocb
structures pointed to by
.IR aiocb_list .
.SH BUGS
The glibc implementation of
.BR aio_suspend ()
is not async-signal-safe,
.\" FIXME . https://sourceware.org/bugzilla/show_bug.cgi?id=13172
in violation of the requirements of POSIX.1.
.SH SEE ALSO
.BR aio_cancel (3),
.BR aio_error (3),
.BR aio_fsync (3),
.BR aio_read (3),
.BR aio_return (3),
.BR aio_write (3),
.BR lio_listio (3),
.BR aio (7),
.BR time (7)
