Section (2) io_getevents
Name
io_getevents — read asynchronous I/O events from the completion queue
Synopsis
#include <linux/aio_abi.h> /* Defines needed types */ #include <linux/time.h> /* Defines _zsingle_quotesz_struct timespec_zsingle_quotesz_ */
int
io_getevents( |
aio_context_t ctx_id, |
long min_nr, | |
long nr, | |
struct io_event *events, | |
struct timespec *timeout) ; |
![]() |
Note |
---|---|
There is no glibc wrapper for this system call; see NOTES. |
DESCRIPTION
The io_getevents
() system
call attempts to read at least min_nr
events and up to
nr
events from the
completion queue of the AIO context specified by ctx_id
.
The timeout
argument specifies the amount of time to wait for events, and
is specified as a relative timeout in a structure of the
following form:
struct timespec { time_t tv_sec
; /* seconds */long tv_nsec
; /* nanoseconds [0 .. 999999999] */};
The specified time will be rounded up to the system clock granularity and is guaranteed not to expire early.
Specifying timeout
as NULL means block indefinitely until at least min_nr
events have been
obtained.
RETURN VALUE
On success, io_getevents
()
returns the number of events read. This may be 0, or a value
less than min_nr
, if
the timeout
expired.
It may also be a nonzero value less than min_nr
, if the call was
interrupted by a signal handler.
For the failure return, see NOTES.
ERRORS
- EFAULT
-
Either
events
ortimeout
is an invalid pointer. - EINTR
-
Interrupted by a signal handler; see signal(7).
- EINVAL
-
ctx_id
is invalid.min_nr
is out of range ornr
is out of range. - ENOSYS
-
io_getevents
() is not implemented on this architecture.
CONFORMING TO
io_getevents
() is
Linux-specific and should not be used in programs that are
intended to be portable.
NOTES
Glibc does not provide a wrapper function for this system
call. You could invoke it using syscall(2). But instead,
you probably want to use the io_getevents
() wrapper function provided by
libaio
.
Note that the libaio
wrapper function uses
a different type (io_context_t) for
the ctx_id
argument.
Note also that the libaio
wrapper does not
follow the usual C library conventions for indicating errors:
on error it returns a negated error number (the negative of
one of the values listed in ERRORS). If the system call is
invoked via syscall(2), then the return
value follows the usual conventions for indicating an error:
−1, with errno
set to a
(positive) value that indicates the error.
COLOPHON
This page is part of release 5.04 of the Linux man-pages
project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
Copyright (C) 2003 Free Software Foundation, Inc. %%%LICENSE_START(GPL_NOVERSION_ONELINE) This file is distributed according to the GNU General Public License. %%%LICENSE_END |