mirror of https://github.com/mkerrisk/man-pages
115 lines
2.8 KiB
Groff
115 lines
2.8 KiB
Groff
.\" Copyright (C) 2003 Free Software Foundation, Inc.
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.\" This file is distributed according to the GNU General Public License.
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.\" See the file COPYING in the top level source directory for details.
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.\"
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.\" .de Sh \" Subsection
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.\" ..
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.TH IO_GETEVENTS 2 2008-07-04 "Linux" "Linux Programmer's Manual"
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.SH NAME
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io_getevents \- read asynchronous I/O events from the completion queue
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.SH "SYNOPSIS"
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.nf
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.\" .ad l
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.\" .hy 0
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.B #include <linux/time.h>
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.B #include <libaio.h>
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.\" #include <linux/aio.h>
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.sp
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.\" .HP 19
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.BI "int io_getevents(aio_context_t " ctx_id ", long " min_nr ", long " nr ,
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.BI " struct io_event *" events \
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", struct timespec *" timeout );
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.\" .ad
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.\" .hy
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.sp
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Link with \fI\-laio\fP.
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.fi
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.SH "DESCRIPTION"
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.PP
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.BR io_getevents ()
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attempts to read at least \fImin_nr\fP events and
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up to \fInr\fP events from the completion queue of the AIO context
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specified by \fIctx_id\fP.
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\fItimeout\fP specifies the amount of time to wait for events,
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where a NULL timeout waits until at least \fImin_nr\fP events
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have been seen.
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Note that \fItimeout\fP is relative and will be updated if not NULL
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and the operation blocks.
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.SH "RETURN VALUE"
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On success,
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.BR io_getevents ()
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returns the number of events read: 0 if no events are
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available, or less than \fImin_nr\fP if the \fItimeout\fP has elapsed.
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For the failure return, see NOTES.
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.SH "ERRORS"
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.TP
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.B EFAULT
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Either \fIevents\fP or \fItimeout\fP is an invalid pointer.
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.TP
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.B EINVAL
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\fIctx_id\fP is invalid.
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\fImin_nr\fP is out of range or \fInr\fP is
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out of range.
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.TP
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.B EINTR
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Interrupted by a signal handler; see
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.BR signal (7).
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.TP
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.B ENOSYS
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.BR io_getevents ()
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is not implemented on this architecture.
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.SH "VERSIONS"
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.PP
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The asynchronous I/O system calls first appeared in Linux 2.5, August 2002.
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.SH "CONFORMING TO"
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.PP
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.BR io_getevents ()
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is Linux-specific and should not be used in
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programs that are intended to be portable.
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.SH NOTES
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Glibc does not provide a wrapper function for this system call.
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The wrapper provided in
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.I libaio
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for
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.BR io_getevents ()
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does not follow the usual C library conventions for indicating error:
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on error it returns a negated error number
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(the negative of one of the values listed in ERRORS).
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If the system call is invoked via
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.BR syscall (2),
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then the return value follows the usual conventions for
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indicating an error: \-1, with
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.I errno
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set to a (positive) value that indicates the error.
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.SH "SEE ALSO"
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.PP
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.BR io_cancel (2),
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.BR io_destroy (2),
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.BR io_setup (2),
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.BR io_submit (2),
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.BR time (7)
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.\" .SH "NOTES"
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.\"
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.\" .PP
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.\" The asynchronous I/O system calls were written by Benjamin LaHaise.
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.\"
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.\" .SH AUTHOR
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.\" Kent Yoder.
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