io_getevents(2)

1IO_GETEVENTS(2)            Linux Programmer's Manual           IO_GETEVENTS(2)
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NAME

6       io_getevents - read asynchronous I/O events from the completion queue
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SYNOPSIS

9       #include <linux/aio_abi.h>         /* Defines needed types */
10       #include <linux/time.h>            /* Defines 'struct timespec' */
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12       int io_getevents(aio_context_t ctx_id, long min_nr, long nr,
13                        struct io_event *events, struct timespec *timeout);
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15       Note: There is no glibc wrapper for this system call; see NOTES.
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DESCRIPTION

18       The  io_getevents() system call attempts to read at least min_nr events
19       and up to nr events from the completion queue of the AIO context speci‐
20       fied  by  ctx_id.  The timeout argument specifies the amount of time to
21       wait for events, where a NULL  timeout  waits  until  at  least  min_nr
22       events have been seen.  Note that timeout is relative.
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RETURN VALUE

25       On  success,  io_getevents() returns the number of events read: 0 if no
26       events are available, or less than min_nr if the timeout  has  elapsed.
27       For the failure return, see NOTES.
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ERRORS

30       EFAULT Either events or timeout is an invalid pointer.
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32       EINVAL ctx_id  is  invalid.   min_nr  is  out  of range or nr is out of
33              range.
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35       EINTR  Interrupted by a signal handler; see signal(7).
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37       ENOSYS io_getevents() is not implemented on this architecture.
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VERSIONS

40       The asynchronous I/O system calls first appeared in Linux 2.5.
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CONFORMING TO

43       io_getevents() is Linux-specific and should not  be  used  in  programs
44       that are intended to be portable.
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NOTES

47       Glibc  does  not  provide a wrapper function for this system call.  You
48       could invoke it using syscall(2).  But instead, you  probably  want  to
49       use the io_getevents() wrapper function provided by libaio.
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51       Note  that  the  libaio wrapper function uses a different type (io_con‐
52       text_t) for the ctx_id argument.  Note also  that  the  libaio  wrapper
53       does  not follow the usual C library conventions for indicating errors:
54       on error it returns a negated error number (the negative of one of  the
55       values   listed  in  ERRORS).   If  the  system  call  is  invoked  via
56       syscall(2), then the return value follows  the  usual  conventions  for
57       indicating  an  error:  -1,  with  errno set to a (positive) value that
58       indicates the error.
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BUGS

61       An invalid ctx_id may cause a segmentation fault instead of  genenerat‐
62       ing the error EINVAL.
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COLOPHON

68       This  page  is  part of release 3.53 of the Linux man-pages project.  A
69       description of the project, and information about reporting  bugs,  can
70       be found at http://www.kernel.org/doc/man-pages/.
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74Linux                             2013-04-08                   IO_GETEVENTS(2)