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


       #include <linux/aio_abi.h>         /* Defines needed types */
       #include <linux/time.h>            /* Defines 'struct timespec' */

       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.


       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

           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.


       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.


       EFAULT Either events or timeout is an invalid pointer.

       EINVAL ctx_id is invalid.  min_nr is out of  range  or  nr  is  out  of

       EINTR  Interrupted by a signal handler; see signal(7).

       ENOSYS io_getevents() is not implemented on this architecture.


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


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


       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.


       An  invalid ctx_id may cause a segmentation fault instead of generating
       the error EINVAL.


       io_cancel(2), io_destroy(2), io_setup(2), io_submit(2), aio(7), time(7)


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