NAME

       io_getevents, aio_pgetevents - Read resulting events from io requests

SYNOPSIS

       #include <errno.h>

       #include <libaio.h>

       struct iocb {
            void      *data;
            unsigned  key;
            short          aio_lio_opcode;
            short          aio_reqprio;
            int       aio_fildes;
       };

       struct io_event {
               unsigned        PADDED(data, __pad1);
               unsigned        PADDED(obj,  __pad2);
               unsigned        PADDED(res,  __pad3);
               unsigned        PADDED(res2, __pad4);
       };

       int io_getevents(io_context_t ctx, long nr, struct io_event *events[], struct timespec *timeout);
       int io_pgetevents(io_context_t ctx, long nr, struct io_event *events[], struct timespec *timeout, sigset_t *sigmask);

DESCRIPTION

       Attempts  to  read up to nr events from the completion queue for the aio_context specified
       by ctx.

RETURN VALUES

       May return 0 if no events are available and the timeout specified  by  when  has  elapsed,
       where  when  ==  NULL  specifies an infinite timeout.  Note that the timeout pointed to by
       when is relative and will be updated if not NULL and the operation blocks.  Will fail with
       ENOSYS if not implemented.

   io_pgetevents()
       The   relationship   between  io_getevents()  and  io_pgetevents()  is  analogous  to  the
       relationship between select(2) and pselect(2): similar to pselect(2), pgetevents()  allows
       an  application  to  safely  wait  until either an aio completion event happens or until a
       signal is caught.

       The following io_pgetevents() call:

           ret = io_pgetevents(ctx, min_nr, nr, events, timeout, sigmask);

       is equivalent to atomically executing the following calls:

           sigset_t origmask;

           pthread_sigmask(SIG_SETMASK, &sigmask, &origmask);
           ret = io_getevents(ctx, min_nr, nr, events, timeout);
           pthread_sigmask(SIG_SETMASK, &origmask, NULL);

       See the description of pselect(2) for an explanation of why io_pgetevents() is necessary.

       If the sigmask argument is  specified  as  NULL,  then  no  signal  mask  manipulation  is
       performed (and thus io_pgetevents() behaves the same as io_getevents()).

ERRORS

       EINVAL If ctx is invalid, if min_nr is out of range, if nr is out of range, if when is out
              of range.

       EFAULT If any of the memory specified to is invalid.

SEE ALSO

       io(3), io_cancel(3), io_fsync(3), io_prep_fsync(3),  io_prep_pread(3),  io_prep_pwrite(3),
       io_queue_init(3),       io_queue_release(3),       io_queue_run(3),      io_queue_wait(3),
       io_set_callback(3), io_submit(3), errno(3), pselect(2).