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).

Linux                                              2019-07-23                                    io_getevents(3)