NAME

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

SYNOPSIS

       #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.

DESCRIPTION

       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, where a NULL timeout waits until at least min_nr events have been seen.  Note
       that timeout is relative.

RETURN VALUE

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

ERRORS

       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 range.

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

       ENOSYS io_getevents() is not implemented on this architecture.

VERSIONS

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

CONFORMING TO

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

NOTES

       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.

BUGS

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

SEE ALSO

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

COLOPHON

       This page is part of release 3.54 of the Linux man-pages project.  A  description  of  the  project,  and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.