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

NAME

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

SYNOPSIS

       #include          /* Defines needed types */
       #include             /* 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 3.55 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/.

Linux                            2013-04-08                  IO_GETEVENTS(2)