NAME

       io_uring_prep_timeout_update - prepare a request to update an existing timeout

SYNOPSIS

       #include <liburing.h>

       void io_uring_prep_timeout_update(struct io_uring_sqe *sqe,
                                         struct __kernel_timespec *ts,
                                         __u64 user_data,
                                         unsigned flags);

       void io_uring_prep_timeout_remove(struct io_uring_sqe *sqe,
                                         __u64 user_data,
                                         unsigned flags);

DESCRIPTION

       These  functions modify or cancel an existing timeout request. The submission queue entry sqe is setup to
       arm a timeout update or  removal  specified  by  user_data  and  with  modifier  flags  given  by  flags.
       Additionally, the update request includes a ts structure, which contains new timeout information.

       For an update request, the flags member may contain a bitmask of the following values:

       IORING_TIMEOUT_ABS
              The value specified in ts is an absolute value rather than a relative one.

       IORING_TIMEOUT_BOOTTIME
              The boottime clock source should be used.

       IORING_TIMEOUT_REALTIME
              The realtime clock source should be used.

       IORING_TIMEOUT_ETIME_SUCCESS
              Consider  an expired timeout a success in terms of the posted completion.  Normally a timeout that
              triggers would return in a -ETIME CQE res value.

       The timeout remove command does not currently accept any flags.

RETURN VALUE

       None

ERRORS

       These are the errors that are reported in the CQE res field. On success, 0 is returned.

       -ENOENT
              The timeout identified by user_data could not be found. It may be invalid, or triggered before the
              update or removal request was processed.

       -EALREADY
              The timeout identified by user_data is already firing and cannot be canceled.

       -EINVAL
              One of the fields set in the SQE was invalid. For example, two clocksources  were  given,  or  the
              specified timeout seconds or nanoseconds were < 0.

       -EFAULT
              io_uring was unable to access the data specified by ts.

NOTES

       As  with  any  request that passes in data in a struct, that data must remain valid until the request has
       been successfully submitted. It need  not  remain  valid  until  completion.  Once  a  request  has  been
       submitted,  the  in-kernel  state  is  stable.  Very early kernels (5.4 and earlier) required state to be
       stable until the completion  occurred.  Applications  can  test  for  this  behavior  by  inspecting  the
       IORING_FEAT_SUBMIT_STABLE flag passed back from io_uring_queue_init_params(3).

SEE ALSO

       io_uring_get_sqe(3), io_uring_submit(3), io_uring_prep_timeout(3)

liburing-2.2                                     March 12, 2022                  io_uring_prep_timeout_update(3)