Get the next available 128-byte submission queue
entry from the submission queue
# DESCRIPTION
The [io_uring_get_sqe128] function gets the next available 128-byte
submission queue entry from the submission queue belonging to the *ring*
param.
On success [io_uring_get_sqe128] returns a pointer to the
submission queue entry. On failure **NULL** is returned.
If a submission queue entry is returned, it should be filled out via one
of the prep functions such as [io_uring_prep_uring_cmd128] and
submitted via [io_uring_submit].
Note that neither [io_uring_get_sqe128] nor the prep functions set
(or clear) the **user_data** field of the SQE. If the caller expects
[io_uring_cqe_get_data] or [io_uring_cqe_get_data64] to return
valid data when reaping IO completions, either
[io_uring_sqe_set_data] or [io_uring_sqe_set_data64] **MUST**
have been called before submitting the request.
# RETURN VALUE
[io_uring_get_sqe128] returns a pointer to the next submission
queue event on success and NULL on failure. If **NULL** is returned, the
SQ ring either wasn't created with support for 128-byte SQE entries (
**IORING_SETUP_SQE128** or **IORING_SETUP_SQE_MIXED** ) or is currently
full and entries must be submitted for processing before new ones can
get allocated.
# SEE ALSO
[io_uring_get_sqe], [io_uring_submit],
[io_uring_sqe_set_data]