Copyright (C) 2021 Stefan Roesch <shr@fb.com>

SPDX-License-Identifier: LGPL-2.0-or-later

io_uring_submit_and_wait_timeout - submit requests to the submission queue and wait for the completion with timeout

 #include <liburing.h> 

 "int io_uring_submit_and_wait_timeout(struct io_uring *" ring ","  " struct io_uring_cqe **" cqe_ptr ","  " unsigned " wait_nr ","  " struct __kernel_timespec *" ts ","  " sigset_t *" sigmask ");" 

The io_uring_submit_and_wait_timeout (3) function submits the next requests from the submission queue belonging to the ring and waits for wait_nr completion events, or until the timeout ts expires. The completion events are stored in the cqe_ptr array.

The sigmask specifies the set of signals to block. If set, it is equivalent to atomically executing the following calls:

.EX sigset_t origmask; pthread_sigmask(SIG_SETMASK, &sigmask, &origmask); ret = io_uring_submit_and_wait_timeout(ring, cqe, wait_nr, ts, NULL); pthread_sigmask(SIG_SETMASK, &origmask, NULL);

After the caller retrieves a submission queue entry (SQE) with io_uring_get_sqe (3) and prepares the SQE, it can be submitted with io_uring_submit_and_wait_timeout (3) . Ideally used with a ring setup with IORING_SETUP_SINGLE_ISSUER | IORING_SETUP_DEFER_TASKRUN as that will greatly reduce the number of context switches that an application will see waiting on multiple requests.

On success io_uring_submit_and_wait_timeout (3) returns the number of submitted submission queue entries. On failure it returns -errno . Note that in earlier versions of the liburing library, the return value was 0 on success. The most common failure case is not receiving a completion within the specified timeout, -ETIME is returned in this case. io_uring_queue_init_params (3), io_uring_get_sqe (3), io_uring_submit (3), io_uring_submit_and_wait (3), io_uring_wait_cqe (3)