io_uring_submit_and_wait_timeout(3) liburing Manual io_uring_submit_and_wait_timeout(3)

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:

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)

November 15, 2021 liburing-2.1