io_uring_submit_and_wait_timeout3

Usage

#include <liburing.h>

Overview

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.

Return value

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.