io_uring_wait_cqe_nr(3) — Linux manual page

io_uring_wait_cqe_nr(3)      liburing Manual     io_uring_wait_cqe_nr(3)

NAME

       io_uring_wait_cqe_nr - wait for one or more io_uring completion
       events

SYNOPSIS

       #include <liburing.h>

       int io_uring_wait_cqe_nr(struct io_uring *ring,
                                struct io_uring_cqe **cqe_ptr,
                                unsigned wait_nr);

DESCRIPTION

       The io_uring_wait_cqe_nr(3) function returns wait_nr IO
       completion events from the queue belonging to the ring param,
       waiting for it if necessary. If the requested number of events
       are already available in the ring when invoked, no waiting will
       occur. The cqe_ptr param is filled in on success.

       After the caller has submitted a request with io_uring_submit(3),
       the application can retrieve the completion with
       io_uring_wait_cqe(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_wait_cqe_nr(3) returns 0 and the cqe_ptr
       param is filled in. On failure it returns -errno.  The return
       value indicates the result of waiting for a CQE, and it has no
       relation to the CQE result itself.

SEE ALSO

       io_uring_queue_init_params(3), io_uring_submit(3),
       io_uring_wait_cqes(3)

COLOPHON

       This page is part of the liburing (A library for io_uring)
       project.  Information about the project can be found at 
       ⟨https://github.com/axboe/liburing⟩.  If you have a bug report for
       this manual page, send it to io-uring@vger.kernel.org.  This page
       was obtained from the project's upstream Git repository
       ⟨https://github.com/axboe/liburing⟩ on 2024-06-14.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2024-06-03.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

liburing-2.1                November 15, 2021    io_uring_wait_cqe_nr(3)

Pages that refer to this page: io_uring_wait_cqe_nr(3)

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