io_uring_prep_poll_add(3) — Linux manual page


io_uring_prep_poll_add(3)    liburing Manual   io_uring_prep_poll_add(3)

NAME         top

       io_uring_prep_poll_add - prepare a poll request

SYNOPSIS         top

       #include <poll.h>
       #include <liburing.h>

       void io_uring_prep_poll_add(struct io_uring_sqe *sqe,
                                   int fd,
                                   unsigned poll_mask);

       void io_uring_prep_poll_multishot(struct io_uring_sqe *sqe,
                                         int fd,
                                         unsigned poll_mask);

DESCRIPTION         top

       The io_uring_prep_poll_add(3) function prepares a poll request.
       The submission queue entry sqe is setup to use the file
       descriptor fd that should get polled, with the events desired
       specified in the poll_mask argument.

       The default behavior is a single-shot poll request. When the
       specified event has triggered, a completion CQE is posted and no
       more events will be generated by the poll request.
       io_uring_prep_poll_multishot(3) behaves identically in terms of
       events, but it persist across notifications and will repeatedly
       post notifications for the same registration. A CQE posted from a
       multishot poll request will have IORING_CQE_F_MORE set in the CQE
       flags member, indicating that the application should expect more
       completions from this request. If the multishot poll request gets
       terminated or experiences an error, this flag will not be set in
       the CQE. If this happens, the application should not expect
       further CQEs from the original request and must reissue a new one
       if it still wishes to get notifications on this file descriptor.

RETURN VALUE         top


ERRORS         top

       The CQE res field will contain the result of the operation, which
       is a bitmask of the events notified. See the poll(2) man page for
       details. Note that where synchronous system calls will return -1
       on failure and set errno to the actual error value, io_uring
       never uses errno.  Instead it returns the negated errno directly
       in the CQE res field.

SEE ALSO         top

       io_uring_get_sqe(3), io_uring_submit(3), poll(2), epoll_ctl(3)

COLOPHON         top

       This page is part of the liburing (A library for io_uring)
       project.  Information about the project can be found at 
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       this manual page, send it to  This page
       was obtained from the project's upstream Git repository
       ⟨⟩ on 2022-12-17.  (At that
       time, the date of the most recent commit that was found in the
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liburing-2.2                 March 12, 2022    io_uring_prep_poll_add(3)

Pages that refer to this page: io_uring_prep_poll_add(3)io_uring_prep_poll_multishot(3)io_uring_prep_poll_update(3)