1io_uring_prep_poll_add(3) liburing Manual io_uring_prep_poll_add(3)
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6 io_uring_prep_poll_add - prepare a poll request
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9 #include <poll.h>
10 #include <liburing.h>
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12 void io_uring_prep_poll_add(struct io_uring_sqe *sqe,
13 int fd,
14 unsigned poll_mask);
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16 void io_uring_prep_poll_multishot(struct io_uring_sqe *sqe,
17 int fd,
18 unsigned poll_mask);
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21 The io_uring_prep_poll_add(3) function prepares a poll request. The
22 submission queue entry sqe is setup to use the file descriptor fd that
23 should get polled, with the events desired specified in the poll_mask
24 argument.
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26 The default behavior is a single-shot poll request. When the specified
27 event has triggered, a completion CQE is posted and no more events will
28 be generated by the poll request. io_uring_prep_multishot(3) behaves
29 identically in terms of events, but it persist across notifications and
30 will repeatedly post notifications for the same registration. A CQE
31 posted from a multishot poll request will have IORING_CQE_F_MORE set in
32 the CQE flags member, indicating that the application should expect
33 more completions from this request. If the multishot poll request gets
34 terminated or experiences an error, this flag will not be set in the
35 CQE. If this happens, the application should not expect further CQEs
36 from the original request and must reissue a new one if it still wishes
37 to get notifications on this file descriptor.
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41 None
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44 The CQE res field will contain the result of the operation, which is a
45 bitmask of the events notified. See the poll(2) man page for details.
46 Note that where synchronous system calls will return -1 on failure and
47 set errno to the actual error value, io_uring never uses errno. In‐
48 stead it returns the negated errno directly in the CQE res field.
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51 io_uring_get_sqe(3), io_uring_submit(3), poll(2), epoll_ctl(3)
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55liburing-2.2 March 12, 2022 io_uring_prep_poll_add(3)