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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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NAME | SYNOPSIS | DESCRIPTION | EXAMPLE | RETURN VALUE | SEE ALSO | COLOPHON |
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io_uring_for_each_cqe(3) liburing Manual io_uring_for_each_cqe(3)
io_uring_for_each_cqe - iterate pending completion events
#include <liburing.h>
io_uring_for_each_cqe(struct io_uring *ring,
unsigned head,
struct io_uring_cqe *cqe) { }
The io_uring_for_each_cqe(3) is a macro helper that iterates
completion events belonging to the ring using head as a temporary
iterator, and points cqe to each pending event when iterating.
This helper provides an efficient way to iterate all pending
events in the ring, and then advancing the CQ ring by calling
io_uring_cq_advance(3) with the number of CQEs consumed when done.
As updating the kernel visible CQ ring state involves an ordered
write, doing it once for a number of events is more efficient than
handling each completion separately and calling
io_uring_cqe_seen(3) for each of them.
void handle_cqes(struct io_uring *ring)
{
struct io_uring_cqe *cqe;
unsigned head;
unsigned i = 0;
io_uring_for_each_cqe(ring, head, cqe) {
/* handle completion */
printf("cqe: %d\n", cqe->res);
i++;
}
io_uring_cq_advance(ring, i);
}
None
io_uring_wait_cqe_timeout(3), io_uring_wait_cqe(3),
io_uring_wait_cqes(3), io_uring_cqe_seen(3),
io_uring_buf_ring_cq_advance(3)
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 2025-08-11. (At that time,
the date of the most recent commit that was found in the
repository was 2025-08-02.) 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-2.4 June 04, 2023 io_uring_for_each_cqe(3)
Pages that refer to this page: io_uring_for_each_cqe(3), io_uring_wait_cqes(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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