NAME | SYNOPSIS | DESCRIPTION | NOTES | RETURN VALUE | SEE ALSO | COLOPHON
io_uring_register_eventfd(3) liburing Manualio_uring_register_eventfd(3)
io_uring_register_eventfd - register an eventfd with a ring
#include <liburing.h> int io_uring_register_eventfd(struct io_uring *ring, int fd); int io_uring_register_eventfd_async(struct io_uring *ring, int fd); int io_uring_unregister_eventfd(struct io_uring *ring);
io_uring_register_eventfd(3) registers the eventfd file descriptor fd with the ring identified by ring. Whenever completions are posted to the CQ ring, an eventfd notification is generated with the registered eventfd descriptor. If io_uring_register_eventfd_async(3) is used, only events that completed out-of-line will trigger a notification. It notifications are no longer desired, io_uring_unregister_eventfd(3) may be called to remove the eventfd registration. No eventfd argument is needed, as a ring can only have a single eventfd registered.
While io_uring generally takes care to avoid spurious events, they can occur. Similarly, batched completions of CQEs may only trigger a single eventfd notification even if multiple CQEs are posted. The application should make no assumptions on number of events being available having a direct correlation to eventfd notifications posted. An eventfd notification must thus only be treated as a hint to check the CQ ring for completions.
Returns 0 on success, or or -errno on error.
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 firstname.lastname@example.org. This page was obtained from the project's upstream Git repository ⟨https://github.com/axboe/liburing⟩ on 2022-12-17. (At that time, the date of the most recent commit that was found in the repository was 2022-12-12.) 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 email@example.com liburing-2.2 April 16, 2022 io_uring_register_eventfd(3)
Pages that refer to this page: io_uring_register_eventfd(3), io_uring_register_eventfd_async(3), io_uring_unregister_eventfd(3)