io_uring_register_reg_wait(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO | COLOPHON

io_uring_re...er_reg_wait(3) liburing Manual io_uring_re...er_reg_wait(3)

NAME         top

       io_uring_register_reg_wait - Registers fixed wait regions

SYNOPSIS         top

       #include <liburing.h>

       int io_uring_register_reg_wait(struct io_uring *ring,
                                      struct io_uring_reg_wait *reg,
                                      int nr);

DESCRIPTION         top

       The io_uring_register_reg_wait(3) registers a fixed wait region
       starting at reg and of nentries entries with the ring indicated by
       ring.

       This function works like io_uring_setup_reg_wait(3), except it
       doesn't allocate any memory on behalf of the application. The
       application must pass in previously allocated memory in reg, which
       must be of the right size to hold nr entries and suitably aligned
       on a page boundary.

       The memory registered should not be freed until the ring for which
       it is registered is closed.

       Once a wait region has been setup, it persists for the life time
       of the ring.  It's currently not possible to unregister or resize
       a wait region.  Additionally, a wait region may currently only use
       a single page of memory.  On a 4k page size system, this means an
       application is limited to 64 wait regions. That should be enough,
       as each wait index may be modified as needed. With at least 64
       indices available, hopefully applications can just use the
       appropriately setup wait region for each specific type of wait,
       with different indices having different wait settings.

       Available since kernel 6.13.

RETURN VALUE         top

       On success io_uring_register_reg_wait(3) returns 0 .  On failure,
       it returns a -errno value.

SEE ALSO         top

       io_uring_submit_and_wait_reg(3), io_uring_setup_reg_wait(3)

COLOPHON         top

       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 [email protected].  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
       [email protected]

liburing-2.9                 November 2, 2024io_uring_re...er_reg_wait(3)

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