io_uring_register_zcrx_ctrl(3)  liburing Manual io_uring_register_zcrx_ctrl(3)

NAME
       io_uring_register_zcrx_ctrl - perform control operations on a zero-copy
       receive context

SYNOPSIS
       #include <liburing.h>

       int io_uring_register_zcrx_ctrl(struct io_uring *ring,
                                       struct zcrx_ctrl *ctrl);

DESCRIPTION
       The io_uring_register_zcrx_ctrl(3) function performs control operations
       on a previously registered zero-copy receive context. See
       io_uring_register_ifq(3) for details on registering a zero-copy receive
       context.

       The ctrl argument must point to a struct zcrx_ctrl structure that
       describes the control operation to perform:


           struct zcrx_ctrl {
               __u32 zcrx_id;
               __u32 op;
               __u64 __resv[2];
               union {
                   struct zcrx_ctrl_export     zc_export;
                   struct zcrx_ctrl_flush_rq   zc_flush;
               };
           };

       The zcrx_id field must be set to the ID of the zero-copy receive
       context returned from io_uring_register_ifq(3).  The op field specifies
       the control operation to perform and can be one of:


       ZCRX_CTRL_FLUSH_RQ
              Flushes pending buffers from the refill queue. Uses the zc_flush
              member of the union.


       ZCRX_CTRL_EXPORT
              Exports the zero-copy receive context for use by other rings.
              Uses the zc_export member of the union. Upon successful export,
              the zcrx_fd field in zc_export will contain the file descriptor
              that can be used to share this context with other io_uring
              instances.


       The reserved __resv fields must be cleared to zero.


RETURN VALUE
       Returns 0 on success. On error, a negative errno value is returned.


NOTES
       This function is available since Linux kernel 6.15.


SEE ALSO
       io_uring_register(2), io_uring_register_ifq(3)

liburing-2.15                   March 26, 2026  io_uring_register_zcrx_ctrl(3)