NAME

       io_uring_submit_and_wait_reg - Sets up and registers fixed wait regions

SYNOPSIS

       #include <liburing.h>

       int io_uring_submit_and_wait_reg(struct io_uring *ring,
                                        struct io_uring_cqe **cqe_ptr,
                                        unsigned wait_nr,
                                        int reg_index);

DESCRIPTION

       The  io_uring_submit_and_wait_reg(3)  submits previously prepared requests in the ring ring and waits for
       wait_nr completions using the registered wait index of reg_index.  Upon successful return, the completion
       events are stored in the cqe_ptr array.

       This function works like io_uring_submit_and_wait_min_timeout(3) in that it supports all the features  of
       that  helper, but rather than pass in all the information in a struct that needs copying, it references a
       registered wait index for which previously registered wait region holds information about  how  the  wait
       should  be  performed.  That  includes information such as the overall timeout, the minimum timeout to be
       used, and so forth. See io_uring_setup_reg_wait(3) for the details on registered wait regions.

       Using registered wait regions has less overhead then other wait methods, as no copying of data is needed.

       It's valid to use this function purely for  waiting  on  events,  even  if  no  new  requests  should  be
       submitted.

RETURN VALUE

       On  success  io_uring_submit_and_wait_reg(3)  returns the number of new requests submitted. On failure it
       returns -errno.  If the kernel doesn't support this functionality, -EINVAL will be returned. If no events
       are submitted and the wait operation times out, then -ETIME will be returned.

SEE ALSO

       io_uring_setup_reg_wait(3), io_uring_submit_and_wait_min_timeout(3), io_uring_submit_and_wait_timeout(3)

liburing-2.9                                    November 2, 2024                 io_uring_submit_and_wait_reg(3)