NAME

       io_uring_prep_send_zc - prepare a zerocopy send request

SYNOPSIS

       #include <liburing.h>

       void io_uring_prep_send_zc(struct io_uring_sqe *sqe,
                                  int sockfd,
                                  const void *buf,
                                  size_t len,
                                  int flags,
                                  unsigned zc_flags);

       void io_uring_prep_send_zc_fixed(struct io_uring_sqe *sqe,
                                        int sockfd,
                                        const void *buf,
                                        size_t len,
                                        int flags,
                                        unsigned zc_flags);
                                        unsigned buf_index);

DESCRIPTION

       The  io_uring_prep_send_zc(3)  function  prepares  a zerocopy send request. The submission
       queue entry sqe is setup to use the file descriptor sockfd to start sending the data  from
       buf of size len bytes with send modifier flags flags and zerocopy modifier flags zc_flags.

       The  io_uring_prep_send_zc_fixed(3)  works  just  like  io_uring_prep_send_zc(3) except it
       requires the use of buffers that have been registered  with  io_uring_register_buffers(3).
       The  buf  and  len  arguments  must  fall  within  a  region specified by buf_index in the
       previously registered buffer. The buffer need  not  be  aligned  with  the  start  of  the
       registered buffer.

       Note  that  using IOSQE_IO_LINK with this request type requires the setting of MSG_WAITALL
       in the flags argument, as a short send isn't considered an error  condition  without  that
       being set.

       These  functions prepare an async zerocopy send(2) request. See that man page for details.
       For details on the zerocopy nature of it, see io_uring_enter(2).

RETURN VALUE

       None

ERRORS

       The CQE res field will contain the result of the operation. See the related man  page  for
       details  on  possible  values.  Note that where synchronous system calls will return -1 on
       failure and set errno to the actual error value, io_uring never uses  errno.   Instead  it
       returns the negated errno directly in the CQE res field.

SEE ALSO

       io_uring_get_sqe(3), io_uring_submit(3), io_uring_prep_send(3), io_uring_enter(2), send(2)