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)

liburing-2.3                                    September 6, 2022                       io_uring_prep_send_zc(3)