.\" Copyright (C) 2022 Jens Axboe <axboe@kernel.dk>
.\"
.\" SPDX-License-Identifier: LGPL-2.0-or-later
.\"
.TH io_uring_prep_send_zc 3 "September 6, 2022" "liburing-2.3" "liburing Manual"
.SH NAME
io_uring_prep_send_zc \- prepare a zerocopy send request
.SH SYNOPSIS
.nf
.B #include <liburing.h>
.PP
.BI "void io_uring_prep_send_zc(struct io_uring_sqe *" sqe ","
.BI "                        int " sockfd ","
.BI "                        const void *" buf ","
.BI "                        size_t " len ","
.BI "                        int " flags ","
.BI "                        int " zc_flags ");"
.fi
.SH DESCRIPTION
.PP
The
.BR io_uring_prep_send_zc (3)
function prepares a zerocopy send request. The submission queue entry
.I sqe
is setup to use the file descriptor
.I sockfd
to start sending the data from
.I buf
of size
.I len
bytes with send modifier flags
.IR flags
and zerocopy modifier flags
.IR zc_flags .

This function prepares an async zerocopy
.BR send (2)
request. See that man page for details. For details on the zerocopy nature
of it, see
.BR io_uring_enter (2) .

.SH RETURN VALUE
None
.SH ERRORS
The CQE
.I 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
.B -1
on failure and set
.I errno
to the actual error value, io_uring never uses
.IR errno .
Instead it returns the negated
.I errno
directly in the CQE
.I res
field.
.SH SEE ALSO
.BR io_uring_get_sqe (3),
.BR io_uring_submit (3),
.BR io_uring_prep_send (3),
.BR io_uring_enter (2),
.BR send (2)