.\" Copyright (C) 2021 Stefan Roesch <shr@fb.com>
.\"
.\" SPDX-License-Identifier: LGPL-2.0-or-later
.\"
.TH io_uring_register_files 3 "November 15, 2021" "liburing-2.1" "liburing Manual"
.SH NAME
io_uring_register_files \- register file descriptors
.SH SYNOPSIS
.nf
.B #include <liburing.h>
.PP
.BI "int io_uring_register_files(struct io_uring *" ring ","
.BI "                            const int *" files ","
.BI "                            unsigned " nr_files ");"
.PP
.BI "int io_uring_register_files_sparse(struct io_uring *" ring ","
.BI "                            unsigned " nr_files ");"
.fi
.SH DESCRIPTION
.PP
The
.BR io_uring_register_files (3)
function registers
.I nr_files
number of file descriptors defined by the array
.I files
belonging to the
.I ring
for subsequent operations.

The
.BR io_uring_register_files_sparse (3)
function registers an empty file table of
.I nr_files
number of file descriptors. The sparse variant is available in kernels 5.19
and later.

Registering a file table is a prerequisite for using any request that uses
direct descriptors.

.SH RETURN VALUE
On success
.BR io_uring_register_files (3)
and
.BR io_uring_register_files_sparse (3)
return 0. On failure they return
.BR -errno .
.SH SEE ALSO
.BR io_uring_get_sqe (3),
.BR io_uring_unregister_files (3)