xref: /freebsd/share/man/man9/device_find_child.9 (revision 2008043f386721d58158e37e0d7e50df8095942d)
1.\" -*- nroff -*-
2.\"
3.\" Copyright (c) 1998 Doug Rabson
4.\"
5.\" All rights reserved.
6.\"
7.\" This program is free software.
8.\"
9.\" Redistribution and use in source and binary forms, with or without
10.\" modification, are permitted provided that the following conditions
11.\" are met:
12.\" 1. Redistributions of source code must retain the above copyright
13.\"    notice, this list of conditions and the following disclaimer.
14.\" 2. Redistributions in binary form must reproduce the above copyright
15.\"    notice, this list of conditions and the following disclaimer in the
16.\"    documentation and/or other materials provided with the distribution.
17.\"
18.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
19.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
22.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28.\"
29.Dd February 8, 2005
30.Dt DEVICE_FIND_CHILD 9
31.Os
32.Sh NAME
33.Nm device_find_child
34.Nd search for a child of a device
35.Sh SYNOPSIS
36.In sys/param.h
37.In sys/bus.h
38.Ft device_t
39.Fn device_find_child "device_t dev" "const char *classname" "int unit"
40.Sh DESCRIPTION
41This function looks for a specific child of
42.Dv dev
43with the given
44.Fa classname
45and
46.Fa unit .
47If
48.Fa unit
49is \-1, it returns the first child of
50.Fa dev
51with a matching
52.Fa classname
53(that is, the one with the lowest unit).
54.Sh RETURN VALUES
55If it exists, the child device is returned, otherwise NULL.
56.Sh SEE ALSO
57.Xr device_add_child 9
58.Sh AUTHORS
59This manual page was written by
60.An Doug Rabson .
61