1.\" -*- nroff -*- 2.\" 3.\" Copyright (c) 2003 M. Warner Losh 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.\" $FreeBSD$ 30.\" 31.Dd March 27, 2003 32.Dt BUS_CHILD_PRESENT 9 33.Os 34.Sh NAME 35.Nm bus_child_present 36.Nd Ask the bus driver to see if this device is still really present. 37.Sh SYNOPSIS 38.In sys/param.h 39.In sys/bus.h 40.Pp 41.In machine/bus.h 42.In sys/rman.h 43.In machine/resource.h 44.Ft int 45.Fn bus_child_present "device_t dev" 46.Sh DESCRIPTION 47Requests that the parent device driver of 48.Fa dev 49check to see if the 50hardware represented by 51.Fa dev 52is still physically accessible at this time. 53While the notion of accessible varies from bus to bus, generally 54hardware that is not acceessible cannot be accessed via the bus_space 55methods that would otherwise be used to acceess the device. 56.Pp 57This does not ask the question 'does this device have children?' which 58can better be answered by 59.Xr device_get_children 9 . 60.Sh RETURN VALUES 61A zero return value indicates that the device is not present in the 62system. 63A non-zero return value indicates that the device is present in the 64system, or that the state of the device cannot be determined. 65.Sh EXAMPLES 66This is some example code. 67It only calls stop when the dc device is actually present. 68.Bd -literal 69 device_t dev; 70 dc_softc *sc; 71 72 sc = device_get_softc(dev); 73 if (bus_child_present(dev)) 74 dc_stop(sc); 75.Ed 76.Sh SEE ALSO 77.Xr device 9 , 78.Xr driver 9 79.Sh AUTHORS 80.An -nosplit 81This man page was written by 82.An Warner Losh Aq imp@FreeBSD.org . 83