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 47The 48.Fn bus_child_present 49function requests that the parent device driver of 50.Fa dev 51check to see if the 52hardware represented by 53.Fa dev 54is still physically accessible at this time. 55While the notion of accessible varies from bus to bus, generally 56hardware that is not accessible cannot be accessed via the 57.Fn bus_space* 58methods that would otherwise be used to access the device. 59.Pp 60This does not ask the question 61.Dq does this device have children? 62which can better be answered by 63.Xr device_get_children 9 . 64.Sh RETURN VALUES 65A zero return value indicates that the device is not present in the 66system. 67A non-zero return value indicates that the device is present in the 68system, or that the state of the device cannot be determined. 69.Sh EXAMPLES 70This is some example code. 71It only calls stop when the 72.Xr dc 4 73device is actually present. 74.Bd -literal -offset indent 75device_t dev; 76dc_softc *sc; 77 78sc = device_get_softc(dev); 79if (bus_child_present(dev)) 80 dc_stop(sc); 81.Ed 82.Sh SEE ALSO 83.Xr device 9 , 84.Xr driver 9 85.Sh AUTHORS 86This manual page was written by 87.An Warner Losh Aq Mt imp@FreeBSD.org . 88