1.\" Copyright (c) 1998 Doug Rabson 2.\" 3.\" All rights reserved. 4.\" 5.\" This program is free software. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 17.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26.\" 27.\" $FreeBSD: src/share/man/man9/BUS_READ_IVAR.9,v 1.3.2.4 2001/12/17 11:30:18 ru Exp $ 28.\" $DragonFly: src/share/man/man9/BUS_READ_IVAR.9,v 1.3 2004/06/01 11:36:53 hmp Exp $ 29.\" 30.Dd June 16, 1998 31.Dt BUS_READ_IVAR 9 32.Os 33.Sh NAME 34.Nm BUS_READ_IVAR , 35.Nm BUS_WRITE_IVAR 36.Nd manipulate bus-specific device instance variables 37.Sh SYNOPSIS 38.In sys/param.h 39.In sys/bus.h 40.Ft int 41.Fn BUS_READ_IVAR "device_t dev" "device_t child" "int index" "uintptr_t *result" 42.Ft int 43.Fn BUS_WRITE_IVAR "device_t dev" "device_t child" "int index" "uintptr_t value" 44.Sh DESCRIPTION 45These two methods manage a bus specific set of instance variables of 46a child device. The intention is that each different type of bus 47defines a set of appropriate instance variables (such as ports and 48irqs for ISA bus etc.) 49.Pp 50This information could be given to the child device as a struct but 51that makes it hard for a bus to add or remove variables without 52forcing an edit and recompile for all drivers which may not be 53possible for vendor supplied binary drivers. 54.Sh RETURN VALUES 55Zero is returned on success, otherwise an appropriate error is returned. 56.Sh SEE ALSO 57.Xr device 9 , 58.Xr driver 9 59.Sh AUTHORS 60This man page was written by 61.An Doug Rabson . 62