1.\" -*- nroff -*- 2.\" 3.\" Copyright (c) 2000 Jonathan M. Bresler 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 January 14, 2000 32.Dt KASSERT 9 33.Os 34.Sh NAME 35.Nm KASSERT 36.Nd kernel expression verification macro 37.Sh SYNOPSIS 38.Cd "options INVARIANTS" 39.Pp 40.In sys/param.h 41.In sys/systm.h 42.Fn KASSERT expression msg 43.Sh DESCRIPTION 44In a kernel compiled with 45.Cd "options INVARIANTS" , 46the 47.Fn KASSERT 48macro tests the given 49.Fa expression 50and if it is false, 51calls the 52.Xr panic 9 53function, terminating the running system. 54.Pp 55In a kernel that does not have 56.Cd "options INVARIANTS" , 57the 58.Fn KASSERT 59macro is defined to be a no-op. 60The 61second argument is a 62.Xr printf 9 63format string and its arguments, 64enclosed in parentheses. 65.Sh EXAMPLES 66The kernel function 67.Fn vput 68must not be called with a 69.Dv NULL 70pointer. 71.Bd -literal -offset indent 72void 73vput(vp) 74 struct vnode *vp; 75{ 76 struct proc *p = curproc; 77 KASSERT(vp != NULL, ("vput: null vp")); 78 ... 79} 80.Ed 81.Sh SEE ALSO 82.Xr config 8 , 83.Xr panic 9 84.Sh AUTHORS 85This manual page was written by 86.An Jonathan M. Bresler Aq Mt jmb@FreeBSD.org . 87