.\" Copyright (c) 2004 Hiten Pandya <hmp@dragonflybsd.org>
.\" Copyright (c) 2000 Jonathan M. Bresler
.\"
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.\" $FreeBSD: src/share/man/man9/KASSERT.9,v 1.1.2.4 2001/07/21 09:16:54 schweikh Exp $
.\" $DragonFly: src/share/man/man9/KASSERT.9,v 1.3 2004/05/10 12:22:36 hmp Exp $
.\"
.Dd May 10, 2004
.Os
.Dt KASSERT 9
.Sh NAME
.Nm KASSERT ,
.Nm KKASSERT
.Nd kernel expression verification macros
.Sh SYNOPSIS
.Cd options INVARIANTS
.Fn KASSERT expression "const char *msg"
.Fn KKASERT expression
.Sh DESCRIPTION
The macros described in this manual page are no-op unless the kernel
is compiled with
.Cd "options INVARIANTS" .
.Pp
The
.Fn KASSERT
macro tests the given
.Ar expression
and if it is false,
the
.Xr panic 9
function is called to display
.Fa msg
and terminate the running system.
.Pp
The
.Fn KKASSERT
macro is similar to
.Fn KASSERT ,
except it does not require a description message but instead
displays
.Fa expression
and terminates the running system.
.Sh EXAMPLES
The kernel function
.Fn vput
must not be called with a NULL pointer.
.Bd -literal -offset indent
void
vput(struct vnode *vp)
{
	struct thread *td = curthread;
	
	KASSERT(vp != NULL, ("vput: null vp"));
	...
}
.Ed
.Sh SEE ALSO
.Xr config 8 ,
.Xr panic 9 ,
.Sh AUTHORS
.An -nosplit
This manual page was written by
.An Jonathan M. Bresler
.Aq jmb@FreeBSD.org
and modified for
.Dx
by
.An Hiten Pandya Aq hmp@dragonflybsd.org .