KASSERT(9) BSD Kernel Developer's Manual KASSERT(9)NAME
KASSERT -- kernel expression verification macro
SYNOPSIS
options INVARIANTS
#include <sys/param.h>
#include <sys/systm.h>
KASSERT(expression, msg);
DESCRIPTION
In a kernel compiled with options INVARIANTS, the KASSERT() macro tests the given expression and if it is false, calls the panic(9) function,
terminating the running system.
In a kernel that does not have options INVARIANTS, the KASSERT() macro is defined to be a no-op. The second argument is a printf(9) format
string and its arguments, enclosed in parentheses.
EXAMPLES
The kernel function vput() must not be called with a NULL pointer.
void
vput(vp)
struct vnode *vp;
{
struct proc *p = curproc;
KASSERT(vp != NULL, ("vput: null vp"));
...
}
SEE ALSO config(8), panic(9)AUTHORS
This manual page was written by Jonathan M. Bresler <jmb@FreeBSD.org>.
BSD January 14, 2000 BSD
Check Out this Related Man Page
KASSERT(9) BSD Kernel Developer's Manual KASSERT(9)NAME
KASSERT, KASSERTMSG, KDASSERT, KDASSERTMSG -- kernel expression verification macros
SYNOPSIS
void
KASSERT(expression);
void
KASSERTMSG(expression, format, ...);
void
KDASSERT(expression);
void
KDASSERTMSG(expression, format, ...);
DESCRIPTION
These machine independent assertion-checking macros cause a kernel panic(9) if the given expression evaluates to false. Two compile-time
options(4) define the behavior of the checks.
1. The KASSERT() and KASSERTMSG() tests are included only in kernels compiled with the DIAGNOSTIC configuration option. In a kernel that
does not have this configuration option, the macros are defined to be no-ops.
2. The KDASSERT() and KDASSERTMSG() tests are included only in kernels compiled with the DEBUG configuration option. The KDASSERT() and
KASSERT() macros are identical except for the controlling option (DEBUG vs DIAGNOSTIC). Basically, KASSERT() should be used for
light-weight checks and KDASSERT() should be used for heavier ones.
Callers should not rely on the side effects of expression because, depending on the kernel compile options mentioned above, expression might
not be evaluated at all.
The panic message will display the style of assertion (debugging vs. diagnostic), the expression that failed and the filename, and line num-
ber the failure happened on. The KASSERTMSG() and KDASSERTMSG() macros append to the panic(9) format string the message specified by format
and its subsequent arguments, similar to printf(9) functions.
SEE ALSO config(1), options(4), CTASSERT(9), panic(9), printf(9)AUTHORS
These macros were written by Chris G. Demetriou <cgd@netbsd.org>.
BSD September 27, 2011 BSD
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