KASSERT(9) FreeBSD 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 number
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 <
[email protected]>.
FreeBSD 14.1-RELEASE-p8 September 27, 2011 FreeBSD 14.1-RELEASE-p8