CTASSERT(9) BSD Kernel Developer's Manual CTASSERT(9)NAME
CTASSERT -- compile time assertion macro
SYNOPSIS
#include <sys/param.h>
#include <sys/systm.h>
CTASSERT(expression);
DESCRIPTION
The CTASSERT() macro evaluates expression at compile time and causes a compiler error if it is false.
The CTASSERT() macro is useful for asserting the size or alignment of important data structures and variables during compilation, which would
otherwise cause the code to fail at run time.
IMPLEMENTATION NOTES
The CTASSERT() macro should not be used in a header file. It is implemented using a dummy typedef, with a name (based on line number) that
may conflict with a CTASSERT() in a source file including that header.
EXAMPLES
Assert that the size of the uuid structure is 16 bytes.
CTASSERT(sizeof(struct uuid) == 16);
SEE ALSO KASSERT(9)AUTHORS
This manual page was written by Hiten M. Pandya <hmp@FreeBSD.org>.
BSD September 5, 2008 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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