Copyright (c) 2006 Igor Sobrado
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.Dd September 27, 2011 .Dt KASSERT 9 .Os .Sh NAME .Nm KASSERT , .Nm KASSERTMSG , .Nm KDASSERT , .Nm KDASSERTMSG .Nd kernel expression verification macros .Sh SYNOPSIS .Ft void .Fn KASSERT expression .Ft void .Fn KASSERTMSG expression format ... .Ft void .Fn KDASSERT expression .Ft void .Fn KDASSERTMSG expression format ... .Sh DESCRIPTION These machine independent assertion-checking macros cause a kernel .Xr panic 9 if the given .Ar expression evaluates to false. Two compile-time .Xr options 4 define the behavior of the checks. l -enum -offset 2n t The .Fn KASSERT and .Fn KASSERTMSG tests are included only in kernels compiled with the .Dv DIAGNOSTIC configuration option. In a kernel that does not have this configuration option, the macros are defined to be no-ops. t The .Fn KDASSERT and .Fn KDASSERTMSG tests are included only in kernels compiled with the .Dv DEBUG configuration option. The .Fn KDASSERT and .Fn KASSERT macros are identical except for the controlling option
f ( Dv DEBUG vs .Dv DIAGNOSTIC ) . Basically, .Fn KASSERT should be used for light-weight checks and .Fn KDASSERT should be used for heavier ones. .El
p Callers should not rely on the side effects of .Ar expression because, depending on the kernel compile options mentioned above, .Ar expression might not be evaluated at all.
p 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 .Fn KASSERTMSG and .Fn KDASSERTMSG macros append to the .Xr panic 9 format string the message specified by .Fa format and its subsequent arguments, similar to .Xr printf 9 functions. .Sh SEE ALSO .Xr config 1 , .Xr options 4 , .Xr CTASSERT 9 , .Xr panic 9 , .Xr printf 9 .Sh AUTHORS These macros were written by .An Chris G. Demetriou .Aq cgd@netbsd.org .