1.\" $NetBSD: CTASSERT.9,v 1.2 2010/04/05 19:18:45 joerg Exp $ 2.\" Copyright (c) 2003 Hiten M. Pandya 3.\" 4.\" All rights reserved. 5.\" 6.\" This program is free software. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 18.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 21.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27.\" 28.\" $FreeBSD: src/share/man/man9/CTASSERT.9,v 1.3 2008/09/05 15:24:54 emaste Exp $ 29.\" 30.Dd January 24, 2010 31.Dt CTASSERT 9 32.Os 33.Sh NAME 34.Nm CTASSERT 35.Nd compile time assertion macro 36.Sh SYNOPSIS 37.Ft void 38.Fn CTASSERT expression 39.Sh DESCRIPTION 40The 41.Fn CTASSERT 42macro evaluates 43.Fa expression 44at compile time and causes a compiler error if it is false. 45.Pp 46The 47.Fn CTASSERT 48macro is useful for asserting the size or alignment of important 49data structures and variables during compilation, which would 50otherwise cause the code to fail at run time. 51.Sh IMPLEMENTATION NOTES 52The 53.Fn CTASSERT 54macro should not be used in a header file. 55It is implemented using a dummy typedef, with a name (based on line number) 56that may conflict with a 57.Fn CTASSERT 58in a source file including that header. 59.Sh EXAMPLES 60Assert that the size of the 61.Vt uuid 62structure is 16 bytes. 63.Pp 64.Dl "CTASSERT(sizeof(struct uuid) == 16);" 65.Sh SEE ALSO 66.Xr KASSERT 9 67.Sh AUTHORS 68This manual page was written by 69.An Hiten M. Pandya 70.Aq hmp@FreeBSD.org . 71