1.\" Copyright (c) 2003 Hiten M. Pandya 2.\" 3.\" All rights reserved. 4.\" 5.\" This program is free software. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 17.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26.\" 27.Dd August 1, 2015 28.Dt CTASSERT 9 29.Os 30.Sh NAME 31.Nm CTASSERT 32.Nd compile time assertion macro 33.Sh SYNOPSIS 34.In sys/param.h 35.In sys/systm.h 36.Fn CTASSERT expression 37.Sh DESCRIPTION 38The 39.Fn CTASSERT 40macro is deprecated and the C11 standard 41.Fn _Static_assert 42should be used instead. 43The header 44.Fa sys/cdefs.h 45should be included to provide compatibility for pre-C11 compilers. 46.Pp 47The 48.Fn CTASSERT 49macro evaluates 50.Fa expression 51at compile time and causes a compiler error if it is false. 52.Pp 53The 54.Fn CTASSERT 55macro is useful for asserting the size or alignment of important 56data structures and variables during compilation, which would 57otherwise cause the code to fail at run time. 58.Sh EXAMPLES 59Assert that the size of the 60.Vt uuid 61structure is 16 bytes. 62.Pp 63.Dl "CTASSERT(sizeof(struct uuid) == 16);" 64.Sh SEE ALSO 65.Xr KASSERT 9 66.Sh AUTHORS 67This manual page was written by 68.An Hiten M. Pandya Aq Mt hmp@FreeBSD.org . 69