2003-05-16 15:24:07 +00:00
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.\" Copyright (c) 2003 Hiten M. Pandya
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.\"
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.\" All rights reserved.
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.\"
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.\" This program is free software.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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2008-09-05 15:24:54 +00:00
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.Dd September 5, 2008
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2003-05-16 15:24:07 +00:00
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.Dt CTASSERT 9
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2010-04-14 19:08:06 +00:00
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.Os
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2003-05-16 15:24:07 +00:00
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.Sh NAME
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.Nm CTASSERT
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.Nd compile time assertion macro
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/systm.h
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.Fn CTASSERT expression
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.Sh DESCRIPTION
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The
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2003-05-30 21:13:32 +00:00
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.Fn CTASSERT
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macro evaluates
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.Fa expression
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at compile time and causes a compiler error if it is false.
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.Pp
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The
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2003-05-30 21:13:32 +00:00
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.Fn CTASSERT
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macro is useful for asserting the size or alignment of important
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data structures and variables during compilation, which would
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otherwise cause the code to fail at run time.
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2008-09-05 15:24:54 +00:00
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.Sh IMPLEMENTATION NOTES
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The
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.Fn CTASSERT
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macro should not be used in a header file.
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It is implemented using a dummy typedef, with a name (based on line number)
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that may conflict with a
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.Fn CTASSERT
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in a source file including that header.
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2003-05-16 15:24:07 +00:00
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.Sh EXAMPLES
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Assert that the size of the
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.Vt uuid
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structure is 16 bytes.
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2003-05-30 21:13:32 +00:00
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.Pp
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.Dl "CTASSERT(sizeof(struct uuid) == 16);"
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2003-05-16 15:24:07 +00:00
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.Sh SEE ALSO
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.Xr KASSERT 9
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.Sh AUTHORS
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This manual page was written by
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.An Hiten M. Pandya
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2003-05-30 21:13:32 +00:00
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.Aq hmp@FreeBSD.org .
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