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diff --git a/static/freebsd/man3/assert.3 b/static/freebsd/man3/assert.3 new file mode 100644 index 00000000..f219aa1d --- /dev/null +++ b/static/freebsd/man3/assert.3 @@ -0,0 +1,136 @@ +.\" Copyright (c) 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.Dd April 20, 2021 +.Dt ASSERT 3 +.Os +.Sh NAME +.Nm assert , +.Nm static_assert +.Nd expression verification macro +.Sh SYNOPSIS +.In assert.h +.Fn assert expression +.Fn static_assert expression +.Fn static_assert expression message +.Sh DESCRIPTION +The +.Fn assert +macro tests the given +.Ar expression +and if it is false, +the calling process is terminated. +A diagnostic message is written to +.Dv stderr +and the function +.Xr abort 3 +is called, effectively terminating the program. +.Pp +If +.Ar expression +is true, +the +.Fn assert +macro does nothing. +.Pp +The +.Fn assert +macro +may be removed at compile time by defining +.Dv NDEBUG +as a macro +(e.g., by using the +.Xr cc 1 +option +.Fl D Ns Dv NDEBUG ) . +Unlike most other include files, +.In assert.h +may be included multiple times. +Each time whether or not +.Dv NDEBUG +is defined determines the behavior of assert from that point forward +until the end of the unit or another include of +.In assert.h . +.Pp +The +.Fn assert +macro should only be used for ensuring the developer's expectations +hold true. +It is not appropriate for regular run-time error detection. +.Pp +The +.Fn static_assert +macro expands to +.Fn _Static_assert , +and, contrarily to +.Fn assert , +makes assertions at compile-time. +Once the constraint is violated, the compiler produces a diagnostic +message including the string literal message, if provided. +The initial form of the +.Fn _Static_assert +containing a string literal message was introduced in C11 standard, and +the other form with no string literal is to be implemented by C2x and +some compilers may lack its adoption at present. +.Sh EXAMPLES +The assertion: +.Dl "assert(1 == 0);" +generates a diagnostic message similar to the following: +.Dl "Assertion failed: (1 == 0), function main, file main.c, line 100." +.Pp +The following assert tries to assert there was no partial read: +.Dl "assert(read(fd, buf, nbytes) == nbytes);" +However, there are two problems. +First, it checks for normal conditions, rather than conditions that +indicate a bug. +Second, the code will disappear if +.Dv NDEBUG +is defined, changing the semantics of the program. +.Pp +The following asserts that the size of the S structure is 16. +Otherwise, it produces a diagnostic message which points at the +constraint and includes the provided string literal: +.Dl "static_assert(sizeof(struct S) == 16, ""size mismatch"");" +If none is provided, it only points at the constraint. +.Sh SEE ALSO +.Xr abort2 2 , +.Xr abort 3 +.Sh STANDARDS +The +.Fn assert +macro conforms to +.St -isoC-99 . +.Pp +The +.Fn static_assert +macro conforms to +.St -isoC-2011 . +.Sh HISTORY +An +.Nm +macro appeared in +.At v7 . |
