Date: Tue, 20 Apr 2021 09:22:14 GMT From: Mateusz Piotrowski <0mp@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 33f8d79d7652 - main - assert.3: Document static_assert and _Static_assert Message-ID: <202104200922.13K9ME2h022601@gitrepo.freebsd.org>
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The branch main has been updated by 0mp (doc, ports committer): URL: https://cgit.FreeBSD.org/src/commit/?id=33f8d79d765230e3189876dec9f0dad2d768de1a commit 33f8d79d765230e3189876dec9f0dad2d768de1a Author: Faraz Vahedi <kfv@kfv.io> AuthorDate: 2021-04-20 08:50:36 +0000 Commit: Mateusz Piotrowski <0mp@FreeBSD.org> CommitDate: 2021-04-20 09:17:44 +0000 assert.3: Document static_assert and _Static_assert Reviewed by: imp, 0mp MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D29833 --- share/man/man3/Makefile | 1 + share/man/man3/assert.3 | 37 +++++++++++++++++++++++++++++++++++-- 2 files changed, 36 insertions(+), 2 deletions(-) diff --git a/share/man/man3/Makefile b/share/man/man3/Makefile index d33c0d63ea0d..ea82f04c7825 100644 --- a/share/man/man3/Makefile +++ b/share/man/man3/Makefile @@ -72,6 +72,7 @@ MLINKS= arb.3 ARB8_ENTRY.3 \ arb.3 ARB_RIGHT.3 \ arb.3 ARB_RIGHTIDX.3 \ arb.3 ARB_ROOT.3 +MLINKS+= assert.3 static_assert.3 MLINKS+= ATOMIC_VAR_INIT.3 atomic_compare_exchange_strong.3 \ ATOMIC_VAR_INIT.3 atomic_compare_exchange_strong_explicit.3 \ ATOMIC_VAR_INIT.3 atomic_compare_exchange_weak.3 \ diff --git a/share/man/man3/assert.3 b/share/man/man3/assert.3 index 8bdf076233c8..cc23f96360f0 100644 --- a/share/man/man3/assert.3 +++ b/share/man/man3/assert.3 @@ -28,15 +28,18 @@ .\" @(#)assert.3 8.1 (Berkeley) 6/9/93 .\" $FreeBSD$ .\" -.Dd May 31, 2018 +.Dd April 20, 2021 .Dt ASSERT 3 .Os .Sh NAME -.Nm assert +.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 @@ -81,6 +84,21 @@ The 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);" @@ -95,14 +113,29 @@ 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 +.Rs The .Fn assert macro conforms to .St -isoC-99 . +.Re +.Pp +.Rs +The +.Fn static_assert +macro conforms to +.St -isoC-2011 . +.Re .Sh HISTORY An .Nm
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