From owner-svn-src-all@freebsd.org Fri Jan 19 08:24:15 2018 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 7E92EECA714; Fri, 19 Jan 2018 08:24:15 +0000 (UTC) (envelope-from peter@rulingia.com) Received: from vps.rulingia.com (vps.rulingia.com [103.243.244.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mail.rulingia.com", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 190FD77E61; Fri, 19 Jan 2018 08:24:13 +0000 (UTC) (envelope-from peter@rulingia.com) Received: from server.rulingia.com (ppp59-167-167-3.static.internode.on.net [59.167.167.3]) by vps.rulingia.com (8.15.2/8.15.2) with ESMTPS id w0J8NvCb057637 (version=TLSv1.2 cipher=DHE-RSA-CHACHA20-POLY1305 bits=256 verify=OK); Fri, 19 Jan 2018 19:24:03 +1100 (AEDT) (envelope-from peter@rulingia.com) X-Bogosity: Ham, spamicity=0.000000 Received: from server.rulingia.com (localhost.rulingia.com [127.0.0.1]) by server.rulingia.com (8.15.2/8.15.2) with ESMTPS id w0J8NoT1032010 (version=TLSv1.2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256 verify=NO); Fri, 19 Jan 2018 19:23:50 +1100 (AEDT) (envelope-from peter@server.rulingia.com) Received: (from peter@localhost) by server.rulingia.com (8.15.2/8.15.2/Submit) id w0J8Noik032009; Fri, 19 Jan 2018 19:23:50 +1100 (AEDT) (envelope-from peter) Date: Fri, 19 Jan 2018 19:23:50 +1100 From: Peter Jeremy To: Conrad Meyer Cc: Benjamin Kaduk , src-committers , svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r328159 - head/sys/modules Message-ID: <20180119082350.GF75633@server.rulingia.com> References: <201801190434.w0J4Y6i7086677@repo.freebsd.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Hf61M2y+wYpnELGG" Content-Disposition: inline In-Reply-To: X-PGP-Key: http://www.rulingia.com/keys/peter.pgp User-Agent: Mutt/1.9.1 (2017-09-22) X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Jan 2018 08:24:15 -0000 --Hf61M2y+wYpnELGG Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2018-Jan-18 21:07:19 -0800, Conrad Meyer wrote: >The spec says the behavior is undefined; not that the compiler has to >produce a warning or error message. The compiler *does* get to >arbitrarily decide what it wants to do when it encounters UB. It is >wholly free to implement this particular UB with the logical result >and no warning/error. IMO, the fact that our compiler produces a warning message when it encounters undefined behaviour is A Good Thing. Relying on implementation-specific behaviour leads to brittle code - a compiler update or reusing the code with a different compiler could completely change the behaviour. --=20 Peter Jeremy --Hf61M2y+wYpnELGG Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE7rKYbDBnHnTmXCJ+FqWXoOSiCzQFAlphqxZfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEVF QjI5ODZDMzA2NzFFNzRFNjVDMjI3RTE2QTU5N0EwRTRBMjBCMzQACgkQFqWXoOSi CzQzWg//SDAqb4toDa12XynO/m251RJEpcHeU6E5p9GhMGWPOpJAuNsxj62i83N2 Q6FQzfgfNPWi1meBPFnbkeQfVuAlr2ROVmPy6I3qTYHJakq54UBGvd9qip9lhutq Ya7aOxX6U3kbOhDYVi1MGNbSf61Cgx4CYRZ8BG3X5Q/eUDvUt/nW+cQ6QRtk9srO ud4khjkY8adD+G1CYI5dMp89UyJ3RG2DDQfnz7Pn+qlBY4Mw64rtowIIyhj4ahT3 2BwmgBEZCtFV5R97GbQRkBatwK84aDAp5qR/1vDxd/DCg79wUB2zcHjCDa5hXtJ4 rMhovvNR0SqBZqWdYNduVsn47MZBzI0mPTWNto0A3nxKhKWKyZwVCTF57sE6whsn t/pCMU3ZBYg/WjuwwFo7CPBMOEwnfzfu387oaHVNCON3JOYFKKM35PoxMUWAsHYa em0JHxEVnDk7RPV0EOa8bSTd+4lNj6E5F+/g8DRgRoopW16MCC4BRjoA0jZf5hWD eNgOn9WRHkVi+cVzdOKMm+QDxEjc43auhUnuoQyZ5c2vfSWhnnshWnc0pKqGGKrk P3c/ZoCLtLSOaIwhepbOiQ5jSkPI0qZ0B0qhCxCzPOL+tB5hv2Gsqwu4tULojjU6 WeFAHluJ31G7/feWVoPzLkpfWIcUQ2+7iLPIK17560WJjdIK8Hc= =tiV8 -----END PGP SIGNATURE----- --Hf61M2y+wYpnELGG--