Date: Wed, 15 Mar 2017 21:44:03 -0700 From: "Ngie Cooper (yaneurabeya)" <yaneurabeya@gmail.com> To: Warner Losh <imp@bsdimp.com> Cc: Ngie Cooper <ngie@freebsd.org>, src-committers <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Subject: Re: svn commit: r315360 - head/lib/libkvm Message-ID: <58A53702-FFF6-45E7-ACCD-9B776530064E@gmail.com> In-Reply-To: <CANCZdfqgU8DJTdp4HkVxTU0PNpSGn45wJ0S1su=y2Td_uiVncA@mail.gmail.com> References: <201703160231.v2G2VgxK082641@repo.freebsd.org> <CANCZdfqgU8DJTdp4HkVxTU0PNpSGn45wJ0S1su=y2Td_uiVncA@mail.gmail.com>
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--Apple-Mail=_4FE0695C-43BB-4832-800C-D8D5F039D0B5 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii > On Mar 15, 2017, at 21:32, Warner Losh <imp@bsdimp.com> wrote: >=20 > On Wed, Mar 15, 2017 at 8:31 PM, Ngie Cooper <ngie@freebsd.org> wrote: >> Author: ngie >> Date: Thu Mar 16 02:31:42 2017 >> New Revision: 315360 >> URL: https://svnweb.freebsd.org/changeset/base/315360 >>=20 >> Log: >> Return NULL instead of 0 on failure in _kvm_open, kvm_open{,2,files} >>=20 >> This is being done for the following reasons: >> - kvm_open(3), etc says they will return NULL. >> - NULL by definition is (void*)0 per POSIX, but can be redefined, >> depending on the compiler, etc. >=20 > No, it can't. The C language requires all integral expressions that > evaluate to zero to convert to the NULL pointer. This is independent > of the internal representation of the NULL pointer. >=20 > So this change is an NOP for all compilers. It's a good STYLE change. Someone made an argument a few weeks ago about NULL being definable as a = non-zero value on some esoteric architectures or OSes. I agree though, this is largely stylistic/pedantic for a good cause. If = someone set NULL to something non-zero in value, they would be looking = for pain :). -Ngie --Apple-Mail=_4FE0695C-43BB-4832-800C-D8D5F039D0B5 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJYyhgUAAoJEPWDqSZpMIYVu3IQAKcnuoyftDZrW4T3DVCcT36D 4vprKNb/fVJ0OH9PororOFmw9F/FEHxC4z5FF+sxMsaL9zgSrS30nO7zWpajtSid zb3tcYVGrWm5W5eXPXx0fmpNMrOOPHSSgBrQFAb9t6XNfJC8RlKITNDhMpypX6WC DOywWzW1G/LqtmMemPufw4UmQO7sjYS+gTUPzBkffGvhhjS+HNqIcpgyklBpP/li rHM+HB1flh+mpW6PUO8tdHoI1GxPvKdTpOdDFV6N4nmx4MX1AIz4hlbonG6aAjiR I6D1uzD7oEXGcvSmDriv5c4z3Dc92fZRLKnbDHOGy6P0Cqo5LozWFw2682vJX/vh H2ByhDkZGUwU5IDFnGk1/gr80t+3E0iFmjUSeK4BSkQ6KNRn80WBovLPbdG5fnrJ R44R3fYDbdYdb4FzgJu+qxsNZG7wmpDrpdFUhwBRqJLSywTW6QCySWpPvJd77YV3 KwFLDkkW+b6zaVwBML7KT5ZMIibFM89OB9mJbG/o3whUCOBqbUa0ZfRvY+oNvQIt x9Qs1rv/0e5G5BFN46Am14r5bO9BFTXRzIqMYZOGOYqsA9noJacQa5tirTpncxxO B1IyZsRgyJR50BbHBOVhmrZ5PyWGKrn+Yp9dqgJ7OyITTAcy7/xLXGpT1whwetDI HTQ+AoYgHU86iqAlQGTY =UfoL -----END PGP SIGNATURE----- --Apple-Mail=_4FE0695C-43BB-4832-800C-D8D5F039D0B5--
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