From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39647) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XcncG-0008BR-Pk for qemu-devel@nongnu.org; Fri, 10 Oct 2014 23:45:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XcncB-0003YF-RZ for qemu-devel@nongnu.org; Fri, 10 Oct 2014 23:45:12 -0400 Message-ID: <5438A7BB.3060109@redhat.com> Date: Fri, 10 Oct 2014 21:44:59 -0600 From: Eric Blake MIME-Version: 1.0 References: <1412996048-6384-1-git-send-email-arei.gonglei@huawei.com> <54389FB1.8040207@huawei.com> <5438A223.2040402@huawei.com> <5438A349.9090403@redhat.com> <5438A4E2.4090007@huawei.com> In-Reply-To: <5438A4E2.4090007@huawei.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="RKpAk1L6s1SGpufk4xEt784Ij14vp179x" Subject: Re: [Qemu-devel] [PATCH] oslib-posix: change free to g_free List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gonglei Cc: "kwolf@redhat.com" , "Huangweidong (C)" , Zhanghailiang , "qemu-trivial@nongnu.org" , "qemu-devel@nongnu.org" , "stefanha@redhat.com" , "pbonzini@redhat.com" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --RKpAk1L6s1SGpufk4xEt784Ij14vp179x Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 10/10/2014 09:32 PM, Gonglei wrote: >>> Actually, I had noted that C standard says it is a no-operation. >>> But that doesn't mean that every C-library handles it like that. >> >> EVERY libc that is C89 compliant handles it like that. The last >> platform that failed on free(NULL) was SunOS 4, which is such >> museum-ware it's not funny. There is no need to cater to platforms fr= om >> 25 years ago. >=20 > But why some callers make a check, > but some other callers don't do this check? Because some people haven't learned that free(NULL) is safe yet. You're welcome to simplify code as you touch it. > Can I consider those check is superfluous? Yes. Checking for NULL before calling free() or g_free() is wasted effor= t. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --RKpAk1L6s1SGpufk4xEt784Ij14vp179x Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg iQEcBAEBCAAGBQJUOKe7AAoJEKeha0olJ0NqtIAIAJhW8iKEHtOlXAN9Y2Hzoddj iTRoXoHUcTWc0xcR11mgataCd957UpaAwVdW7+YYrrqFF0eeNFdE3uZMUzme03Qc 5PkJhPgMR9ov5DHmJC4WVVgE0GB05dA0mTe4W6NDlXcQedszf+E4/Du0ifcNZeng pfx28wkIrg59QQw+eKR41zVpFXV/WbcPW4rInFvjdHsqQpVsRNY1VPiDw8Gct74l AiQ/n821HZHwbDqgGQpfs1A7NfRq/yUJ7OpvXCydCWArlpcNGvREgb16zS/O6gJf AqovQVdxKNtClVbOt3nTnwjcYfp9oKk2CkeXCs+hfg72gDzoIXW/qirSjNfmtpE= =TpgY -----END PGP SIGNATURE----- --RKpAk1L6s1SGpufk4xEt784Ij14vp179x--