From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 3001 invoked by alias); 4 Feb 2014 17:46:36 -0000 Mailing-List: contact glibc-bugs-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: glibc-bugs-owner@sourceware.org Received: (qmail 2952 invoked by uid 48); 4 Feb 2014 17:46:32 -0000 From: "carlos at redhat dot com" To: glibc-bugs@sourceware.org Subject: [Bug network/16421] IN6_IS_ADDR_UNSPECIFIED can use undefined s6_addr32 Date: Tue, 04 Feb 2014 17:46:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: glibc X-Bugzilla-Component: network X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: carlos at redhat dot com X-Bugzilla-Status: NEW X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: unassigned at sourceware dot org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-02/txt/msg00044.txt.bz2 https://sourceware.org/bugzilla/show_bug.cgi?id=16421 --- Comment #13 from Carlos O'Donell --- (In reply to Octavio Alvarez from comment #12) > Thank you. Today I have learned about statement expressions and how they are > GCC extensions. > > If we add an #ifdef __GNUC__ we would also have to add an #else that avoids > the usage of non-ISO C extensions anyway so Clang do not throw any warnings > or compilers that don't define __GNUC__ still have IN6_* macros available. > Again, two implementations. Now I understand why was the original code in > that form. That's correct. > If the goal is to have a universal implementation it's no use to have it > wrapped in #ifdef __GNUC__. It just stops being universal. Agreed, but have a __GNUC__ version optimized for GNUC is good. > Given the above, there is no use on exposing __in6_u.__u6_addr32 for the > purpose of fixing this bug, then. I don't follow. > Either we go back to patch #1, which keeps both implementations and just > adds the test for definition of __USE_GNU and __USE_MISC macros and does not > break strict compilers, or we remove the #ifdef __GNUC__ implementation > altogether and leave only the #else implementation unconditionally. Not an option. Please leave the __GNUC__ implementation for optimally supporting those using GNU extensions. > Sample of the #else implementation: > # define IN6_IS_ADDR_UNSPECIFIED(a) \ > (((const uint32_t *) (a))[0] == 0 > \ > && ((const uint32_t *) (a))[1] == 0 > \ > && ((const uint32_t *) (a))[2] == 0 > \ > && ((const uint32_t *) (a))[3] == 0) > > I will gladly attach a patch with just the #else implementation for your > review, but I still think the best bet to use the original patch. > > Git commit aff2453d [1] (Dec 2011) shows that originally, only the #else > implementation existed but Ulrich Drepper added a GCC-specific > implementation, apparently to avoid warnings. Later, in commit a784e502 [2] > (Jan 2012), he changed the usage of __const to plain const, removing pre-ISO > C implementations. The fix I'll accept is: - Unconditionally define __u6_* in the union. - Fix all the macros. - Test that. -- You are receiving this mail because: You are on the CC list for the bug.