From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/2575 Path: news.gmane.org!not-for-mail From: Rich Felker Newsgroups: gmane.linux.lib.musl.general Subject: Re: musl as a framework to test applications' compatibility with POSIX (was: NULL) Date: Mon, 14 Jan 2013 09:03:34 -0500 Message-ID: <20130114140334.GA29049@brightrain.aerifal.cx> References: <20130113174731.GS4468@port70.net> <1358106388.32505.17@driftwood> <20130114061135.GM20323@brightrain.aerifal.cx> <20130114084527.GA4055@cachalot> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1358172231 6062 80.91.229.3 (14 Jan 2013 14:03:51 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 14 Jan 2013 14:03:51 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-2576-gllmg-musl=m.gmane.org@lists.openwall.com Mon Jan 14 15:04:09 2013 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1Tukdv-00016M-3b for gllmg-musl@plane.gmane.org; Mon, 14 Jan 2013 15:04:03 +0100 Original-Received: (qmail 1552 invoked by uid 550); 14 Jan 2013 14:03:46 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 1539 invoked from network); 14 Jan 2013 14:03:46 -0000 Content-Disposition: inline In-Reply-To: <20130114084527.GA4055@cachalot> User-Agent: Mutt/1.5.21 (2010-09-15) Xref: news.gmane.org gmane.linux.lib.musl.general:2575 Archived-At: On Mon, Jan 14, 2013 at 12:45:27PM +0400, Vasily Kulikov wrote: > Hi, > > On Mon, Jan 14, 2013 at 01:11 -0500, Rich Felker wrote: > > In any case, this thread has gotten WAY off-topic, going all over the > > place into territory about the merits and demerits of different > > languages and anti-FSF politics. Those topics may be worth discussing > > in some contexts, but it seems to have left everybody really confused > > about the issues at hand, which are: > > > > - whether we should work around broken programs that pass NULL to > > variadic functions > > > > - and if so, how > > > > The emerging consensus seems to be using > > > > #define NULL 0L > > > > unconditionally in both C and C++ mode. > > If such slick and unobvious places of C/POSIX/C++/gcc/etc. applications > are explicitly detected and handled, then probably it worth implementing > some checker in libc/toolchain which is detected (probably at runtime) > and warning is emitted at runtime/compile-time? gcc'isms, UBs, etc. > > In musl libc it can be implemented as -DI_WANT_TO_DETECT_GCCISMS. At the very least, this would have to be a macro in the reserved namespace. However, I'm skeptical of using musl as a tool for checking this, especially since the check only works on 64-bit systems and does not help the compiler produce a warning/error, but only causes random, hard-to-diagnose crashes. It looks like cppcheck is adding (or has already added?) a test for incorrectly passing NULL to variadic functions, which is probably where the check belongs. Rich