Date: Mon, 21 Apr 2003 12:48:40 +0200 From: Erik Trulsson <ertr1013@student.uu.se> To: "M. Warner Losh" <imp@bsdimp.com> Cc: schweikh@freebsd.org Subject: Re: standards/50889: NULL defined as 0 instead of (void *)0 Message-ID: <20030421104840.GA92922@falcon.midgard.homeip.net> In-Reply-To: <20030421.020106.41513803.imp@bsdimp.com> References: <20030416125715.GA12300@falcon.midgard.homeip.net> <20030417005708.D6167@gamplex.bde.org> <20030416172723.GA13575@falcon.midgard.homeip.net> <20030421.020106.41513803.imp@bsdimp.com>
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On Mon, Apr 21, 2003 at 02:01:06AM -0600, M. Warner Losh wrote: > I have a #define in my tree that I switch back and forth from time to > time: > > #if defined(_cplusplus) || !defined(_NULL_VOID) > #define NULL 0L Why not just plain 0? I think either will work fine so it doesn't matter really matter much but I am a bit curious. > #else > #define NULL (void *) 0 Won't work correctly. You need to use ((void*)0) instead with the extra parenthesis. Otherwise expressions like 'sizeof NULL' will fail to compile. > #endif > > and I add -D_NULL_VOID to build when I want to detect problems that > (void *) 0 detects, then switch it back to 0 for the problems that > that detects. > > You can't win here. I'd be inclined to leave things as the status quo. I agree completely with that. -- <Insert your favourite quote here.> Erik Trulsson ertr1013@student.uu.se
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