Date: Thu, 22 Aug 2002 22:31:01 +1000 (EST) From: Bruce Evans <bde@zeta.org.au> To: Garrett Wollman <wollman@lcs.mit.edu> Cc: archie@dellroad.org, <arch@FreeBSD.ORG> Subject: Re: NULL Message-ID: <20020822221905.H3508-100000@gamplex.bde.org> In-Reply-To: <200208220245.g7M2jD8A004461@khavrinen.lcs.mit.edu>
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On Wed, 21 Aug 2002, Garrett Wollman wrote: > In article <200208212358.g7LNw8l08243@arch20m.dellroad.org> you write: > >Seems like the same is true of "0".. e.g., suppose that pointers > >are larger than integers, and you call a variadic function with > >"NULL" as one of the extra parameters: > > > > printf("foo=%p num=%d\n", NULL, 123); > > > >This would get screwed with NULL=0 but work right with NULL=(void *)0. > > That's a feature. (Unfortunately, this feature is not implemented on > ILP32 architectures. Is 0LL allowed as a null pointer constant? That > would break everyone equally in this case.) I think it is not implemented on many I32LP64 arches either, since most arches with 64-bit pointers have pass all args as 64-bit. Everything between ((signed char)0) and ((uintmax_t)0) is allowed. uintmax_t would have to be > 64 bits to break the 64-bit arches equally. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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