Date: Fri, 30 Mar 2001 10:04:45 +0200 (CEST) From: Harti Brandt <brandt@fokus.gmd.de> To: Alfred Perlstein <bright@wintelcom.net> Cc: Peter Seebach <seebs@plethora.net>, Todd Whitesel <toddpw@best.com>, <tech-kern@netbsd.org>, <freebsd-hackers@FreeBSD.ORG> Subject: Re: Question regarding the array of size 0. Message-ID: <Pine.BSF.4.33.0103301000020.476-100000@beagle.fokus.gmd.de> In-Reply-To: <20010329235022.W9431@fw.wintelcom.net>
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On Thu, 29 Mar 2001, Alfred Perlstein wrote:
AP>* Peter Seebach <seebs@plethora.net> [010329 23:49] wrote:
AP>> In message <200103300647.WAA25263@shell17.ba.best.com>, Todd Whitesel writes:
AP>> >Just put a 1-element array at the end of your header struct, and account for
AP>> >it when you work out how much extra space to allocate. C memory layout rules
AP>> >guarantee that this usage will have the desired effect.
AP>>
AP>> Nope, not portable. The implementation is allowed to bust you for
AP>> overstepping the bounds of the array. :)
AP>>
AP>> The only portable solution is the new feature in C99.
AP>
AP>Which new feature?
struct foo {
double bar;
int baz[];
};
I suppose. But neither gcc nor Sun-cc seem to support it :-(
# gcc -c x.c
x.c:3: field `baz' has incomplete type
# cc -c x.c
"x.c", line 3: null dimension: baz
cc: acomp failed for x.c
Well, that's even lesser portability.
struct foo {
double bar;
int baz[0];
};
works for both compilers.
--
harti brandt, http://www.fokus.gmd.de/research/cc/cats/employees/hartmut.brandt/private
brandt@fokus.gmd.de, harti@begemot.org
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