Article View: comp.std.c
Article #6124Re: "expandable" structs with last element declared using [1]
From: Sean Fagan
Date: Tue, 19 Dec 1989 09:55
Date: Tue, 19 Dec 1989 09:55
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2077 bytes
In article <468@bbxsda.UUCP> scott@bbxsda.UUCP (Scott Amspoker) writes:
>In article <477@longway.TIC.COM> uunet!sq!msb (Mark Brader) writes:
>I believe Doug has
>>stated that there are implementations where it doesn't work, but hasn't
>>named any. Can someone do so (in comp.lang.c)?
>
>Maybe someone thinks that structure fields need not be allocated in
>any particular order. I wouldn't be surprised if it didn't work on
>some system somewhere, but such a system is probably at fault.
*sigh* Think: you have a structure that looks like
struct foo {
int size;
char name[1];
};
Now, if you're doing symbolic debugging, the information gets encoded as
something like:
structure <name: foo> <elements: 2>
integer <name: size>
array <name: name> <size: 1>
char
or somesuch. Now, imagine an architecture that does that in hardware (well,
microcode, probably). Guess what, there *are* machines that do! Most LISP
machines do something similar, and there are other machines that can do it
(I'm sure a Burroughs machine can, since they can do everything else 8-)).
Turning on bounds-checking in your compiler, if it supported it, would cause
it to fail.
So, nope, the implementation is *not* at fault. There are some good reasons
for not making it valid (although I believe they can all be gotten around
somehow), and not only having to do with interpreters.
--
Sean Eric Fagan | "Time has little to do with infinity and jelly donuts."
seanf@sco.COM | -- Thomas Magnum (Tom Selleck), _Magnum, P.I._
(408) 458-1422 | Any opinions expressed are my own, not my employers'.
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!sco!seanf From: seanf@sco.COM (Sean Fagan) Newsgroups: comp.std.c Subject: Re: "expandable" structs with last element declared using [1] Message-ID: <4171@scolex.sco.COM> Date: 19 Dec 89 09:55:32 GMT References: <UZTerlu00VcJEDulRd@andrew.cmu.edu> <463@cpsolv.UUCP> <477@longway.TIC.COM> <468@bbxsda.UUCP> Reply-To: seanf@sco.COM (Sean Fagan) Organization: The Santa Cruz Operation, Inc. Lines: 40