Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.std.c
Subject: Re: forbidden?  unnecessary?  (was: variable-length struct hack)
Message-ID: <11778@smoke.BRL.MIL>
Date: 9 Dec 89 08:57:32 GMT
References: <448@longway.TIC.COM> <450@longway.TIC.COM> <15364@haddock.ima.isc.com> <4749@fireball.cs.vu.nl>
Reply-To: gwyn@brl.arpa (Doug Gwyn)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 16

In article <4749@fireball.cs.vu.nl> maart@cs.vu.nl (Maarten Litmaath) writes:
>But couldn't an conforming implementation FORBID the (T *) cast?!

No, a conforming implementation is obliged to accept a strictly
conforming application.  It cannot impose its own additional
constraints beyond those spelled out in the Standard.

>	strcpy(p->name = (char *)p + sizeof(T), s);
>If this method is used, copying the struct pointed to by p won't have strange
>effects, as long as *p isn't free()d.  Regarding the struct dirent example
>I'd call that an improvement.

Hardly.  The declared object T does not contain all of the information;
the "name" data lies outside the T object.  This is as bad as the case
that Dennis objected to so far as its usability goes (apart from
linguistic correctness issues).