Path: utzoo!attcan!uunet!ateng!chip
From: chip@ateng.uucp (Chip Salzenberg)
Newsgroups: comp.lang.c
Subject: array[-1] -- permitted?
Message-ID: <1988Sep19.164701.11136@ateng.uucp>
Date: 19 Sep 88 20:47:01 GMT
References: <867@osupyr.mast.ohio-state.edu> <3200@geac.UUCP> <1430@ficc.uu.net> <1988Sep15.145026.20325@ateng.uucp> <16041@ism780c.isc.com>
Reply-To: chip@ateng.UUCP (Chip Salzenberg)
Organization: A T Engineering, Tampa, FL
Lines: 20

According to news@ism780c.isc.com:
>But consider what might have happened had dpANS mandated that the compution
>of a pointer to x[-1] be a valid operation.

Okay, let's imagine:  X3J11 says that x[-1] must be valid.
	       then:  int must be 32 bits.
	       then:  address space must be linear.
	       etc. until only the SPARC is conforming.  (no smileys here)

Each time you make a "beneficial" restriction, you're condemning present
users of real, useful computers to the purgatory of enforced non-
conformance.  I don't think anyone really wants X3J11 to make decisions
about which hardware will be permitted to run C programs.

In addition, it should be observed that on this issue, X3J11 stuck to its
charter and codified existing practice.
-- 
Chip Salzenberg                 or 
A T Engineering                My employer may or may not agree with me.
	  The urgent leaves no time for the important.