Article View: comp.std.c++
Article #655Re: Zero-length structures and pointer comparisons
From: Lewis G. Pringle
Date: Tue, 10 Nov 1992 18:52
Date: Tue, 10 Nov 1992 18:52
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1475 bytes
In article <1992Nov4.080805.13496@jyu.fi> sakkinen@jyu.fi (Markku Sakkinen) writes: ... >I would first like to return to a much more important, related problem, >which somebody brought up here rather recently. >Namely, there is nothing in the ARM explicitly saying that >p == q might not yield 1 even when p and q are pointing at two different >objects. This hole makes e.g. some standard idioms in Stroustrup's books >implementation dependent. I'd like to ask a related question. Given code like: char* start = new char [10]; char* end = start+10; char* p = start; assert ((p >= start) && (p <= end)); // this is gauranteed by ANSI-C p += 10; assert ((p >= start) && (p <= end)); // this is gauranteed by ANSI-C p = start; p--; assert (! ((p >= start) && (p <= end))); // ??????? Is the last assertion portable? ARM/ANSI-C References? LeWiS. -- Reading peoples signatures is a real waste of time. lewis@sophists.com (Lewis Gordon Pringle, Jr.)
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Newsgroups: comp.std.c++ Path: arc1-ca.pugleaf.net!sparky!uunet!think.com!sophists.com!lewis From: lewis@sophists.com (Lewis G. Pringle) Subject: Re: Zero-length structures and pointer comparisons Message-ID: <1992Nov10.185247.14128@sophists.com> Date: Tue, 10 Nov 1992 18:52:47 GMT References: <1992Oct28.184135.25475@ucc.su.OZ.AU> <1992Oct30.003946.10484@microsoft.com> <1992Nov4.080805.13496@jyu.fi> Organization: Sophist Solutions Lines: 35