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From: jimad@microsoft.com (Jim Adcock)
Subject: Re: Zero-length structures and pointer comparisons
Message-ID: <1992Oct19.184858.16873@microsoft.com>
Date: 19 Oct 92 18:48:58 GMT
Organization: Microsoft Corporation
References: <1992Sep10.094957.23588@jyu.fi> <1992Oct16.234851.28948@microsoft.com> <23915@alice.att.com>
Lines: 21

In article <23915@alice.att.com> ark@alice.UUCP () writes:
|In article <1992Oct16.234851.28948@microsoft.com> jimad@microsoft.com (Jim Adcock) writes:
|
|> But in any case, at least my PC compiler (Large Model)
|> performs == and != comparisons based both on the segment and offset parts.
|> Its the ordered comparisons > < >= <= where only the offset part is compared.
|> Thus == != work for all ptrs.  > < >= <= only work within an array.
|
|> Which is as it should be.
|
|This is far from clear.
|
|For example, if a type T has a < operator defined that is actually a strong
|total order relation, that makes it possible to store T objects efficiently
|in a variety of order-based data structures such as M,N-trees, etc.
|There are many applications for such structures.  For example, one might make
|the constructor and destructor for class T use such a structure to keep
|track of all the T objects in the universe, and so on.

Are you talking about overloadable comparison operators?  I am talking
about built-in ptr comparison operators as defined by C/C++