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From: dmurdoch@watstat.uwaterloo.ca (Duncan Murdoch)
Newsgroups: comp.sys.ibm.pc.programmer
Subject: Re: No Aliasing Compile Option
Keywords: Microsoft 6.0 C update woes
Message-ID: <1990May29.134523.6261@maytag.waterloo.edu>
Date: 29 May 90 13:45:23 GMT
Article-I.D.: maytag.1990May29.134523.6261
References: <4886@daffy.cs.wisc.edu> <26547195.F69@tct.uucp> <134@qmsseq.imagen.com> <3866@rtifs1.UUCP>
Sender: daemon@maytag.waterloo.edu (Admin)
Organization: University of Waterloo
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In article <3866@rtifs1.UUCP> bcw@rti.rti.org (Bruce Wright) writes:
>In article <134@qmsseq.imagen.com>, pipkins@qmsseq.imagen.com (Jeff Pipkins) writes:
>> 2. It is not "wrong" to use aliasing, either morally or legally, and it is
>> not generally considered bad practice.  Since I used the word "morally",
>> this is obviously my opinion.
>
>I don't know where you've been, but where _I've_ been it _has_ been
>considered bad practice to use aliasing.  Not bad _morally_ or
>_legally_ (how silly) but bad from a program maintenance point of
>view:  it's difficult for someone other than the person who wrote
>the code to understand, correct, and/or modify the code.  Sometimes
>it can even be difficult for the person who wrote it (!).

Is it considered to be aliasing to have two pointers pointing at the same
thing?  This seems to be a very useful and common practice; think about 
having an array sorted in two different ways:  you usually wouldn't want
two copies of the data (especially if you want to modify the entries!), 
you'd probably just want two arrays of pointers into it.  Does this sort
of practice fail when aliasing isn't allowed?

Duncan Murdoch