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From: ok@goanna.cs.rmit.edu.au (Richard A. O'Keefe)
Subject: Re: Coding for Obscurity
Date: 1997/11/24
Message-ID: <65b6ns$kok$1@goanna.cs.rmit.edu.au>#1/1
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Organization: Comp Sci, RMIT University, Melbourne, Australia.
NNTP-Posting-User: ok
Newsgroups: comp.lang.ada,comp.lang.c,comp.lang.c++
Date: 1997-11-24T00:00:00+00:00
List-Id: <comp.lang.ada>


Stephan Wilms <Stephan.Wilms@CWA.de> writes:
>In detail: I would reqrite the first example like this:

>    /* Sensible comment about what get's allocated. */
>  if ( to == NULL )
>  {
>    to = malloc( sizeof *to);
>    if ( to == NULL ) return NULL;
>  }

I would be rather unhappy at _any_ of these being common in my C code.
One thing I would very much like to have in C is a '* __nonnull__' form.
One thing I love about LC-Lint is that it distinguishes between
	sometype *p;		/* p should not be null */
	sometype */*@null@*/ q;	/* q may or may not be null */

The reason that I dislike the C fragment above is that when you are forced
to do manual memory management, you have to be absolutely clear about who
`owns' a dynamically allocated object and who doesn't.  This fragment
muddies that up.  If you could specify in the interface that to _couldn't_
be NULL on entry, then you wouldn't have to patch around the problem at
run time.

By the way, I regard this as a defect in Ada as well.  Ada was supposed to
allow for garbage collection, but with the exception of a couple of recent
Ada->JVM compilers, this hasn't happened.  Since you _do_ have to do manual
memory management in practice, it is a pity that the language doesn't provide
more compile-time help for getting it right.  Perhaps Ada 2007 could borrow a
few ideas from LC-Lint.
-- 
John �neas Byron O'Keefe; 1921/02/04-1997/09/27; TLG,TLTA,BBTNOTL.
Richard A. O'Keefe; RMIT Comp.Sci; http://www.cs.rmit.edu.au/%7Eok