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From: rang@cs.wisc.edu (Anton Rang)
Newsgroups: comp.sw.components
Subject: Re: Real-time Garbage Collection
Message-ID: <RANG.89Sep18160502@derby.cs.wisc.edu>
Date: 18 Sep 89 21:05:02 GMT
References: <1895@hydra.gatech.EDU> <6493@hubcap.clemson.edu>
Sender: news@spool.cs.wisc.edu
Organization: UW-Madison CS department
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In-reply-to: billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu's message of 18 Sep 89 17:41:43 GMT

In article <6493@hubcap.clemson.edu> billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu (William Thomas Wolfe, 2847 ) writes:
>From article <1895@hydra.gatech.EDU>, by tynor@prism.gatech.EDU (Steve Tynor):
>> Freeing the memory _is_ usually straightforward. Knowing when it's safe to 
>> do so _isn't_. That's when GC (or reference counting) becomes necessary.
>
>   It's safe to do so:
>
>     1) When the variable goes out of scope
>
>     2) When the programmer specifies that it's to be destroyed sooner.

  If there's any explicit pointer manipulation, these conditions
aren't sufficient, because an object can be pointed to in more than
one place.  For instance, if I have two objects (A and B) sharing
pointers to object X, then object X should be destroyed (assuming no
other references) when both A and B have been destroyed.
  Personally, I prefer controlling my own data structures...leaving it
up to a garbage collector has always seemed a little sloppy to me.
   
+----------------------------------+------------------+
| Anton Rang (grad student)        | "VMS Forever!"   |
| University of Wisconsin--Madison | rang@cs.wisc.edu |
+----------------------------------+------------------+