From:	terra AT diku DOT dk (Morten Welinder)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: windows <-> cwsdpmi
Date:	23 Dec 1996 20:27:05 GMT
Organization:	Department of Computer Science, U of Copenhagen
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Sender:	terra AT tyr DOT diku DOT dk
Message-ID:	<59mpup$csp@vidar.diku.dk>
References:	<851364688 DOT 618879 DOT 0 AT abwillms DOT demon DOT co DOT uk>
NNTP-Posting-Host:	tyr.diku.dk
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

"Alaric B. Williams" <alaric AT abwillms DOT demon DOT co DOT uk> writes:

>Conservative GC can be used in C. It works like so:

You cannot garbage collect in C unless you restrict the class
of valid programs.

Consider:

-----------------------------------------------------------------------------
m = malloc (...);
<fill something into m's data area>
<print m's address to a file, possibly using fprintf's %p>
m = 0;
...
<let garbage collection happen here>
...
<reread m's address>
<access m's data area>
-----------------------------------------------------------------------------

There is no way that the garbage collector could know that m's data
area was pointed to by something in a file.

But all this should not be taken to mean that a garbage collector
used in connection with C can not be useful.  This is just theory.

Morten

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