Date: Sun, 26 Feb 1995 22:00:33 -0500 (CDT)
From: Aaron Ucko <UCKO AT VAX1 DOT ROCKHURST DOT EDU>
Subject: Re: topline
To: OKRA AT max DOT tiac DOT net
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Organization: Rockhurst College; Kansas City, MO

>  Is it me or is topline not updated when I free something?
>  I was concerned that my program seemed to be taking 3 times as much 
>memory as it should, so I traced through it to make sure it was calling 
>free.  It was, but topline didn't change.
>  This is how my program seems to go:
>
>  malloc 230k      - topline goes up 475k
>  free 50k         - topline stays where it is
>  malloc 77k       - topline goes up 120k
>  free 77k         - topline stays where it is
>
>  Obviously at least some of this is still my fault.  But I was _there_
>when it free'ed memory - I _saw_ it happen... and topline didn't do
>anything at all.  It just sat there, letting all this innocent memory get 
>massacred.  How can I stand by and watch this atrocity?  Please, someone, 
>help me end this!

`free'd memory, I believe, is generally not returned directly to the
system, but rather marked to your program as free and used by malloc
preferentially over `new' memory, so you shouldn't expect topline to
change after calls to free; however, if you malloc something, free it,
and then malloc something of the same size or smaller, your program's
memory footprint should not change after the initial malloc.


--- Aaron Ucko (ucko AT vax1 DOT rockhurst DOT edu; finger for PGP public key) -=- httyp!
-=*=-Just because you're paranoid doesn't mean they aren't out to get you.-=*=-
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