NNTP-Posting-Host: 172.16.26.200
Newsgroups: comp.os.msdos.djgpp,comp.games.development.programming.misc
Date: Mon, 23 Aug 1999 11:50:38 +0200
Message-ID: <0E16861EE7BCD111BE9400805FE6841F0B116B91@c1s5x001.cor.srvfarm.origin-it.com>
From: bas DOT hamstraNOSPAM AT nl DOT origin-it DOT com (Bas Hamstra)
Subject: Re: Compacting the Memory
References: <7p974q$4gg$1 AT news6 DOT svr DOT pol DOT co DOT uk>
X-Newsreader: Forte Free Agent 1.0.82
Lines: 38
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

I can fully confirm this experience. I used a database whith chess
positions. A lot of records were inserted and deleted. 

In DOS days, when you had 100kb and freed 10 kb, you automatically had
110 k free RAM. Under Win this is not necessarily the case, due to
memory fragmentation. I noticed this with *all* compilers under win.

If you want to avoid this I m afraid you have to write your own mem
mgt routines. For example alloc larger chunks of mem normally and
manage allocs/free's on record-level yourself.


Regards,
Bas Hamstra.











"Ben Davis" <ben AT vjpoole DOT freeserve DOT co DOT uk> wrote:

>I am writing a program in DJGPP C, which uses the memory VERY dynamically:
>there are loads of malloc()s and free()s. They occur in a strange order, and
>some are quite large. If two blocks are allocated, and then the first one is
>freed, and then a third, larger block is allocated before the second one is
>freed, some memory is wasted (I fear).
>What I would like to know is, does DJGPP automatically compact the memory by
>moving blocks down to fill all the gaps, or do I have to do it manually? How
>can I do this?