From:	"Campbell, Rolf [SKY:1U32:EXCH]" <cp1v45 AT americasm01 DOT nt DOT com>
Newsgroups:	comp.os.msdos.djgpp,comp.games.development.programming.misc
Subject:	Re: Compacting the Memory
Date:	Mon, 16 Aug 1999 11:48:43 -0400
Organization:	Nortel Networks
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To:	djgpp AT delorie DOT com
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Ben Davis 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?

    The memory management system with DJGPP does not defragment memory.  But,
don't worry about it, none of the memory really gets wasted.  There may be
blocks of memory temporarily unused, but if you do a small allocation later, it
will likely come from one of those 'wasted' blocks.  Also, remember the
apparent order of memory (from your programs perspective) is not neccesarily
the real order.  The DPMI server will likely page-out those unused memory
blocks to disk if you don't use them for a while and you are allocating more
memory than you physically have.


--
     -Rolf Campbell (39)3-6318

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