Xref:	news2.mv.net comp.os.msdos.djgpp:6781
From:	C M Marka <matriu AT gim DOT ktu DOT lt>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Flat Memory Questions
Date:	Sat, 3 Aug 1996 16:22:52 +0000
Organization:	LITNET
Lines:	28
Message-ID:	<Pine.HPP.3.91.960803160943.7717A-100000@santaka.sc-uni.ktu.lt>
References:	<720 DOT 9607281807 AT ws-ai5 DOT dur DOT ac DOT uk>
NNTP-Posting-Host:	santaka.sc-uni.ktu.lt
Mime-Version:	1.0
In-Reply-To:	<720.9607281807@ws-ai5.dur.ac.uk>
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

On Sun, 28 Jul 1996 Sengan DOT Short AT durham DOT ac DOT uk wrote:

> 
> char Array[1024*1024];
> void main ( void )
> { ... }
> Array is now static: ie a 1Mb array is made inside your executable, working
> but leading to a bloated >1Mb executable!       ^^^^^^^^^^^^^^^^^^^^^^
>                      ^^^^^^^^^^^^^^^ 
> Third choice: malloc: dynamic, no disadvantages.
>                                ^^^^^^^^^^^^^^^^

Wrong!

[1] Static stuff is put to the .bss section, which is allocated by the
    DJGPP stub a loadtime. You can define a 16 meg static array and there
    will be *absolutely* mo exec size overhead.

[2] malloc() from DJGPP C library only allocates blocks of sizes 2^n
    (for speed reasons). i.e., if you do malloc(1025), it actually
    allocates 2048 (2^11) and the rest (1023 minus some internal malloc
    structures) gets wasted. Ain't that a disadvantage? The only 
    advantage is that you can catch a malloc() failure. In static array 
    case, the program just would not load, exiting with an error message.

Martynas

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