From: "A. Sinan Unur" <asu1 AT cornell DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: DJGPP MEM BUG?  -- NOT
Date: Sun, 15 Jun 1997 12:11:28 -0400
Organization: Cornell University http://www.cornell.edu
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Jawed Karim wrote:
> 
> I really need the following code to work. Under Linux, this works
> PERFECTLY. Under DJGPP I get SIGSEVs every single time. See for
> yourself:
> 
> --
> #include <stdio.h>
> 
> typedef struct {
>         int r, g, b;
>         int closest_fit;
> } Table;

let's see, sizeof(Table) is 16.

> 
> main()
> {
>         Table thingy[255][128];
> }
> ---

you are asking for 255*128*16 = 510 K of memory from the stack. AFAIK,
djgpp programs have a default stack size of 256 K. you can use the
program stubedit in you bin directory to change this value. that said, i
do not think it is a good idea to allocate so much memory from the
stack.


> It doesnt crash with [255][32] but it does with [255][64]. In any 
> case, even with 128 it SHOULD NOT. It's not that much memory, and 

because with 32, you are asking for 127.5 K and with 64 K, you are
asking for 255 K. it is not that much memory to allocate on the heap,
but not when it comes to the stack.

> under linux gcc it works. Any ideas? 

so, under linux, the default stack size must be larger.

> Please email me directly...

will do. however, i would appreciate it if you do not do the same. i can
read the newsgroup fine.

BTW, if you look at the trace, it tells you

> Stack Fault at eip=00001559

i would urge everyone to first think before blaming djgpp, cwsdpmi etc
for all their woes.
-- 
   Sinan
 
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