Arrays failing to work

[Bri Rock]

Hi all,

I'm having a huge issue over a simple problem. I'm trying to initialize two arrays which are fairly large.

#include <stdio.h>
#include <stdlib.h>

int main()
{

 unsigned short Projections[336][265][283];
 unsigned short Michelogram[18][18][336][283];

 printf("\n-=<This program ran successfully>=-\n\n");

 return 0;

}

This compiles fine, but when I run it, I get:
Segmentation fault (core dumped)

I've been compiling this snippet on gcc 3.3.2 in Red Hat Linux Fedora core 1. I haven't compiled this on Windows Bloodshed Dev-C++ yet.

What confuses me is that this code below works:

#include <stdio.h>
#include <stdlib.h>

int main()
{

 /*unsigned short Projections[336][265][283]; */
 unsigned short Michelogram[18][18][336][40];

 printf("\n-=<This program ran successfully>=-\n\n");

 return 0;
}

By getting rid of one array, and toning down the other, it works.

It's almost as if these arrays have a maximum size, or something to that effect. At first, I thought this was a memory issue. The computer I'm running it on is a P3 300MHz w/ 128MB SDRAM. I compiled it on a Dual Xeon 2.4GHz with more RAM, but I still got the same error.

Anyone else have this problem?

Any suggestions would be extremely helpful.

Cheers,
Bri Rock

[chrismiceli]

Linux limits the amount of memory one user can use, try it as root, if it still doesn't work, you know that is not the problem because root has not memory restrictions. If it does, you need to edit something in /proc (can't remember offhand) that changes the rlimit of the memory max a user can have.

[hk_mp5kpdw]

You may be exceeding the maximum stack size. You can try allocating your memory dynamically... or putting the array declarations above the main function to make it global. Assuming 16-bit shorts and no math mistakes on my part, the Projections takes up 48 Megs of space and Michelogram takes up 58 Megs.

I ran your initial code under MSVC++ 6.0 and it complied and linked fine but bombed out. Moving the array declarations above the main function like I said fixed the problem.

[Salem]

You could always make them static, if you also want to preserve the scope as well.

[Bri Rock]

Hey guys,

Thank you very much for all the sugesstions!

All of these solutions worked.

The full program now works great. Thanks again, and maybe I can help out in return for the favor.

Cheers,
Bri Rock