Message-Id: <3.0.1.32.19970722035329.0069bfd4@postoffice.tidalwave.net>
Date: Tue, 22 Jul 1997 03:53:29 -0400
To: mailto:
From: Kenn White <kennw AT tidalwave DOT net>
Subject: Weird static/dynamic allocation crash...
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Hello DJGPP gurus.

Here's a strange one for you.

I'm having trouble with the *very* simple program below.
It seems that when the integer x is forceably set (i.e.,
statically allocated), I get a run-time crash.  When
is is malloced, however, everything is fine.

I have tried changing the command.com /e: to as high as 32768,
with no luck.


Any ideas?

Kenn White
kennw AT tidalwave DOT net


System: Gateway P-120 w/ 24MB RAM, Windows 95 full-screen DOS Window
DPMI memory available: 17447 Kb
DPMI swap space available: 4113 Kb
TMP=C:\WINDOWS\TEMP
TEMP=C:\WINDOWS\TEMP
PROMPT=$p$g
winbootdir=C:\WINDOWS
COMSPEC=C:\COMMAND.COM
PATH=C:\WINDOWS;C:\WINDOWS\COMMAND;C:\;C:\NORTON95;C:\DJGPP\BIN;
SOUND=c:\CREATIVE
MIDI=SYNTH:1 MAP:E MODE:0
DJGPP=C:\DJGPP\DJGPP.ENV
windir=C:\WINDOWS
BLASTER=A220 I5 D1 H5 P330 T6 E620


********************************************
#include<stdlib.h>
#include<stdio.h>
#define SIZE 1000000
#define STRANGE

int main(void) {

#ifdef STRANGE
 int a, x[SIZE];
#endif

#ifndef STRANGE
 int a, *x;
 x=malloc(SIZE*sizeof(int));
 if (x==NULL) {
    printf("Malloc fail.\n");
    exit(0);
  }
 printf("Passed malloc \n");
#endif

for (a=0; a<SIZE; a++)
 x[a]=a;
printf("Finished loop fill. \n");
return 0;
}

***************************************************************
This is the output when x is set statically (STRANGE defined):
****************************************************************

C:\32c>q

Exiting due to signal SIGSEGV
Stack Fault at eip=00001571
eax=00000000 ebx=00142160 ecx=00000000 edx=0000033e esi=00000054 edi=0000c4d0
ebp=0013ffd4 esp=ffd6f6d0 program=C:\32C\Q.EXE
cs: sel=00a7  base=82b86000  limit=0014ffff
ds: sel=00af  base=82b86000  limit=0014ffff
es: sel=00af  base=82b86000  limit=0014ffff
fs: sel=0087  base=0000bfb0  limit=0000ffff
gs: sel=00bf  base=00000000  limit=ffffffff
ss: sel=00af  base=82b86000  limit=0014ffff

Call frame traceback EIPs:
  0x00001571


*********************************************************************
This is the output with dynamic allocation (STRANGE commented out)
*********************************************************************

C:\32c>q
Passed malloc
Finished loop fill.