Message-ID: <3AC1609C.A537E890@earthlink.net>
From: Martin Ambuhl <mambuhl AT earthlink DOT net>
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Newsgroups: comp.os.msdos.djgpp
Subject: Re: Hunting Sigsev Errors
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Date: Wed, 28 Mar 2001 03:51:50 GMT
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To: djgpp AT delorie DOT com
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Greg Donnells wrote:
> 
> Well, I've discovered something interesting regarding SIGSEV errors and gcc
> (2.953). Consider the following code fragment:

[compileable version with results below]

> 
> This code fragment will ALWAYS generate a SIGSEV before the LOG call. If it
> doesn't - I get real strange behavior out of the fread() function call.
> Changing the ARRAYSIZE to 512 fixes this - no more SIGSEV and no more wierd
> behavior out of fread(). Looks like some sort of allocation bug or internal
> limit is being reached (1024x516= ~.5M, but 512x516=~.25M).
> 
> NOTE: The rest of the above program is another 50 lines of C code - that's
> all - no subroutines, etc. Just a main() module.

I cannot reproduce your error:
#include <stdio.h>
#include <string.h>

#define LOG(a,b) fprintf(stderr, a, b);
#define ARRAYMAX 1024
#define NUL (char)0

int main(int argc, char *argv[])
{
    FILE *ifp, *ofp;
    int i, p;
    char *pos, *j;

    struct hdr {
        char cbs[4];
        long start;
        long last;
    } cbs_hdr;

    struct rec {
        long index;
        char fname[512];
    } allrecs[ARRAYMAX];

    LOG("Starting with argc = %d\n", argc);
    return 0;
}


$gcc -O3 -W -Wall -ansi -pedantic a.c 2>a.e
$gcc -v
Reading specs from c:/djgpp/lib/gcc-lib/djgpp/2.953/specs
gcc version 2.95.3 20010315/djgpp (release)
$./a    
Starting with argc = 1
$./a foo
Starting with argc = 2
$./a foo bar
Starting with argc = 3