Mail Archives: djgpp/1999/03/01/08:18:45

Date: Mon, 1 Mar 1999 11:41:47 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender: eliz AT is
To: Kevin Lang/Ultima <ultima AT game-master DOT com>
cc: djgpp AT delorie DOT com
Subject: Re: Help! (Program Crashes)
In-Reply-To: <>
Message-ID: <Pine.SUN.3.91.990301113905.2578Z-100000@is>
MIME-Version: 1.0
Reply-To: djgpp AT delorie DOT com

On Sun, 28 Feb 1999, Kevin Lang/Ultima wrote:

> I don't understand why it crashes..

Did you try the methods of debugging suggested by section 12.2 of the
DJGPP FAQ list?  If not, please try those which are applicable to this

> AFAIK I put all NULL checks and all that.

Your crash is not because of NULL pointer dereference (Windows cannot
detect those); it's a GPF.  Section 12.2 of the FAQ explains what
problems can cause a GPF.  Just from looking at the registers' dump,
the value of EDX (7F7F7F7Fh) seems highly suspicious, but only poking
around the code in a debugger can tell whether it is at all relevant
to the problem.

> It crashes in either DOS or WINDOWS.

The crash you posted is on Windows, I think.  If the crashes on DOS
look even slightly different, especially if they point to a different
location, post them as well.

> Here is the crash I get:
> Shutting down Allegro
> Exiting due to signal SIGSEGV
> General Protection Fault at eip=0000504a
> eax=00120508 ebx=00120508 ecx=00000409 edx=7f7f7f7f esi=00000054
> edi=000879f8
> ebp=001079b4 esp=001079ac program=C:\DETECT~1\SOURCE\ISO\EX0.EXE
> cs: sel=00a7  base=828e3000  limit=00b4ffff
> ds: sel=00af  base=828e3000  limit=00b4ffff
> es: sel=00af  base=828e3000  limit=00b4ffff
> fs: sel=00bf  base=00000000  limit=0010ffff
> gs: sel=00bf  base=00000000  limit=0010ffff
> ss: sel=00af  base=828e3000  limit=00b4ffff
> App stack: [001079f8..000879f8]  Exceptn stack: [000878d0..00085990]
> Call frame traceback EIPs:
>   0x0000504a   _add_sprite_to_end+46, line 46 of spr_list.c
>   0x00002d6a   _main+5962, line 144 of ex0.c
>   0x00032426   ___crt1_startup+174

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