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Message-ID: <50A0022C.9030406@gmx.de>
Date: Sun, 11 Nov 2012 20:53:16 +0100
From: Juan Manuel Guerrero <juan DOT guerrero AT gmx DOT de>
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To: Eli Zaretskii <eliz AT gnu DOT org>
CC: djgpp AT delorie DOT com
Subject: Re: Difficulties using DJGPP 2.04 together with DOSLFN 0.41 on MSDOS
 6.22
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Am 11.11.2012 19:49, schrieb Eli Zaretskii:
>> Date: Sun, 11 Nov 2012 18:42:34 +0100
>> From: Juan Manuel Guerrero <juan DOT guerrero AT gmx DOT de>
>>
>> I have tried to compile a simple "hello world" like program.  I have used MSDOS 6.22
>> together with DOSLFN 0.41 (used options  ~- t+; this means that no numeric tail
>> will be created).  I have used djdev204, gcc472b, bnu223b and CWSDPMI r7 without
>> activated swap file.  The system has 64 MB.  The program crashes with the
>> following stack trace:
>>
>>     Stack Fault at eip=1902d; flags=3293
>>     eax=11000000 ebx=00000000 ecx=00000000 edx=00000000 esi=4f575c3a edi=4407712f
>>     ebp=415c4b52 esp=00000781 cs=e7 ds=ef es=ef fs=cf gs=0 ss=cf error=0000
>>
>>
>> It makes no difference if I use gcc471b and bnu222br4.  It crashes in the same
>> way.  If I try to debug the program, I get the following output:
>>
>>     GNU gdb (GDB) 7.5
>>     [snip]
>>     Reading symbols from d:/work/a.exe...Dwarf Error: wrong version in compilation
>>     unit header (is 0, should be 2, 3, or 4) [in module d:/work/a.exe]
>>     (gdb) q
> Does GDB say that even if you remove DOSLFN, reboot, and then try
> debugging the program?  If so, I'd suspect file I/O functions that
> somehow write corrupted data to the executable.

Yes, GDB says the same even if I remove DOSLFN and reboot the system.
Also the program continues crashing if I reemove DOSLFN and reboot the
system.  The only way to get a program that does not crash and that can
be debuged with GDB is to recompile the code with DOSLFN deinstalled.


> One way to dig into this would be to run objdump on the binary
> compiled with DOSLFN, then on the same program compiled without
> DOSLFN, and compare the results.
>
> Once you've established that file I/O under DOSLFN is the problem, I'd
> try disabling the LFN DOS calls in functions like _write and see if
> that helps.  Or maybe diff the sources of v2.04 against v2.03, and see
> which functions had changes in the LFN parts -- this could give you
> ideas what functions could trigger a bug in DOSLFN.
>
> Yes, it's a large job, sorry.
>
Yes, I will follow this strategy, but it make take same time until I will have fixed this

Regards,
Juan M. Guerrero