From:	frazer AT rtp DOT ericsson DOT se (Scott Frazer)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: emacs 19.34 crashes immediately on win nt 4.0
Date:	Wed, 05 Mar 1997 16:34:44 GMT
Organization:	Ericsson Data Services Americas
Lines:	82
Message-ID:	<331d9fbf.1804608@cnn.exu.ericsson.se>
References:	<Pine DOT SUN DOT 3 DOT 91 DOT 970227183648 DOT 2124A-100000 AT is>
NNTP-Posting-Host:	pc093.rtp.ericsson.se
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Eli Zaretskii <eliz AT is DOT elta DOT co DOT il> wrote:

>Before we conclude that the NT DPMI host has a bug, please try to put
>a reasonable value into info.size, so we know that it doesn't puke
>because the garbage there seems like you are asking for too much DOS
>memory.
>
>Also, try to compile the program with the Unixy sbrk (that's how Emacs
>is built) and see if that makes any difference.

Okay, here's the new test.c:

/* test.c */

#include <crt0.h>
#include <dpmi.h>

int _crt0_startup_flags = _CRT0_FLAG_UNIX_SBRK;

int main( void )
{
  _go32_dpmi_seginfo info;

  info.size = 4;
  _go32_dpmi_allocate_dos_memory ( &info );
  _go32_dpmi_free_dos_memory ( &info );

  return( 0 );
}

compile and run:

C:\test\emacs>gcc -Wall -g -o test.exe test.c

C:\test\emacs>gdb test.exe
GDB is free software and you are welcome to distribute copies of it
 under certain conditions; type "show copying" to see the conditions.
There is absolutely no warranty for GDB; type "show warranty" for
details.
GDB 4.16 (go32), Copyright 1996 Free Software Foundation, Inc...
(gdb) break main
Breakpoint 1 at 0x155b: file test.c, line 12.
(gdb) run
Starting program: c:/test/emacs/test.exe

Breakpoint 1, main () at test.c:12
12        info.size = 4;
(gdb) step
13        _go32_dpmi_allocate_dos_memory ( &info );
(gdb) step
14        _go32_dpmi_free_dos_memory ( &info );
(gdb) nexti
0x1571  14        _go32_dpmi_free_dos_memory ( &info );
(gdb) nexti
0x1572  14        _go32_dpmi_free_dos_memory ( &info );
(gdb) nexti

Program received signal SIGSEGV, Segmentation fault.
0x346b in _get_volume_info ()
(gdb) info all-registers
eax            0x257    599
ecx            0x4a288  303752
edx            0x257    599
ebx            0x4d320  316192
esp            0x3542   0x3542
ebp            0x43548  0x43548
esi            0xd7     215
edi            0xa2d4   41684
eip            0x346b   0x346b
ps             0x13256  78422
cs             0xc7     199
ss             0xb7     183
ds             0xb7     183
es             0xd7     215
fs             0x217    535
gs             0x24f    591
(gdb)

The same thing happens ( can't vouch for the registers
obviously ) without the Unixy sbrk.

Scott

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