From: Kovacs Viktor Peter <vps AT winnie DOT obuda DOT kando DOT hu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Run djgpp program in real dos got SIGSEGV signal ?
Date: Wed, 26 Sep 2001 11:26:27 +0200
Organization: Budapest University of Technology and Economics
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[On Tue, 25 Sep 2001, Chunfeng Zhao wrote:]
> Hi,
> I am trying to use DJGPP to compile a DOS program to access the graphic
> frame buffer and registers, when I run the program in a DOS box from Windows
> 98, it runs okay, but after I reboot the system into real DOS mode, it give
> the SIGSEGV singal and exit the program. Can any one help me out on this ?
> Thanks!

 You are probably referencing memory outside your allocated memory area.
 (like hw. memory, non dpmi memory /low memory/)

 Under the windows dpmi all segments have a limit of 4Gb. Dos based
 dpmi servers limit the segments to the allocated ram. You have to
 turn on 'near' pointer support. (see: near and far pointer support
 in the djgpp manual) This can fail with some extenders. It works
 with cwsdpmi and tran's pmode extender. These funtions modify the
 segment limits in the descriptors. (the segment bases can change)

   Viktor