From: Gary Leavens <leavens AT cs DOT iastate DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Bohem-Demers-Weiser garbage collector (gc) with C++ under DJGPP
Date: Fri, 06 Jun 1997 12:59:06 -0500
Organization: Department of Computer Science, Iowa State Univ.
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Message-ID: <33984FEA.57ED@cs.iastate.edu>
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Peter Monks wrote:
> 
> In article <33973FC7 DOT 67A6 AT cs DOT iastate DOT edu>, Gary Leavens <leavens AT cs DOT iastate DOT edu> wrote:
> >What happens is that when I run C++ programs with the gc interface,
> >I get messages like:
> >
> > Abort!
> > STACK_GROWS_DOWN is defd, but stack appears to grow up
> > sp = 0x198f48, GC_stackbottom = 0xc0174
> > stack direction = 3
> 
> I had the same problem with C programs that use the Boehm-Demers-Weiser gc.
> The problem seems to be that the stack for a DJGPP program is not necessarily
> located at the same place in memory each time the program is run, which is an
> assumption the default gc makes.
> 
> The gc documentation describes a way to get around this, though.  Look in
> readme.dj and config.h for details.
> 
> Basically, you have to declare a dummy local variable in your main function,
> and then point GC_stackbottom at it.  After doing this, I had no problems with
> the garbage collector's basic functionality.

Thanks for the help. I tried this, but unfortunately it still doesn't
work.
Now I get messages that are slightly different, but still of the same
kind...

 Abort!
 STACK_GROWS_DOWN is defd, but stack appears to grow up
 sp = 0xfffacf48, GC_stackbottom = 0xc0b74
 stack direction = 3

Perhaps the problem is that sp is wrapping around to negative numbers?
I'm not sure.  Any help would be appreciated.


	Gary Leavens