Date: Thu, 28 Jun 2001 22:24:36 +0300
From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>
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To: djgpp AT delorie DOT com
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Subject: Re: Peculiar behavior of program.
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> From: invalid AT erehwon DOT invalid (Graaagh the Mighty)
> Newsgroups: comp.os.msdos.djgpp
> Date: Thu, 28 Jun 2001 15:11:52 GMT
> 
> >> That suggests to make such a scheme be used when code is compiled with
> >> -g and not -fomit-frame-pointer.
> >
> >The problem is, -fomit-frame-pointer is a compiler switch, while the
> >setup of the runtime environment is done in the library.  How will the
> >library startup code know that -fomit-frame-pointer was used or not?
> 
> That's easy. What decides what file to use to link in the standard
> library? I don't see anyone having to link with -libc. So the tools
> are doing it automagically.

No, they aren't.  See djgpp.djl.

> Doesn't look so impossible now, does it?

Yep, it does.

> >In any case, forcing the programmer to change compilation switches to
> >debug is a Bad Idea (tm): one more general-purpose register makes a
> >world of difference on x86, so you are essentially debugging a
> >different program.
> 
> This is already done when one uses -fomit-frame-pointer simply to get
> a more extensive traceback. People do it all the time

What ``people''?  _I_ don't, and neither does anyone who works with
me.  You can debug a program even if it was compiled with
"-fomit-frame-pointer".

I _never_ debug or test a program compiled with switches different
from the switches used for the production build.

> >There are other DPMI hosts that support this feature.
> 
> Such as?

386Max and OS/2 Warp, to give just two examples.