Message-ID:	<31FC9C96.71C4@pobox.oleane.com>
Date:	Mon, 29 Jul 1996 13:12:22 +0200
From:	Francois Charton <deef AT pobox DOT oleane DOT com>
Organization:	CCMSA
MIME-Version:	1.0
To:	djgpp AT delorie DOT com
Subject:	Re: DJGPP v2
References:	<Pine DOT LNX DOT 3 DOT 91 DOT 960729023100 DOT 17208I-100000 AT blackwidow DOT saultc DOT on DOT ca>

Mike A. Harris wrote:
> 
> On Fri, 26 Jul 1996, iNFiK wrote:
> 
> > How compatible is djgpp program sources to borland c++ source?
> > i mean, what version is djgpp equivilant to borland's c++?
> > how much are they different?
> > I just spent the last 3 hours DLing djgpp cause i heard it was good and
> > have a VERY old version of borland c++ (version 3.1).
> 
> It depends on how many Borland extensions your code uses.  So far,
> I've found tremendous compatibility.  I've recompiled various programs
> that are BC3.1 heavy, and only needed to change a couple of function
> calls.  The conio routines seem to be exact dupes of BC's, but I'm sure
> someone else can be much more specific.

I have been going from BC3.1 to djgpp 1.1 a year ago.

The main difference s that BC3.1 compiles 16-bit real mode, while djgpp does 
32-bit protected mode. 

When I tried to recompile programs, problems I got were : 
- ints are 16 bits on BC, 32 on DJGPP : use short and long instead
- interrupt code (with _interrupt), or _asm instructions, never work... don't 
try even to figure out how to port them... redevelop them rather...
-> however, low level IO, such as SVGA register adressing... usually works 
fine on both
- memory management is different : no more _far or _short pointers. However, 
 BC programs, with short pointers, and MK_FP instructions often compile fine. 
(watch out though, if you access video memory directly : the segment 
changes...).

regards 
F. Charton

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