From:	"John M. Aldrich" <fighteer AT cs DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: unsigned char *far : problems
Date:	Wed, 04 Dec 1996 01:10:55 -0800
Organization:	Three pounds of chaos and a pinch of salt
Lines:	33
Message-ID:	<32A5401F.3FA2@cs.com>
References:	<01bbe146$95359e20$582449c2 AT default>
Reply-To:	fighteer AT cs DOT com
NNTP-Posting-Host:	ppp101.cs.com
Mime-Version:	1.0
To:	Thomas Harte <T DOT Harte AT btinternet DOT com>
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Thomas Harte wrote:
> 
> I have just moved over from a 'friendly' Microsoft compiler, and have tried
> compiling some old problems, but it (v2.01) won't compile with the
> following lines:-
> 
> unsigned char far *videobuf = (char far *)0xA0000000L;
> unsigned int far *videobufw = (int far *)0xA0000000L;

You are experiencing one of the fundamental problems that many people
have when switching from a real mode compiler to a protected-mode
compiler; things just don't work the same way.  In DJGPP, there _are_ no
segments; thus you don't need far pointers or MK_FP or any of the other
nasty Borland-isms you are used to.  However, because memory is
"protected", you can't just directly access the video RAM either.

Please download and read the DJGPP Frequently Asked Questions list
(v2/faq202b.zip) from the same place you got DJGPP.  Chapters 10, 17,
and 18 specifically deal with the issue of converting real mode graphics
programs into protected mode.  It's a lot more complicated than just
finding a substitute for 'far'.

-- 
John M. Aldrich <fighteer AT cs DOT com>                      

* Anything that happens, happens.
* Anything that, in happening, causes something else to happen,
  causes something else to happen.
* Anything that, in happening, causes itself to happen again, happens
  again.
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