From: Andrea Martino <amartino AT iiic DOT ethz DOT ch>
Newsgroups: comp.os.msdos.djgpp
Subject: DJGPP & PMODE FEATURES
Date: Fri, 16 May 1997 09:32:15 +0200
Organization: Swiss Federal Institute of Technology (ETHZ)
Message-ID: <337C0D7F.4FAA@iiic.ethz.ch>
NNTP-Posting-Host: slab136.ethz.ch
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Lines: 18
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Precedence: bulk

Hy, I`m new to DJGP world...   :)

I want to acces video memory (0xA0000), but, when I try to do it, the
compiler returns a SIGSEG. I have to tell the compiler that I CAN
"touch" and "write" the video memory, but I don`t know how to do this.
What is the best way to do this?

Some people (<- thanx) told me that I MUST use some DPMI features like
selector & descriptors (GDT, LDT).

*** What are exactly selectors and descriptors (GDT & LDT)???
*** How knows the compiler that I CAN "write" some memory (like the
memory that I alloc), but I CAN`T "write" other memory (like video one)?

Thanx

P.S. It`s possible to carbon copy the answer to my e-mail adress
(because I cannot read the news everyday).