Xref: news2.mv.net comp.os.msdos.djgpp:3309
From: Charles Sandmann <sandmann AT clio DOT rice DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Yet about MK_FP, pokeb, and peekb
Date: Tue, 30 Apr 1996 09:51:26 CDT
Organization: Rice University, Houston, Texas
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Message-ID: <318628ee.sandmann@clio.rice.edu>
References: <Pine DOT A32 DOT 3 DOT 90 DOT 960429134020 DOT 72338B-100000 AT canudos DOT ufba DOT br>
Reply-To: sandmann AT clio DOT rice DOT edu
NNTP-Posting-Host: clio.rice.edu
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

> 	Guys, sorry if I seem to insist at the same point (about 
> MK_FP). What I'd like to have is the facility of refering to a memory 
> position using a pointer, instead of a function (like dosmemput/get). On 
> the Borland version of a program of mine I had:
> 	char far *screen = MK_FP(0xb800,0);

1) write a function MK_FP
2) have it include sys/nearptr.h
3) enable near pointers
4) Compute the "near" address from __djgpp_conventional_base + arg1*16 + arg2
5) return this value

This might actually be a somewhat useful porting function to others.  I
have one someplace that was written just for the above porting reasons,
but I can't access it for several weeks.

> 	but I got a SIGSEGV singal at the execution of the mprotect 
> function. Sorry about my ignorance but why didn't it work ?!

Don't mess with mprotect.  It's there really only for making regions of
memory read only or no-access.