Date: Thu, 2 Mar 2000 15:58:38 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender: eliz AT is
To: Kalum Somaratna aka Grendel <kalum AT crosswinds DOT net>
cc: djgpp AT delorie DOT com
Subject: Re: Fastest bitblt?
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On Thu, 2 Mar 2000, Kalum Somaratna aka Grendel wrote:

> > This would actually be a very bad idea: __djgpp_nearptr_enable invokes
> > a costly DPMI call.  Calling it too frequently will completely destroy
> > any hope for faster performance, which was the reason to use it in the
> > first place.
> 
> I think you may have misunderstood me here Eli.
> 
> I was suggesting the above technique (enable nearptrs before the code that
> requires it and disabling it afterwards) during the coding and beta
> testing versions, which woould keep the memory protection intact in the
> other (most) parts of the application. 

This is generally unwise: you are debugging a different program than the 
one you (and others) will use in production.  It's true that removing a 
system call is usually a small change, but even that change can be enough 
for some bug to raise its ugly head.