From:	"Peter Remmers" <Peter DOT Remmers AT t-online DOT de>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: C Library: mmap() function
Date:	Mon, 2 Oct 2000 09:23:15 +0200
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Hans-Bernhard Broeker <broeker AT physik DOT rwth-aachen DOT de> schrieb ...
> Edmund Horner <ejrh AT paradise DOT net DOT nz> wrote:
> > Can the mmap() function be implemented in the DJGPP libc?
>
> mmap(), originally, is not a libc feature, but provided by the system.
> DPMI doesn't provide this feature, AFAIK, so we'ld have to simulate
> it.  The problem with such a simulation is that it would lose all the
> positive effects of mmap(), compared to straight-forward file I/O,
> which originally made it a good idea on Unix.  We have no alternative
> to just doing the file I/O, in order to emulate mmap(), killing any
> advantage it may have.

Wouldn't it be possible to write a filesystem extension for
say "/dev/fb0" which sits on VBE2.0, and then have a mmap() for getting
a pointer to the framebuffer?

I don't know exactly how this could be done. I think you would
HAVE to use the nearpointer hack for this.

BTA, a "normal" VESA library with its own API would do the same, right?

Anyway, just a thought...

Peter

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